Chemistry

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その溶液の凝固点は -4.658°C であった。 以下の問いに答えよ 1）塩酸の重量モル濃度を、HClと水の質量より求めよ。（○. O ○ Omolkg,単位はつけない） 2）凝固点降下より、重量モル濃度を求めよ。（○. ○○ Omolkg, 単位は つけない) 3）1）と2）が異なるのは、HCIが溶液中で解離しているからである。解離度をのとおくと、塩酸が全く解離してないときと比べてHClとイオンを合計した物質量は何倍になるか選択肢から選へ。 a) 1 b) 1- a c) 1+α d) 1+2α 4) 塩酸の解離度を求めよ。
Ions - Problems Give the ion symbol for the ion that has 27 protons and 24 electrons.
1. Explain how each treatment affected the rate of reaction. Describe the effect at a molecular level. a. Temperature: b. Surface Area: c. Concentration:
Multiple Choice Question Antidiuretic hormone (ADH) and oxytocin (OT) are synthesized in the Nerve impulses cause their release from the (where they are stored) into the bloodstream. posterior pituitary; hypothalamus hypothalamus; posterior pituitary hypothalamus; anterior pituitary anterior pituitary, posterior pituitary
Aluminum has an electron configuration of 1s^2 2s^2 2p^6 3s^2 3p^1. Carbon has an electron configuration of 1s^2 2s^2. How is the electron configuration of Aluminum different from Carbon? Select the two correct answers. (1 point) Carbon has 2 electrons in its p orbital. Carbon has 3 electrons in its p orbital. Aluminum has 4 electrons in its porbital. Carbon has 6 electrons in its p orbital. Aluminum has 6 electrons in its porbital.
Which of the following correctly describes the elements in the same group of the periodic table? The number of electrons in their valence shell does not change as one moves down the group. The atomic radius of these elements does not change as one moves down the group. The atomic radius of these elements decreases as one moves down the group. The number of electrons in their valence shell increases as one moves down the group.
Decide which element probably has a density most and least similar to the density of lithium.
A cation has a(n) charge. a. neutral b. positive c. alternating d. negative
If you are working as a forensic scientist and are given an unknown powder from a crime scene, what would you hope to find out about the powder?
What molecular force can allow molecules without dipoles to condense to form liquids and solids? London Dispersion Forces Metallic electron sharing Ionic Attraction Covatent Bonds In which of the following cities would you be able to cook a potato the fastest? New York City. NY (10 ft above sea level) Death Valley, CA (282 ft below sea leve) Madison WI ( 900 ft above sea level) Bouldet. CO (5430 ft above sea leve)) Classify the crystalline solid formed by Potassium Cyanide tonle Molecular Aloy Atomic
Fill in the missing information: symbol atom or ion? check all that apply number of protons number of electrons ----------------------------------------------------------------------------------- neutral atom cation anion 48 neutral atom cation anion 17 18 Mn^3+ neutral atom cation anion
Which is a pure substance? coffee silver chocolate air
Which of the following is an incorrect statement about running low-hydrogen electrodes? A. You should not use electrodes with missing fux. B. You should maintain a short arc. C. You should always whip the electrode. D. You should take only a few electrodes from the oven at a time.
A robot spacecraft returned samples from the planetesimal 98765 ALEKS, located in the outer Solar System. Mass-spectroso data on the isotopes of molybdenum in these samples: isotope mass (amu) relative abundance --------- ^100 Mo 99.9 52% ^97 Mo 96.9 48% Use these measurements to complete the entry for molybdenum in the Periodic Table that would be used on 98765 ALEKS. Use the correct number of significant digits.
Acetylene gas C2H2 undergoes combustion to form carbon dioxide and water when it is used in the oxyacetylene torch for welding. Balance the reaction and answer the following questions. C2H2(g) + O2(g) -> CO2(g) + H2O(g) (a) How many grams of water can form if 113 g of acetylene is burned? (b) How many grams of acetylene react if 1.10 mol of CO2 are produced?
You can see one sample of each of the elements we need to correctly assign to the periodic table in front of you. Based on their phase of matter and what you already learned, which of the elements is clearly not a metal? a) Sodium b) Neon c) Copper d) Calcium VIEW THEORY
Fill in the missing information: symbol atom or ion? check all that apply number of protons number of electrons Al^2+ neutral atom cation anion neutral atom cation anion 33 33 neutral atom cation anion 53 54
How many electrons are in a neutral ^41Ca atom? A 2 B 20 C 21 D 41
What does the solvent do in a solution? A. It forms a solid. B. It dissolves something else. C. It breaks into ions. D. It gets dissolved.
A medium that inhibits the growth of organisms other than the one being sought is termed a(n) Multiple Choice 59 synthetic medium. specific culture medium. selective medium. enrichment medium.
what is this molecule?
3 cm 5 cm 2 cm 6 cm 8 cm
Which term describes weathering? breaks down rock causes heating and cooling makes pebbles and rocks larger carries away fragments
Pot Luck You are preparing your special chicken stew for a pot-luck after the basketball tournament. You are running late and are trying to work quickly. Oh no-you forgot that youstill need to make a sandwich! You give the cutting board a quick wipe. There is still a little chicken on it, so you give it a rinse. There, that's better. You use the cutting board to cut bread, and prepare the sandwich in record time. The chicken stew must be ready by now. You dip your spoon into the stew for a taste. Yum! In goes the spoon again. Yup, it's done. You turn the stove off and decide to leave the pot to cool before putting it in the fridge (it should be cool enough by the time you get home later this evening). While quickly wiping the counter, you notice the extra chicken you thawed still sitting on the counter. You didn't need it after all. That's OK. You'll just put it back in the freezer for the next time. 1. What are the food safety errors committed? Several food safety errors were committed during making dinner for this potluck. First when 2. What is the correct/sanitary decision that should have been made?
