Chemistry Homework Questions & Answers Archive

Calculate the number of grams of the product Fe2O3 that form. Be sure your answer has the correct number of significant figures. g Fe2O3 × 10

Collectively, hydrochloric acid, water, pepsin, and mucus all are components of what fluid? saliva gastric juice pancreatic juice

Place the following elements in order of decreasing atomic size: tellurium, bromine, argon, cesium, strontium, and selenium. Rank from largest to smallest. To rank items as equivalent, overlap them.

Which element is most abundant in the Earth's crust? a. Oxygen b. Silicon c. Calcium d. Magnesium Compounds are made up of more than one element. Which of the following represents a compound? a. N2 b. NH3 c. H2 d. All of the above

Which of the following is a highly compact structure that is very commonly used to transition from one region of secondary structure to another in a globular protein?

As a general rule, compounds have strong intermolecular forces, and their boiling and melting points tend to be higher than compounds of similar molecular mass. (A) Nonpolar, nonpolar (B) Polar, nonpolar (C) Polar, polar (D) Nonpolar, polar

What is the result of the oxidation of butanal?

Identify the MO diagram for N2. diagram A N2 valence e^-: 6 diagram B Identify the MO diagram for O2. diagram B O2 valence e^-: diagram A Identify the MO diagram for F2. diagram A F2 valence e^-: diagram B

Specify the formal charge at each of the labeled atoms, a - c, in each of the following structures.

Complete the table below by filling in the principal quantum number n and angular momentum quantum number I for each electron subshell listed. subshell principal quantum number n angular momentum quantum number I --- --- --- 6 f 6 d 3 s 4 d

What is the likely cause for the difference in evaporation points of the compounds A and D? The molecules have different numbers of oxygen atoms. The molecules have different amounts of dispersion forces. The atoms have different types of bonds holding the molecule together. The molecules have different intermolecular forces

A solution contains one or more of the following ions: Ag+, Ca2+, and Co2+. Lithium bromide is added to the solution and no precipitate forms. An excess of lithium sulfate is then added to the solution and a precipitate forms. The precipitate is filtered off and lithium phosphate is added to the remaining solution, producing a precipitate. Which ions are present in the original solution? Co2+ Ag+ Ca2+. Write a net ionic equation for the formation of the precipitate observed after the addition of lithium sulfate. Include physical states. net ionic equation: Write a net ionic equation for the formation of the precipitate observed after the addition of lithium phosphate. Include physical states.

What is the molecular weight of a gas if a 21.0 g sample has a pressure of 836 mm Hg at 25.0°C in a 2.00 L flask? ( R=0.0821 L atm / mol K) 11.1 amu 243 amu 1.89 amu 234 amu none of the above

A check mark is placed in the square column in the accounts payable subsidiary ledger to indicate that the transaction was posted to the creditor's account in the accounts payable subsidiary ledger.

Two main thyroid hormones regulate metabolism: triiodothyronine (T3), and tetraiodothyronine (T4), also called

Draw the Lewis structure of IF5 and then determine its electron domain and molecular geometries. A tetrahedral / t-shaped B octahedral / t-shaped C linear / see-saw D pentagonal / bent (109.5) E octahedral / square pyramidal

MISSED THIS? Watch KCV: The Titration of a Weak Acid and a Strong Base, IWE: Weak Acid-Strong Base Titration pH Curve; Read Section 18.4. You can click on the Review link to access the section in your eText. Consider the titration of a 24.0-mL sample of 0.110 M HC2H3O3(Ka=1.8 x 10^-5) with 0.120 M NaOH. Part A Determine the initial pH. Express your answer to two decimal places. pH=

In the context of small molecules with similar molar masses, arrange the intermolecular forces by strength. Strongest Weakest Answer Bank hydrogen bonding London dispersion forces dipole-dipole interactions

Which of these ionic salts would you expect to have the highest melting point based on Coulombic interactions? Ca3 P2 Mgg P2 Be3 P2 Srg P2

Which of the following will alter analyte retention times when its chemical nature is changed? (Note: There may be more than one correct response) The LC Stationary phase The LC mobile phase

Identify the molecular formula of the alkyne: A hydrocarbon with 10 carbons that is an alkyne.

Which type of polymerization process could be used with these monomers and what type of bonds will form in the polymer? Addition polymerization, amide bonds Condensation polymerization, ester bonds Condensation polymerization, amide bonds Addition polymerization, ester bonds

8 of 14 Which is a device used to measure the heat absorbed or released during a chemical or physical process? calorimeter. heat capacity. heatameter. joule.

Cadmium, a heavy metal, is toxic to animals. Mushrooms, however, are able to absorb and accumulate cadmium at high concentrations. Some governments have a safety limit for cadmium in dry vegetables at 0.48 part per million (ppm). A research team measured the cadmium levels in a random sample of edible mushrooms, where the hypothesis test is to decide whether the mean cadmium level in the sample is less than the governments' safety limit. The null and alternative hypotheses are H0: μ=0.48 ppm, Ha: μ<0.48 ppm. Complete parts (a) through (e) below. A. type II error B. correct decision because a false null hypothesis is rejected C. correct decision because a true null hypothesis is not rejected D. type I error e. Now suppose that the results of carrying out the hypothesis test lead to nonrejection of the null hypothesis. Classify that conclusion by error type or as a correct decision if in fact the mean cadmium level in that type of mushrooms is below the safety limit of 0.48 ppm . Choose the correct answer below. A. correct decision because a false null hypothesis is rejected B. type II error C. correct decision because a true null hypothesis is not rejected D. type I error

Arrange these elements according to atomic radius. Largest radius Smallest radius Answer Bank Rb K Na Li Cs

Solve the following logarithmic equation. Be sure to reject any value logarithmic expression. Give the exact answer. log6 x=2 Rewrite the given equation without logarithms. Do not solve for x x=6^2

The molecular geometry of ClO4- is The molecular geometry of BrO2- is The molecular geometry of NO2- is The molecular geometry of SO4^2- is

Use the table of annual expenses to calculate the category expense contribution for rent. Payroll: 403,120 Advertising: 8,532 Raw Materials: 214,570 Rent: 51,440 Insurance: 8,111 Utilities: 12,804 Services: 6,880 [?] % Round to the nearest whole percent.

Describe how you can transform a nonstandard normal distribution to the standard normal distribution. To transform a nonstandard normal distribution to the standard normal distribution you must transform each data value x into a z-score. Which of the following formulas is used to convert an x value into a z-score? A. z=(x-μ)²/σ B. z=x-μ C. z=(x-μ)/σ D. z=(μ-x)/σ²

Order these chemical species by increasing pH of an 0.1 M aqueous solution of each. That is, imagine making an 0.1 M solution of each species. Select 1 next to the species that makes the solution with the lowest pH. Select 2 next to the species that makes the solution with the next higher pH, and so on. Notice that some of the rankings have been filled in for you already: Also notice that water is on the list. For that particular case, just compare the pH of pure water to the pH of the other solutions. Note for advanced students: for all charged species, you may assume the necessary counterions act as neither acids nor bases. species relative pH of 0.1 M aqueous solution ------ H2S 4 C6H5NH3+ (Choose one) HCOO- (Choose one) HS- (Choose one) HCOOH- H3O+ (Choose one) C6H5NH2 H2O 7

Test Yourself: Find the pH if we add another 1.00 g of tris hydrochloride. [B]=12.43 g / L / 121.14 g / mol = 0.1026 M [BH+]=4.67 g / L / 157.59 g / mol = 0.0296 M Henderson-Hasselbalch Equation The Henderson-Hasselbalch equation is a rearranged form of the Ka equilibrium expression. Ka=[H+][A-]/[HA] Henderson-Hasselbalch equation for an acid: HA ↔ H+ + A- pH = pKa + log ([A-]/[HA]) Henderson-Hasselbalch equation for a base: Ka=Kw / Kb BH+ ↔ B + H+ pH = pKa + log ([B]/[BH+]) Note: If activities are included, pH = pKa + log ([A-] γA-]/[HA] γHA) pKa applies to this acid

Part C 0.20 M KI Express your answer to two decimal places.

Use the sample data and confidence level given below to complete parts (a) through (d). In a study of cell phone use and brain hemispheric dominance, an Internet survey was e-mailed to 2514 subjects randomly selected from an online group involved with ears. 1023 surveys were returned. Construct a 95% confidence interval for the proportion of returned surveys. a) Find the best point estimate of the population proportion p. (Round to three decimal places as needed.) b) Identify the value of the margin of error E. E= (Round to three decimal places as needed.) c) Construct the confidence interval. <p< (Round to three decimal places as needed.)