5. Calculate the volume of an acetone sample with a mass of 7.89 g. Show your work. 0.79 g / mL x 7.89 6. A group of glass beads with a mass of 29.36 g is placed into a graduated cylinder containing 10.0 mL water. The water level rises to 21.7 mL. Calculate the density of the beads. Show your work.
How many protons do all isotopes of Cu have? 40 4 29 20
Taux d'avancement Effectuer un calcul Une solution aqueuse d'acide lactique C3H6O3, l'un des acides présents dans le lait, de volume V=100 mL et de concentration c=0,10 mol · L^-1 a un pH égal à 2,1. La base conjuguée est l'ion lactate C3H5O2. a. Écrire l'équation de la transformation. b. Calculer la quantité de matière n0 d'acide lactique introduit et les valeurs des avancements, maximal xmax, et xf à l'état final d'équilibre. c. Calculer le taux d'avancement final τf. d. Calculer la constante d'équilibre K de la réaction.
Which statement best describes the structure that results from the following curved arrows: [ [θ° oH^⊕ ↔ ? ] The resulting structure is a valid resonance structure. The resulting structure is NOT a valid resonance structure, because the octet rule has been violated. The resulting structure is NOT a valid resonance structure, because a single bond has been broken.
In an experiment, a 0.3208 g sample of biphenyl (C12H10) is burned completely in a bomb calorimeter. The calorimeter is surrounded by 1.191 x 10^3 g of water. During the combustion the temperature increases from 27.33 to 29.65°C. The heat capacity of water is 4.184 J · g^-1 · °C^-1. The heat capacity of the calorimeter was determined in a previous experiment to be 795.1 J · °C^-1. Assuming that no energy is lost to the surroundings, calculate the molar heat of combustion of biphenyl based on these data. C12H10(s)+(29 / 2) O2(g) -> 5 H2O(l)+12 CO2(g)+ Energy Molar Heat of Combustion = kJ / mol
What do the blue-colored blocks indicate?
osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the gas constant R. Suppose the osmotic pressure of a certain solution is measured to be 23 atm at an absolute temperature of 338 K. Write an equation that will let you calculate the molarity c of this solution. Your equation should contain only symbols. Be sure you define each symbol other than R.
Write the symbol of a period 3 element that forms a +3 cation. Write the symbol of an ion from group 17 (7A) with 36 electrons.
An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11 . How many protons does boron have? 0 6 16 5 11
The compound magnesium chloride is a strong electrolyte. Write the reaction when solid magnesium chloride is put into water. Include states of matter in your answer. MgCl2(s) → Mg^2+(aq) + 2Cl^-(aq)
What is the molarity of a solution prepared by dissolving 4 grams of NaOH in 100 mL of water? 5.00 M 0.50 M 1.00 M 0.01 M
Separation based on particle size Electrolysis Distillation Chromatography Filtration Evaporation
The effects of competitive inhibitors can be diluted out by substrate but those of uncompetitive and mixed inhibitors cannot.
[Na2O2 + HOH -> NaOH + O2
What do heartburn (high stomach acid), cavities, bee stings have in common?
Which scientist presented arguments to support a theory of geological change, proposing that the earth was subject to slow but continuous erosion and uplift?
liters
How many covalent bonds are formed in SO4?
A chemistry student needs 35.0 g of diethylamine for an experiment. By consulting the CRC Handbook of Chemistry and Physics, the student discovers that the density of diethylamine is 0.706 g · cm^-3. Calculate the volume of diethylamine the student should pour out. Be sure your answer has the correct number of significant digits.
What invention, at the end of the medieval period, made books less expensive, helping to spread literacy and independent thought to more Europeans?
The expression [ left(frac2 a^-65 b^-1 / 2right)^-1 ] equals (n a^r / b^t) where n , the coefficient, is: (r), the exponent of (a), is: (t), the exponent of (b), is:
A proton donor is an acid base colloid salt mixture
NaCN, DMSO, O*C
In chemical reactions, heat is converted into chemical energy (the potential energy stored in chemical bonds) or vice versa. Bond energy is the energy required to takes energy to break a bond, bond energies are always positive. Conversely, energy is released when bonds are formed. Thus, the enthalpy change for a reaction can be approximated from ΔHran=Σ(ΔH breaking )+Σ(ΔH forming ) where H represents bond energies for the breaking (positive bond energy) or forming (negative bond energy) of a bond and Hmas represents the overall enthalpy for the reaction. Use the table to answer questions about bond energies. Bond Bond energy (kJ / mol) C-C 347 C=C 611 C-H 414 C-O 360 C=OinCO 799 O-O 142 O=O 498 H-O 464 Calculate the approximate enthalpy change, ΔHmax, for the combustion of one mole of methane as shown in the balanced chemical equation: CH4+2 O2 → 2 H2O+CO2 Use the values you calculated in Parts A, B, C, and D, keeping in mind the stoichiometric coefficients Express your answer to three significant figures and include the appropriate units.
How many moles of C6H12O6 are contained in each volume of aqueous C6H12O6 solution? Be sure each of your answer entries has the correct number of significant figures. Part 1 of 2 8.3 L of a 0.52 M solution Part 2 of 2 520 mL of a 0.48 M solution
The most common minerals in the upper part of the continental crust are colored silicates. They are felsic in composition, and their color is a direct result of their elemental composition.
Classify these amino acids as acidic, basic, neutral polar, or neutral nonpolar. Place each item into the appropriate bin. Tryptophan Tyrosine Glutamic Acid Valine Threonine
Which type of unconformity is usually easiest to spot, since layers are on top of nonlayered crystalline rock?