Based on molecular structure, arrange the following binary compounds in order of decreasing acid strength. Rank compounds from strongest to weakest. To rank items as equivalent, overlap them. NaH H2S H2Te HI

In the reaction 2 H2O -> 2 H2 + O2, 2.0 mol water will produce how many grams of O2? 16 32 36 64 Which of the following reactions is correctly balanced? N2 + H -> 2 NH3 2 H2O + C -> CO + 2 H2

Increasing the temperature of 50 grams of water by 1°C requires how many calories?

Question 46 ( 0.5 points) One of the functional groups from vinyl acetate was lost in order to make the links between the vinyl acetate molecules resulting in the polymer polyvinyl acetate. Name the lost functional group. Your options are: alcohol, aldehyde, alkene, alkyne, amine, amide, aromatic, cyclo-, ester, ether, halo-, imine, ketone, and thiol.

What type(s) of intermolecular forces are present in each of the following molecules? Check all that apply for each part. Part 1 of 3 H2 - London dispersion - Dipole-dipole - Hydrogen bonding - Start over - None of the above

Chapter 7 - Part 2 - Homework Question 3 of 11 (9 points) Question Attempt: 1 of Unlimited What type(s) of intermolecular forces are present in each of the following molecules? Check all that apply for each part. Part 1 of 3 London dispersion Dipole-dipole Hydrogen bonding None of the above Part 2 of 3 H2O London dispersion Dipole-dipole Hydrogen bonding None of the above

Balance the chemical equation below using the smallest possible whole number stoichiometric CH3(CH2)5CH3(l) + O2(g) → CO2(g) + H2O(g)

What is the IUPAC name of the following compound?

Calculate the volume (in mL) of 0.100 M CaCl2 needed to produce 2.00 g of CaCO3(s). There is an excess of Na2CO3. Molar mass of calcium carbonate = 100.09 g / mol

A superhero is rendered powerless when exposed to 45 or more grams of a certain element. A 450 year old rock that originally contained 400 grams of this element was recently stolen from a rock museum by the superhero's nemesis. The half-life of the element is known to be 150 years. a) How many grams of the element are still contained in the stolen rock? b) For how many years can this rock be used by the superhero's nemesis to render the superhero powerless? a) The stolen rock still contains about grams of the element. (Do not round until the final answer. Then round to two decimal places as needed.)

How often must disinfection solutions be made and disposed of?

The body system responsible for regulating nutrient levels is the Muscular system Endocrine system Cardiovascular system Skeletal system

Calculate the grams of solute needed to prepare each of the following. Part B 4.30 L of a 0.200 M CaCl2 solution Express your answer with the appropriate units.

State your conclusion to the hypothesis test. If a 95% confidence interval for μ is calculated to be (21.4,27.9), what would be the result of a H0: μ=27 vs H1: μ ≠ 27 The null hypothesis would not be rejected

Question 5 1 / 1 pts 5. What is the product of elimination reaction shown in the box? A) C) B) D)

Suppose a chemical reaction generated a 50% nitrogen / 50% oxygen (by volume) mixture of gas that had a total volume of 22.4 liters at STP. This gas sample is composed of: - 28 mole of nitrogen and 32 mole of oxygen. - 1 mole of nitrogen and 1 mole of oxygen. - 50 mole of nitrogen and 50 mole of oxygen. - 0.5 mole of nitrogen and 0.5 mole of oxygen. - none of the above

Construct the expression for Kb for the weak base, N2H4. N2H4(aq) + H2O(l) ⇌ OH^-(aq) + N2H5+(aq) Based on the definition of Kb, drag the tiles into the numerator or denominator to construct the expression for the given base. Kb=

QUESTION 34 OF 50 Staff should check refrigerators or coolers where food is stored regularly for the appropriate temperature. Which of the following temperature readings ensures that food will not spoil? Choose only ONE best answer. A The temperature should not exceed 20 degrees Fahrenheit. B The temperature should not exceed 40 degrees Fahrenheit. C The temperature should not exceed 60 degrees Fahrenheit. CONFIRM

Write a balanced half-reaction for the reduction of bismuth oxide ion (BiO3-) to bismuth ion (Bi3+) in basic aqueous solution. Be sure to add physical state symbols where appropriate.

Question 7 2 pts Which is an example of a physical change? the melting of snow the digestion of food the rusting of an iron nail the cooking of an egg the burning of butane in a lighter

Question 3 (1 point) Saved What is the index of hydrogen deficiency of a dicyclohexane molecule? 0 4 2 1 3

Current Attempt in Progress Combined oral contraceptives decrease the likelihood of pregnancy by suppressing FSH and LH. preventing development of a dominant follicle in the ovary. blocking implantation in the uterus. inhibiting transport of ova and sperm in the uterine tubes. all of these choices. eTextbook and Media Save for Later

학생 4 명의 음악 수행 평가 점수에 대한 편차를 조사하여 나타낸 표이다. 옳지 않은 것은? 편차(점) 5 -3 x -2 (1) A 의 점수가 가장 높다. (2) B 는 평균보다 낮은 점수를 받았다. (3) A 는 D 보다 점수가 7점 높다. (4) C 는 평균 점수를 받았다. (5) 점수가 낮은 학생부터 차례대로 나열하면 B, C, D, A 이다.

3x = -(π/2)x - 4n - 37^7(x + n)

Question 10 2 pts According to LeChatelier's principal, what happens to the equilibrium of a reaction when you increase the concentration of the products? The equilibrium shifts towards the reactants nothing happens The equation shifts towards the products

A 5.27 g sample of an unknown salt (MM=116.82 g / mol) is dissolved in 150.00 g water in a coffee cup calorimeter. Before placing the sample in the water, the temperature of the salt and water is 23.72°C. After the salt has completely dissolved, the temperature of the solution is 28.54°C. What quantity in moles of the unknown salt were used in the reaction?

Review the experiment carried out by Bozkur's team using Nicotiana benthamiana and Phythophthora infestans. For the experiment, match the following: Normal CHUP1 gene infection with Phythophtora infestans A. standardized treatment Status of CHUP1 gene B. independent variable Chloroplasts movement to infection site C. control treatment Shutting off photosynthetic machinery in chloroplasts D. dependent variable

Classify the characteristics as qualities of either acids or bases. Acid Base Answer Bank bitter flavor dissolves some metals turns litmus paper red sour flavor turns litmus paper blue feels slippery

185,000 gallons × 3.78541 liters ≡ 700,289.85 liters Rounding the result to 4 digits this would be 700.3 liters

fif dL= 4 L square ks = 7000 s 6000 mm= ） 4 Mg= square g

Imagine a compound with the formula X3. Each of the X has 6 valence electrons, What will be the electron pair geometry and the molecular geometry? eg. tetrahedral ; tetrahedral e.g trigonal planar ;m.g bent e.g. trigonal planar ;mg. trigonal planar e.g. trigonal planar ;mg. trigonal pyramidal

Which of the following elements would have a very different electron affinity value compared to the others? A Ne B Al C O D F E Na

C4H8O is an example of an organic compound because it is made of non-metals which could only make covalent bonds. True False Inorganic compounds are chemical substances that are made mostly of carbon and hydrogen. True False Aside from carbon and hydrogen, what other elements are usually found in organic compounds? Halogens

An unknown compound has the following chemical formula: Fe(NO3)x where x stands for a whole number. Measurements also show that a certain sample of the unknown compound contains 9.40 mol of nitrogen and 3.1 mol of iron. Write the complete chemical formula for the unknown compound.

What is the total number of electrons needed in order to build the Lewis structure for N2O?

Plavix is used to treat acute coronary syndrome. Patients with a recent history of myocardial infarction or stroke are also treated with Plavix. Identify the functional groups in Plavix.

States of Matter Calculating mole fraction in a gas mixture A 10.00 L tank at 22.2 °C is filled with 19.0 g of sulfur hexafluoride gas and 8.88 g of boron trifluoride gas. You can assume both gases behave as ideal gases under these conditions. Calculate the mole fraction of each gas. Be sure each of your answer entries has the correct number of significant digits. gas mole fraction sulfur hexafluoride [] boron trifluoride []

What is the depth at which carbonate begins to dissolve called? How about the depth were all carbonate dissolves completely?