Given the table of standard molar entropy values of heat substance in the reaction below, what is the standard change in entropy for the reaction? 4NH3(g) + 3O2(g) → 2N2(g) + 6H2O(g)
Which term refers to the contribution of protein to the osmotic pressure of the blood?
Which compounds would you expect to contain one or more covalent bonds? Compounds - CBr4 - S8 - H2O - S2F10 - N2O3
In addition to the anti-VEGF antibody, a VEGFR primary antibody was also added. At which position do you expect the band for VEGFR to appear? Remember that in SDS-PAGE, proteins are separated according to their molecular weight. a) VEGFR runs at a lower molecular weight than VEGF b) VEGF and VEGFR run at the same molecular weight c) VEGFR runs at a higher molecular weight than VEGF d) VEGFR cannot be detected by Western blotting
A high fever causes an enzyme to lose its three-dimensional structure and function. Which bonds are broken when a protein denatures? hydrogen bonds non-polar covalent bonds ionic bonds polar covalent bonds
Drag and drop the chemical formula to classify each as a compound or an element.
What is the oxidation level in the molecule below? Type in the number: 1,2,3, etc.
The following cation has a total of how many resonance structures?
Question 2 (6 points) What is the pH of a solution if there are 0.00258 grams of H+ present in 1 L of this solution? Round your answer to one decimal place. Question 3 (6 points) You have two solutions, A and B, separated by a semipermeable membrane. Solution A is 0.5 moles of KCl in 1 LH2O and Solution B is 0.8 moles of dextrose in 1 LH2O. Which side has the higher osmotic pressure at 25°C and what is that pressure? Enter the letter solution with the higher pressure as the Unit. Question 4 (6 points) Over the course of 12 minutes a reaction uses up 120 grams of the reactant Hif. What is the rate of
What information is necessary to review in order to be considered familiar with the Safety Data Sheet (SDS) of a substance? Select one or more: Literature examples of use of the substance Handling, storage, and reactivity information Hazard warnings Personal protection and first aid recommendations Identification and description of substance
In each of the following examples, identify the type of colloid: Part A the meringue topping on a pie
Review I Constan Part A What is the molecular geometry of a molecule with 4 outer atoms and 1 lone pair on the central atom? Enter the molecular geometry of the molecule. View Available Hint(s) Submit Part B What is the molecular geometry of a molecule with 4 outer atoms and 2 lone pairs on the central atom? Enter the molecular geometry of the molecule. View Available Hint(s) Submit Part C What is the molecular geometry of a molecule with 2 outer atoms and 3 lone pairs on the central atom? Enter the molecular geometry of the molecule. View Available Hint(s)
Part C Ionic compounds are formed from ionic bonds, whereby an electron is transferred from the metal cation to the nonmetal anion. Ions form solid lattices of ions. Covalent compounds form solids through the attraction of two covalent molecules. Since the attraction between two covalent molecules is weak compared to the ionic bonds holding an ionic compound together, ionic compounds tend to have higher melting points. Which of the following compounds has the highest boiling point? Br2 NaBr HBr BrF
A histogram has the same shape and horizontal scale as a histogram but the vertical scale is marked with relative frequencies instead of actual frequencies.
After tissue repair is completed, factor XII catalyzes the formation of a plasma enzyme called kallikrein, that, in turn, converts an inactive plasminogen into , a fibrin-dissolving enzyme that breaks up the clot. Multiple Choice prothrombin plasminogen ences plasmin fibrin thromboplastin
Virtual Lab 0 - ALEKS Tutorial ALEKS - Leah Pons - Knowledge - www-awu.aleks.com/alekscgi/x/lsl.exe/1ou-IgNsIkr7j8P3jH Initial Knowledge Check Question 1 Count the significant digits in each of these measurements: measurement number of significant digits ------ 5.5 × 10^-1 mL 17700 kg 0.006700 J -6.0 × 10^-3 kJ / mol IDon't Know Submit Feels colder Now Search
The organ system that contains glands that secrete hormones to regulate growth, reproduction, and metabolism is the system.
Find the (a) mean, (b) median, (c) mode, and (d) midrange for the data and then (e) answer the given questions Listed below are the highest amounts of net worth (in millions of dollars) of all celebrities. What do the results tell us about the population of all celebrities? Based on the nature of the amounts, what can be inferred about their precision? 235, 190, 175, 155, 150, 150, 135, 135, 135, 135 results. However, the result from part (c) shows that the most common celebrity net worth is equal to the mode Based on the nature of the amounts, what can be inferred about their precision? A. The values all end in 0 or 5, so they appear to be rounded estimates B. Since celebrity information is public, these values can be assumed to be unrounded C. The values are all whole numbers, so they appear to be accurate to the nearest whole number. D. Since no information is given, nothing can be said about the precision of the given values
Homework Question 8, 3.2.25-T Part 5 of 6 HW Score: 95.51%, 12.42 of 13 points Points: 0.67 of 1 Save The accompanying data represent the weights (in grams) of a random sample of 48 MM plain candies. Complete parts (a) through (f). Click the icon to view the weights of the MM plain candies. (a) Determine the sample standard deviation weight. 0.036 gram(s) (Round to three decimal places as needed.) (b) On the basis of the accompanying histogram, comment on the appropriateness of using the Empirical Rule to make any general statements about the weights of MMs. A. The histogram is approximately bell-shaped so the Empirical Rule can be used. B. The histogram is not approximately bell-shaped so the Empirical Rule cannot be used. C. The histogram is not approximately bell-shaped so the Empirical Rule can be used. D. The histogram is approximately bell-shaped so the Empirical Rule cannot be used. (c) Use the Empirical Rule to determine the percentage of MMs with weights between 0.803 and 0.947 gram. Hint: x̄=0.875. 95% (Type an integer or decimal. Do not round.) (d) Determine the actual percentage of MMs that weigh between 0.803 and 0.947 gram, inclusive. 95.8% (Round to one decimal place as needed.) (e) Use the Empirical Rule to determine the percentage of MMs with weights more than 0.911 gram. % (Type an integer or decimal. Do not round.) MM Candy Weights 0.87 0.90 0.91 0.86 0.90 0.93 0.87 0.88 0.91 0.88 0.88 0.87 0.86 0.84 0.82 0.84 0.89 0.88 0.88 0.86 0.87 0.90 0.81 0.83 0.83 0.94 0.92 0.89 0.93 0.86 0.84 0.86 0.91 0.91 0.82 0.84 0.89 0.93 0.84 0.84 0.88 0.95 0.86 0.85 0.79 0.91 0.88 0.87
Sulfur has an atomic number of 16. How many covalent bonds can sulfur form? 4 2 0 1
Hydrogen sulfide decomposes according to the following reaction, for which Kc=9.30 x 10^-8 at 700°C: 2 H2S(g) ⇌ 2 H2(g) + S2(g) If 0.59 mol of H2S is placed in a 3.0-L container, what is the equilibrium concentration of H2(g) at 700°C?