Which is the major organic product formed by this reaction? Studying the summary chart in Lesson VI.3.5 will help to correctly determining the products. A) C) B) D) E) No net reaction or none of these is a major product

A chemist prepares a solution of iron(II) chloride (FeCl2) by measuring out 1.50 g of FeCl2 into a 300 mL volumetric flask and filling to the mark with distilled water. Calculate the molarity of Cl- anions in the chemist's solution. Be sure your answer is rounded to 3 significant digits. mol/L × 10^5

The chemical formulae of some acids are listed in the first column of the table below, and in the second column it says whether each acid is strong or weak. Complete the table. List the chemical formula of each species present at concentrations greater than about 10^(-6) mol / L when about a tenth of a mole of the acid is dissolved in a liter of water. acid strong or weak? species present at 10^(-6) mol/L or greater when dissolved in water HBrO3 strong HBr strong H3PO4 weak HNO2 weak

Radioactive fallout from testing atomic bombs drifted across a region. There were 210 people in the region at the time and 39 of them eventually died of cancer. Cancer experts estimate that one would expect only about 33 cancer deaths in a group this size. Assume the sample is a typical group of people. a) Is the death rate observed in the group unusually high? b) Does this prove that exposure to radiation increases the risk of cancer? State the null and alternative hypotheses. Choose the correct answer below. A. H0: p=0.1571 HA: p<0.1571 B. H0: p=0.1571 HA: p>0.1571 C. H0: p=0.1571 HA: P ≠ 0.1571 D. The assumptions and conditions are not met, so the test cannot proceed.

What is the systematic name for the given compound? 2-bromopropane What is the common name for the given compound? isobron

3,5-diethyl-1-heptane

Calculate the standard entropy change for the reaction at (25^circ mathrmC). Standard molar entropy values can be found in this table. [ mathrmMg(mathrmOH)2(mathrm~s)+2 mathrmHCl(mathrm~g) longrightarrow mathrmMgCl2(mathrm~s)+2 mathrmH2 mathrmO(mathrm~g) Delta Smathrmixn=square ] (square) J/K TOOLS [ x 10^y ]

Question 1 of 41 Which of the following are chemical properties of matter? A mass B volume C density D flammability

Write a complete chemical formula, including physical state symbol, for each element listed below in its standard state. The first row of the table has been completed for you. element formula ------ iron Fe(s) nitrogen potassium thorium

What concentration of ethanol is considered optimum for disinfectant? Why not 100%?

During the dressing processes all the following occur except: (Exam 1 L2Ch 2) a) converting black ore into red ore b) removing some impurities by magnetic separation c) removing oxygen from the red ore d) converting the ore into suitable size

A M^2+ ion has five electrons in the 3d subshell and is derived from a metal in the first transition metal series. Based on the description provided, enter a chemical symbol for what element M might be.

Provide the IUPAC name for the following compound:

A compound contains 62.1% C, 10.4% H and 27.5% O. What is the empirical formula of the compound? CH2O C2H4O C3H4O C3H6O

Reference the following balanced equation: 2 H2(g) O2(g) ... 2 H2O(g) If you have 30.0 g of hydrogen gas burned in excess oxygen gas, how many moles of water can you theoretically make? 60 moles water 7.5 moles water 15 moles water 30 moles water

What is the mass percent of Cl in ZnCl3?

Fill in the Blank Question The direct materials budget details the physical units and cost of planned direct material purchases. (Enter only one word per blank) Read About the Concept Need help? Review these concept resources. 18 of 60 Concepts completed

Which statement best describes the process of diffusion? The process by which a gas spreads through a space occupied by another gas

An atom or ion has 43 neutrons, 36 protons, and 36 electrons. Identify the element symbol, and determine the mass number and charge for this atom or ion. element symbol: mass number: charge:

State the total number of valence electrons in HNO2.

Which of the following reactions is an acid-base reaction? A AgNO3(aq) + KF(aq) -> AgF(s) + KNO3(aq) B NH3(aq) + HF(aq) -> NH4+(aq) + F^-(aq) C NO2(aq) + Al(s) -> NH3(g) + AlO2(aq) D CH4(g) + 2 O2(g) -> 2 H2O(g) + CO2(g)

Balance the following chemical equation (if necessary): Ca(OH)2(s) + H3PO4(aq) → H2O(l) + Ca3(PO4)2(aq)

Hydrogen peroxide can be prepared in several ways. One method is the reaction between hydrogen and oxygen, another method is the reaction between water and oxygen. Calculate the ΔGrxn of each reaction using values from the table of thermodynamic properties. (1) H2 (g) + O2(g) ⇌ H2O2 (l) ΔGrxn= □ kJ · mol^(-1) (2) H2O(l) + 1/2 O2(g) ⇌ H2O2(l) ΔGrxn^e= □ kJ · mol^(-1)

Answer the questions based on the structures below: a). b). What is the molecular formula of a? What is the molecular formula of b ? Are these the structural formulas, condensed formulas or line structures? (remember, you can't enter subscripts so just leave the answer as regular text)

Question 7 of 30 Which of the following is true concerning successive ionizations of an atom and its ions? A Each successive ionization requires less energy to achieve. B All ionizations require the same amount of energy. C The amount of energy required to achieve a successive ionization doubles with each electron removed. D Each successive ionization requires increasing amounts of energy.

States of Matter Predicting the relative boiling points of pure substances Rank the elements or compounds in the table below in decreasing order of their boiling points. That is, choose 1 next to the substance with the highest boiling point, choose 2 next to the substance with the next highest boiling point, and so on. substance chemical formula or Lewis structure boiling point A Co B H-C≡C-H C H2 D O=C=O

States of Matter Identifying the important intermolecular forces in pure compounds Decide which intermolecular forces act between the molecules of each compound in the table below. compound Intermolecular forces (check all that apply) --------------------------------------------------------- dispersion dipole hydrogen-bonding hydrogen sulfide ammonia carbon monoxide silicon tetrafluoride

Consider the balanced chemical reaction below. When the reaction was carried out, the calculated theoretical yield for carbon dioxide was 546 grams, but the measured yield was 483 grams. What is the percent yield? Fe2 O3 + 3 CO → 2 Fe + 3 CO2

Which correctly defines molar volume of an ideal gas? the volume that is occupied by 1 mol of an ideal gas at STP, which is 22.4 L the volume that is occupied by 1 mol of an ideal gas at STP, which is 1.0 L the volume that is occupied by 22.4 mol of an ideal gas at STP, which is 1.0 L the volume that is occupied by 22.4 mol of an ideal gas at STP, which is 22.4 L

Predict the type of bond (ionic, covalent, or polar covalent) one would expect to form between the following pairs of elements. a. Cs and Cl b. N and N c. C and F d. Rb and Br e. H and H f. Si and Cl

Question 1 The term "heavy metals:" - Is related to the chemical composition of all toxic metals - Accurately describes the high density of all toxic metals - All of these are true - Originated from the discovery of the toxicity of relatively dense mercury and lead

Question 12 (4 points) Nerve cell adhesion molecules (N-CAMs) A) are crucial in the production of neurotransmitters B) release nerve growth factor C) are crucial for the development of neural connections D) are found on "pathfinder" neurons

learning - Courses activity/6001003/assessment 6.1.3 Exam: Semester 1 Exam Question 14 of 25 Which of the following is an example of a chemical change? A. A liquid evaporating B. A solid dissolving C. A precipitate forming D. A mixture forming SNBMIT 'REVIOUS

Complete the table by inputting in the n value, l value, and number of orbitals for each given sublevel. sublevel n value l value number of orbitals ------------ 6 d 5 s 2 s

Which shows the following expression after the negative exponents have been eliminated? a^3 b^-2 / a b^-4, a ≠ 0, b ≠ 0 a^3 b^4 / a b^2 -a^3 b^4 / a b^2 a^3 b^-4 / a b^-2 a b^4 / a^3 b^2

Which of the following acids is the weakest? The acid is followed by its Ka value. HNO2, 4.6 × 10^-4 HF, Ka=3.5 × 10^-4 HCN, Ka=4.9 × 10^-9 CH3COOH, Ka=1.8 × 10^-6

A pharmacist adds 10 mL of a 20 %(w / v) solution of a drug to 500 mL of D5W for parenteral infusion. What is the percentage strength of the drug in the infusion solution? (a) 2 % v / v (b) 2 % w / v (c) 1.96 % w / v (d) 0.39 % w / v

A chemist titrates 180.0 mL of a 0.2084 M acetic acid (HCH3CO2) solution with 0.5401 M KOH solution at 25°C. Calculate the pH at equivalence. The pKa of acetic acid is 4.76. Round your answer to 2 decimal places.

A gas sample contains 4.0 g of CH4 and 2.0 g of He. What is the volume of the sample at STP?