Determine the rate of reaction for the following chemical reaction, based on the information given: 2 H2O2(aq) → 2 H2O(l) + O2(g) Reaction started with 1.4 M H2O2 and ended with 0.6 M after 0.8 minutes. Make your answer's precision to two decimal places. Include the correct units in your answer for full credit.
What enzyme converts angiotensin I to angiotensin II? Use the acronym only and all 3 letters must be capitalized!
Compared to the rusting of iron, silver tarnish is most notable for which of the following reasons? Silver tarnishes to form a metal sulfide instead of a metal oxide.
According to Arrhenius, an acid and a base will react to give a salt plus water.
Class of Carbohydrate 1. 2. 3. 4. 5.
The volume of a single strontium atom is 4.15 × 10^-23 cm^3. What is the volume of a strontium atom in microliters? □ μL
Which SCBA component attaches to the SCBA facepiece and directly controls airflow to the wearer? (210) Heads up display Air cylinder Regulator PASS device
Chapter 2 Quiz Question 2 of 8 (1 point) Question Attempt: 1 of 1 Draw the bond-line (skeletal) formula of a compound with the molecular formula C5H10Br2 that meets the specified condition. Part 1 of 2 All of the carbon atoms belong to methylene (-CH2-) groups.
How many unpaired electrons are there in the following ground-state atoms and ions? If none, enter a zero in the answer box. O has unpaired electrons P3- has unpaired electrons
Copper(II) sulfate forms several hydrates with the general formula CuSO4 · x H2O, where x is an integer. If the hydrate is heated, the water can be driven off, leaving pure CuSO4, behind. Suppose a sample of a certain hydrate is heated until all the water is removed, and it's found that the mass of the sample decreases by 18%. Which hydrate is it? That is, what is x?
Select the new equilibrium constant, K, of a reaction multiplied by a factor n, that is n(a A+b B ↔ c C+d D). K=n K K=K/n K=K^n
The element bromine is in group and period The element hydrogen is in group and period The element cobalt is in group and period
This question has multiple parts. Work all the parts to get the most points. Figure out what is wrong with the following molecular formula and write the correct formula: (Enter the elements in the order they appear in the wrong formula.) a N 2 H 4 (hydrazine) Correct formula: (b) C 4 H 10 (butane) Correct formula:
What will be formed when CH2CH2 reacts with bromine in the dark?
Convert the following measurement. 0.0074 g/L = □ mg/dL
Draw the expanded, or complete, structural formula for the hydrocarbon represented by the line-angle, or skeletal, structure shown. Draw the complete structural formula. Include all hydrogen atoms.
What is the mechanism for the reaction of chloromethane, CH3Cl, with hydroxide in the equation below? CH3Cl + OH^- -> CH3OH + Cl^- A. electrophilic addition B. electrophilic substitution C. nucleophilic substitution D. nucleophilic addition
If a nutrient or dietary supplement plays a role in maintaining a body part, such as bone, or promoting a body process, such as digestion, the food can be labeled with a(n) claim.
All of the following are required to be included on the Nutrition Facts panel EXCEPT: Polyunsaturated fat Trans fat Cholesterol Dietary fiber
Stoichiometry Calculating and using the molar mass of diatomic elements A chemist determines by measurements that 0.0850 moles of nitrogen gas participate in a chemical reaction. Calculate the mass of nitrogen gas that participates. Be sure your answer has the correct number of significant digits. g × 10
The shortest wavelength within the visible spectrum is light. A) violet B) orange C) blue D) red
It is often necessary to do calculations using scientific notation when working chemistry problems. For practice, perform each of the following calculations. (5.30 × 10^-5)(9.46 × 10^5)=□ (3.47 × 10^4) / (9.60 × 10^4)=□ ((5.30 × 10^-5)(9.60 × 10^4)) / ((1.00 × 10^-8)(3.47 × 10^4))=□
Buffers are solutions that keep the pH neutral. make the pH more basic. keep pH relatively stable. make the pH more acidic.
Atoms, Ions and Molecules Deducing the ions in a binary ionic compound from its empirical formula 3 / 5 Complete the table below by writing the symbols for the cation and anion that make up each ionic compound. The first row has been completed for you. ionic compound cation anion --------- NaCl Na+ Cl- AuF3 AuBr MnO2 CrI3
Atoms, Ions and Molecules Deducing the ions in a binary ionic compound from its empirical formula 0/5 Complete the table below by writing the symbols for the cation and anion that make up each ionic compound. The first row has been completed for you. ionic compound cation anion ------------------------------- NaCl Na+ Cl- CrCl3 CrS2 CuF ZnBr2
Which of the following factors would speed up the rate of a chemical reaction? Larger reacting particles Lower temperature Removing the biological catalysts High concentration of reacting particles
Determine the products for the following reactions.
Are all drugs capable of causing side effects?
Atoms, Ions and Molecules In the table below, there are descriptions of an experiment on samples of three different chemical compounds. Decide whether the compound is ionic or molecular, if you can. If there is not enough information to decide, choose can't decide in the third column. compound description ionic or molecular? --------- 1 Compound 1 is a clear liquid with a strong smell. If heated gently it boils at 115 °C. Onic 2 Compound 2 is a dull white smooth solid which does not conduct electricity. Applying an ordinary laboratory burner to the material only makes the substance hot, it does not otherwise change. In fact, the substance can't be melted or even softened by any ordinary laboratory equipment. (can't decide) 3 Compound 3 is a hard white smooth odorless solid, which is insoluble in water. If the flame from an ordinary laboratory burner is held on the solid for 10 minutes, the solid grows hot to the touch but does not soften. O molecular
Encuentra la media, mediana, moda, rango y desviación media 5,10,6,7,10,8,9
Consider a hypothetical chemical reaction: A+B → C+D (In this equation A, B, C, and D stand for some unknown chemical formulas.) Here is an energy diagram for the reaction: Use the energy diagram to answer these questions. What is the heat of reaction? [1] kJ / mol Is the reaction exothermic or endothermic? Exothermic Endothermic Neither Can you determine the activation energy? Yes, it's [square] kJ / mol No. Can you determine the activation energy of the reverse reaction? C+D → A+B Yes, it's [square] kJ / mol No.
Factor the trinomial completely. 25x^2(y-3)^2+35x(y-3)^2+49(y-3)^2 Select the correct choice below and fill in any answer boxes within your choice. A. 25x^2(y-3)^2+35x(y-3)^2+49(y-3)^2= B. The polynomial is prime.
A CaSOA system is at equilibrium at 25°C. CaSO4(s) ⇌ Ca^2+(aq) + SO4^2-(aq) Which direction will the reaction shift if the equilibrium system is warmed to 40°C ? Ksp = [Ca^2+][SO4^2-]
Which of the following is NOT a way to satisfy the octet rule? a having a full outer electron shell b transferring inner electrons to fill the outer electron shell c transferring valence electrons in an ionic bond d sharing valence electrons in a covalent bond
The chemical formula for dimethyl ether is: CH3OCH3 Calculate the molar mass of dimethyl ether. Round your answer to 2 decimal places. g · mol^-1 × 10
During a strenuous workout, an athlete generates 1940 kJ of heat energy. What mass of water would have to evaporate from the athlete's skin to dissipate 1940 kJ of heat?
Gold and other precious metals are easy to store for long periods of time because they will not spoil, making them an example of which of the following? Double coincidence of wants Unit of account Store of value Medium of exchange
We still have no proof that life can exist on other planets. Kepler-160e is the best candidate for an Earth-like planet. Most exoplanets have been found orbiting red dwarf stars. A planet's surface must have liquid water for life to exist.
Consider a sodium (Na) atom. a. What is the mass of one atom of Na (include units) b. Given that 1 amu=1.6606 × 10^-24 grams, find the mass of a mole of Na atoms. c. What are the units of your calculation?
A hydrogen atom absorbs a photon, and an electron transitions from energy level 1 to 3. For scientific notation answers, please enter 1.23 e 21 to represent 1.23 x 10^21 What is the electron's initial energy? What is the electron's final energy? Ephoton = J h = s fphoton = s cphoton = m / s lambdaphoton = m
Balance each equation. (Use the lowest possible whole number coefficients. Omit states-of-matter from your answers.) (a) Mg(OH)2 + HCl -> MgCl2 + H2O + -> + (b) Ca(NO3)2 + H2S -> CaS + HNO3 + -> + (c) CH4 + O2 -> CO2 + H2O + -> + (d) CaCO3 + HCl -> CaCl2 + CO2 + H2O + -> + +
Provide the correct IUPAC name for Pb(SO3)2.
Convert from moles to grams. 1) 2.3 mol Mn 2) 0.017 mol C 3) 6.2 mol H2 4) 30 mol H2O 5) 5.78 mol NaCl 6) 0.5610 mol SiO2 7) 0.478 mol N2O4 8) 1.8 * 10^-3 mol H2CO3 9) 0.0054 mol Mg(NO3)2
Stoichiometry Writing a chemical equation from a molecular movie The movie below shows some molecules in a tiny sample of a mixture of gases. Drag the slider to see how the molecules move. Does a chemical reaction happen during this movie? O yes O no If a chemical reaction does happen, write a balanced chemical equation for it.
Just How Faithful Is Old Faithful? The name 'Old Faithful' is synonymous with the geologic features known as geysers. But whot, exactly, is a geyser, and how does it work? How Geysers Start Our Earth consists of many regions where magma, or hot lava. lies beneath the surface. This magma works like a burner on a stove, hooting any water in the ground until it grows very hot Mast water beneath Earth's surface comes from rain and melting snow. This water passes through cracks in the earth and collects underground. If this water lies close enough to hot magma, it heats and begins to boll: Why does the author include a section on Yellowstone's Old Faithful? to introduce the idea that even the most reliable of geysers can be inconsistent to illustrate the importance of geysers to our natural world and our environment's health to provide information about geysers and how we can preserve them worldwide to explain how geysers are formed below Farth : surface and how they erupt
Complete the table to determine the nuclear symbol for this neutral atom. Nuclear Symbol Subatomic Particles Protons: 72 To which element does this atom belong?
1. For which type of measurement would you use the following measuring devices? a. Thermometer b. Digital electronic balance c. Pipette d. Graduated cylinder e. Ruler 2. For the abbreviated units listed below, give the full unit name, the type of measurement they are used for (Example: mass, volume, length, temperature). Unit Full Name of the Unit Type of Measurement --- --- --- mL Milliliter Volume m μm ng g L °C °F
On the first chemistry test, 15 students got As, 20 students got Bs, and 19 students got Cs. Part A What is the percent of students who received Bs? Express your answer to the ones place. Express your answer to two significant figures and include the appropriate units. Part B What is the percent of students who received Cs? Express your answer to the ones place. Express your answer to two significant figures and include the appropriate units. The percent of students who received Cs=
Part IV. Essay. 10 Points. Please answer the following as complete as possible. 20. Entropy is a fantastically important concept in thermodynamics and thus it is the focus of one of the laws of thermodynamics (the 2nd one). Tell me why understanding entropy is important in life and death, and chemistry. Use specific examples, equations, and relationships to other chemical concepts. Extra credit (+1): If the ΔG for the reaction C(s, diamond) → C(s, graphite) is -3 kJ, how come are diamonds not spontaneously turning into graphite?
Quarter 2 Assessment: Part 1 Water Quality Research and Guiding Questions Below are several questions that you may use to guide your research regarding the water quality at OMHS and around the world. Please be sure to answer all questions in as much detail as you can. Also be sure to record where you found the information (a website link will suffice). Read the following articles and answer the questions: Health Effects of Lead in Drinking Water cwswater Lead in drinking water infographic 1. Who is at the greatest risk for lead poisoning? (paragraph 1) 2. According to the EPA, drinking water makes up what percent of a person's exposure to lead? (paragraph 2) 3. What are two steps you can take to reduce your exposure to lead in drinking water? (paragraph 3) Drinking Water I WHO 4. Aporoximately what percent of the world's
Assuming all outer atoms are the same element, which molecule is polar?
If grams of a substance are given, will you use Avogadro's as your first step?
7. What functional group is not present in the following molecule? A) amine B) ketone C) alkene D) amide
Application Practice Problems: Limiting Reactant Stoichiometry Instructions: Complete the following conversions, showing all of the steps in your work. Copper (I) sulfide is produced from the synthesis of copper and sulfur 2 Cu + S → CuS 2. What is the limiting reactant when 80.0 g Cu reacts with 25.0 g S 80.0 Cu × 1 mol Cu / 63.55 g = 1.25 mol × 1 mol S / 2 mol Cu = 0.830 mol S 25.0 g S × 1 mol S / 32.07 g = 0.779 mol × 2 mol Cu / 1 mol S = 1.558 mol Cu Cu is limiting b. What is the maximum number of grams of Cu2S that can be formed when starting with the quantities of each reactant given above? c. How many grams of the excess reactant will remain after the limiting reactant is consumed?
Clothing and Fibers Blends Cotton Fire Retardant Knitted Linen Man Made Natural Nylon Permanent Pres: Polyester Rayon Silk Stamped Water Repelle Wool Woven Use the clues to fill in the puzzle with the correct word. There are NO SPACES between words in an answer. Across 2. A natural fiber that is versatile, comfortable and inexpensive. 5. A natural fiber that comes from a worm; it is comfortable and resists wrinkling. 8. This is when the yarn is woven at right angles to form a fabric. 9. A synthetic fiber that is elastic and wrinkle resistant, but pills easily. 10. This fabric finish will not wrinkle. 11. This is when the fabric has the pattern applied after it has been woven. 13. A natural fiber that is warm, and keeps it's shape well, but moths love to eat it! 14. This is another name for a synthetic fiber. 16. This is what you call a fiber that is made of more than one type of fiber. 17. This is what you call fibers that we get from nature. 18. This fabric finish causes a fabric to resist water. Down 1. A Synthetic fiber that is wrinkle resistant, but doesn't breathe. 3. This fabric finish will extinguish itself if it catches on fire. 4. A synthetic fiber that resembles silk, but easily gets static electricity. 6. This is when the yarns are interlaced or looped to form a fabric. 7. A synthetic fiber that resembles wool and is warm, but pills easily. 12. A synthetic fiber that resembles cotton, linen and silk. 15. A natural fiber that is comfortable, and absorbent, but wrinkles easily.
Will these ions make compounds? Li^1+ ? Ca^2+ and F^1- ? O^2- ? O^2- and Cl^1- ?
4. Which scale is used to measure recipe ingredients from 1 / 4 ounce to 1 pound to 2 pounds? a. Baker's scale b. Digital scale c. Portion scale d. Balance scale 5. A very shallow pan about 1 inch deep used for anything from baking cookies to roasting vegetable is called a a. sheet pan. b. cake pan. c. crêpe pan. d. springform pan Which type of knife is used to slice bread and cake? a. Utility b. Tourné c. Santoku d. Serrated An oyster knife is used to a. trim oysters. b. shuck oysters. c. chop oysters and clams. d. crack oysters, clams, and other shellfish.
9.16 × 10^24 molecules of CO2
How much energy is evolved or absorbed as heat if 8.50 kg of Ca(OH)2 reacts with a stoichiometric amount of CO2? Heat = k
You want to determine the % of an acetic acid sample solution by acid/base titration. Therefore, you prepare a NaOH solution. To determine the exact concentration of this NaOH you titrate exactly 390.3 mg KHPhthalate ( M=204.22 g / mol ) with this NaOH solution requiring 8.2 ml. Subsequently you use this NaOH solution to titrate 25.0 ml of your acetic acid sample ( M(acetic acid)=60.05 g / mol, density of solution =1 g / ml ) resulting in a consumption of 6.9 ml of the NaOH solution. Please give all relevant reaction equations (with correct stoichiometry). Calculate the exact concentration (in mol / L) of the NaOH solution. Please calculate the weight-% of acetic acid in the sample solution. Which indicator would you use for this titration/at which pH range would you expect the equivalence point?
Which element did Mendeleev predict would have an atomic mass of 68 and be a soft metal? a gallium b erbium c potassium d magnesium
Atoms, Ions and Molecules Identifying common polyatomic ions Complete the following table: Some polyatomic ions name chemical formula chlorate anion hydronium cation CN^- nitrate anion
3) Graph of y=B(t) a) What is the domain of B(t)? Write it in reduced interval notation. b) What is the range of B(t)? Write it in reduced interval notation. c) Evaluate B(2). d) Pretend that ε>0 is a very small positive number. You don't know its specific value. It is just really small. Explain why this statement is false: When t ∈(2-ε, 2+ε), then B(t) is close to -6.
Draw the Lewis structure of NO2-.
A recent study of patients found that of 95 alcoholic patients, 82 had elevated cholesterol levels, and of 305 nonalcoholic patients, 64 had elevated cholesterol levels. If a patient is selected at random, find the probability that the patient is the following. Round your answers to three decimal places. Part 1 of 3 P( alcoholic with elevated cholesterol) = Part 2 of 3 P( nonalcoholic) =
When the following molecule is hydrogenated using H2 gas and a Pt / Pd catalyst, what will the product be?
Prepare general journal entries to record these transactions using the following titles: Cash (101); Accounts Receivable (106); Office Supplies (108); Office Equipment (163); Automobiles (164); Building (170); Land (172); Accounts Payable (201); Notes Payable (250); Common Stock (307); Dividends (319); Consulting Revenue (403); Salaries Expense (601); and Utilities Expense (602). The company purchased land valued at 45,000 and a building valued at 160,000. The purchase is paid with 30,000 cash and a note payable for 175,000. Note: Enter debits before credits.
A molecule of the compound responsible for the odor of garlic
8 In which process are microbes genetically changed to produce animal proteins? A. adaptation B. variation C. genetic engineering D. selective breeding
What are the configurations for the two chirality centers? A. a=R, b=R B. a=S, b=S C. a=R, b=S D. a=S, b=R
At a drug rehab center 32% experience depression and 30% experience weight gain. 13% experience both. If a patient from the center is randomly selected, find the probability that the patient (Round all answers to four decimal places where possible.) Tip a. experiences neither depression nor weight gain. b. experiences depression, given that the patient experiences weight gain. c. experiences weight gain, given that the patient experiences depression. d. Are depression and weight gain mutually exclusive? O no O yes e. Are depression and weight gain independent? O yes O no Calculator Scratchwork Area
acid strong or weak? species present at 10^-6 mol/L or greater when dissolved in water --- H2CO3 weak H2S weak HClO2 weak HI strong
dissolved in a liter of water. acid strong or weak? species present at (10^-6 mol/L) or greater when dissolved in water --- --- --- (mathrmH2 mathrmCO3) weak (mathrmH2 mathrm~S) weak (mathrmHClO2) weak HI strong
Given lim as x approaches 11 of f(x)=-5 and lim as x approaches 11 of g(x)=-12, evaluate lim as x approaches 11 of [5f(x)-2g(x)]. lim as u approaches +1 of [5f(x)-2g(x)]=-1 lim as u approaches ++ of [5f(x)-2g(x)]=-49 lim as v approaches . of [5f(x)-2g(x)]=1 lim as x approaches +... of [5f(x)-2g(x)]=49
Question 2 Under which of the following conditions would one mole of Ne have the highest entropy, S? 137°C and 25 L 27°C and 25 L 137°C and 35 L 27°C and 35 L
Multiple Select Question Select all that apply Calcium absorption in the small intestine is achieved with the help of calcitonin. hydroxyapetite. calcium-binding protein. Vitamin D.
Which genetic method attempts to predict how an individual will react towards drugs? Pharmacogenomics Crispr GWAS Gene therapy
drop the chemical formula to classify each as a compound or an element. Compound Element Chemical Formula H-O-H, O=C=O drop the correct answers into the boxes. You can also click the correct answer, then the box where it should go. Reset my answers.
Select the correct VSEPR shape for the molecular compound. CF4 □ PCl3 □ CH2S □ CO2 □ SeF2 □
50.09 × 100/1014 =
Decide which element probably forms a compound with oxygen that has a chemical formula most and least similar to the chemical formula of the compound formed by oxygen and strontium.
6. Which of the following is an example of a destructive force? - A) Glacier formation - B) Sediment deposition - C) River erosion - D) Mountain building
Write the expanded structural formula of 2-pentanol.
With the exception of water, matter when heated a Solidifies b. Contracts c. Expands d Condense
The diagonals of this rhombus are 7 kilometers and 30 kilometers. What is the area of the rhombus?
Calculate the amount of heat needed to melt 182 g of solid ethanol (CH3CH2OH) and bring it to a temperature of -16.0°C. Round your answer to 3 significant digits. Also, be sure your answer contains a unit symbol.
Question 4 What stretching frequencies (in cm^-1) are present in the structure below? 1745 1800 1715
Which of the following carbonyls have a stretching frequency around 1745 cm^-1? Caution: More than one answer is possible. none of these
27. Which of the following should you use to extinguish a small fire in a beaker or flask? a) Water b) Fire extinguisher (Class A) c) A fire blanket or a lid d) None of the above 28. What should you do if you experience a chemical splash in your eye? a) Rinse with water immediately for at least 15 minutes and seek medical help b) Wait to see if the pain subsides c) Rub your eyes to alleviate the irritation d) Use an eye drop solution and continue working 29. Where is the emergency eyewash station located in most labs? a) Near the main entrance b) Next to the chemical storage area c) Near the sink or in a designated area d) In the storage closet with safety equipment 30. What should you do if you catch fire while in the laboratory? a) Run to the exit immediately b) Drop to the floor and roll to smother the flames c) Use a fire extinguisher to put out the flames d) Wait for the instructor to take care of the situation
Balance the entire chemical reaction using an atom inventory. Remember to balance each element in the reaction. Al + Cl2 -> AlCl3 When the equation is balanced, what is the coefficient for chlorine, Cl2?
How many barium atoms are in the compound below? Ba(MnO4)2
A student needs to determine the density of an irregularly shaped object. This student prepares a solution mixture where the object is suspended. The collected data is shown in the table below. Liquid Density (g/mL) Volume (mL) Glycerol 1.2610 4.57 Isopropanol 0.797 3.27 Determine the density of the object. Round your answer to 3 significant digits.
H3PO4 Express your answers using four significant figures. Enter your answers numerically separated by commas. mass % of H, P, O = %
Covalent bonds form salts, whereas ionic bonds form molecules. True False
A selenium ion ( Se^2- ) is in its ground state. How many electrons are in a neutral selenium atom? How many electrons are in a selenium ion ( Se^2- )? Complete the ground-state electron configuration of a selenium ion ( Se^2- ) using noble gas notation.
A chemistry student needs 25.0 g of ethanolamine for an experiment. By consulting the CRC Handbook of Chemistry and Physics, the student discovers that the density of ethanolamine is 1.02 g/cm^(-3). Calculate the volume of ethanolamine the student should pour out.
Match the pH value on the left with the correct description on the right. (i) Instructions pH 7 pH 3 pH 11 basic (alkaline) neutral
A chemistry student must write down in her lab notebook the concentration of a solution of sodium thiosulfate. The concentration of a solution equals the mass of what's dissolved divided by the total volume of the solution. Here's how the student prepared the solution: - The label on the graduated cylinder says: empty weight: 9.050 g - She put some solid sodium thiosulfate into the graduated cylinder and weighed it. With the sodium thiosulfate added, the cylinder weighed 76.3 g . - She added water to the graduated cylinder and dissolved the sodium thiosulfate completely. Then she read the total volume of the solution from the markings on the graduated cylinder. The total volume of the solution was 124.99 mL . What concentration should the student write down in her lab notebook? Be sure your answer has the correct number of significant digits. g · mL^-1 × 10
A chemist needs to know the mass of a sample of aniline to 4 significant digits. He puts the sample on a digital scale. This is what the scale shows: If this measurement is precise enough for the chemist, round it to 4 significant digits. Otherwise, press the "No solution" button.
Experiments were done on a certain pure substance X to determine some of its properties. There's a description of each experiment in the table below. In each case, decide whether the property measured was a chemical or physical property of X, if you can. If you don't have enough information to decide, choose can't decide in the third column. property experiment physical or chemical? --------- 0 A sample of solid X is carefully weighed and put inside a vented flask. The flask is heated until oxygen gas starts being produced. After no more oxygen gas is produced, the contents of the flask are removed and weighed, and from the decrease in weight the value of O may be calculated. - O physical - O chemical - O (can't decide) R Into one chamber of an electrochemical cell, a solution of X is introduced, along with a metal electrode. In the other chamber a solution of a known oxidizing reagent O is introduced, along with another metal electrode The voltage across the electrodes is proportional to the tendency of O to react with X. By measuring this voltage, the value of R may be calculated. - O physical - O chemical - O (can't decide) E A thin sample of X is put between metal plates. A radio-frequency electric current is applied to the plates and passes through the sample. From the measured voltage across the plates the value of E may be calculated. - O physical - O chemical - O (can't decide)
Thé diagram shows three lines with some marked angle measures. Find the missing angle measures marked with question marks.
Al2O3(s) -> 2 Al(s) + 3/2 O2(g) ΔH° = 1675 kJ / molrxn Calculate the energy required to decompose 400 g of Al2O3. Answer in kJ.
Part B A covalent compound is composed of a nitrogen atom, a hydrogen atom, and a carbon atom. How many electrons should the Lewis structure of the covalent compound contain? Express your answer numerically as an integer. View Available Hint(s)
Chemical Reactions Identifying the correct sketch of a compound in aqueous solution Imagine a small amount of each compound in the table below is dissolved in water. Pick the sketch that best shows what the solution would look like, at the atomic level. The large number of faint red and white molecules in the background of each sketch represent the water solvent. Also, the colors of the solute atoms may not mean the same element in each sketch. For example, solute oxygen atoms could be colored yellow in the first sketch but blue in the second. Chlorine atoms could be colored blue in the first sketch but yellow in the second. And so on. Note for advanced students: the sizes of the atoms and any bond angles may not be accurate. compound pick a sketch OCl₃ (Drag the slider to choose an image) NH₃ (Drag the slider to choose an image)
1.5.2 Test (CST): Humans and the Environment Question 17 of 25 Which of these methods of commercial fishing is linked to excessive bycatch? A. Trolling B. Handline fishing C. Seining D. Long-line fishing SUBMIT
Identify the base SI unit for temperature. Kelvin Celsius Fahrenheit Centigrade
Carbon