What is the oxidation state of S in H2SO4? A. +6 B. +8 C. -2 D. -4

Apex Learning - Courses /public/activity/4000001/assessment Pretest: Unit 4 Question 9 of 30 How does a balanced chemical equation show the conservation of mass? A. It shows that the total number of moles of substances stays the same. B. It shows that the mass of the products is greater than the mass of the reactants when a reaction increases the moles of substances. C. It shows that the mass of the reactants is greater than the mass of the products when gases are produced by the reaction. D. It shows that the number of each type of atom stays the same. SUBMIT ५ PREVious

What is the percent of phosphorus by mass in phosphoric acid, H3PO4? Use 1.008 g / mol for the molar mass of hydrogen, 16.00 g / mol for the molar mass of oxygen, and 30.97 g / mol for the molar mass of phosphorus. Your answer should be rounded to three significant figures. Do not include units in your answer.

Fill in the systematic names of the following chemical compounds. Note: for compounds containing hydrogen, you may give the common name instead. molecular formula name of compound SiO- SiO2 SO2 SO3 NH3

A compound contains 76.6% C, 6.38% H and 17.0% O. Which of the following is the correct empirical formula for the compound? a C6H6O b CH2O c C2H2O d C4H4O e CHO

Sulfuric acid is normally purchased at a concentration of 18.0 M. What is the volume of the sulfuric acid solution is required to prepare 206.7 mL of 0.225 M aqueous H2SO4? (Remember to add acid to water rather than water to acid.)

Which of the following intermediates is thought to occur in the mechanism by which alkenes are hydrated in the presence of acid? carbanion carbocation free radical alkyne carbene

Lithium combines with oxygen to form lithium oxide. Write the balanced chemical equation for this reaction. What is the coefficient for lithium? 4 3 2 1 None of the above.

The diameter of an atom is approximately 1 x 10^-10 m. What is the diameter in centimeters? 1 x 10^-8 cm 1 x 10^-16 cm none of these 1 x 10^-13 cm 1 x 10^-7 cm

Unit 6 Homework Question 5 of 17 (1 point) I Question Attempt: 1 of 3 Assuming fixed amounts of gases, complete the following table by filling in any missing values corresponding to gases A, B, and C. Round each of your answers to 2 significant figures. Note: Reference the Conversion factors for non-SI units table for additional information. Gas P1 V1 T1 P2 V2 T2 --------------------- A 0.29 atm 4.34 L 340. K 0.84 atm 1.70 L 381. K B 1.1 atm 46.0 L 47. °C 574. mmHg 88. °C C 496. mmHg 329. mL 284. K 508. mmHg 0.81 L 450 K

Which of the following is considered a non-modifiable risk factor for Atherosclerosis? Select one A. Obesity B. Smoking C. Age D. Hyperlipidemia E. Hypertension

In which of these five solutions will a precipitate of Ag2CrO4(s) form? Ksp for Ag2CrO4(s)=9.0 x 10^-12. (Select all that apply.) a. 1.0 x 10^-7 M AgNO3 and 6.0 x 10^-4 M K2CrO4 b. 1.0 x 10^-6 M AgNO3 and 6.0 x 10^-4 M K2CrO4 c. 1.0 x 10^-5 M AgNO3 and 6.0 x 10^-4 M K2CrO4 d. 1.0 x 10^-3 M AgNO3 and 6.0 x 10^-4 MK2CrO4 e. 1.0 x 10^-2 M AgNO3 and 6.0 x 10^-4 M K2CrO4

1. Complete the following table: Compound MW equiv. mmol density mL ------------------------------------------------------------------- methyl benzoate 136.15 g / m 31 0.01674 0.930 sulfuric acid (18M) 0.4507 1.088 0.414 nitric acid 0.01674 0.310 (15.9M) 5.088 0.320 2. What is the theoretical yield for this reaction? 4. The textbook shows the nitration of benzene to occur with heating (50-55°C), why is an ice bath employed in the nitration of methyl benzoate?

(a) Dioxane has a boiling point of 101°C. Could you separate dioxane from methylcyclohexane by distillation? Explain why or why not, based on the liquid and vapor compositions during the distillation. (b) How might these liquids be separated?

A titration of 47.1 mL of a sulfuric acid (H₂SO₄) solution of unknown concentration with a standardized 1.55 M Ba(OH)₂ solution required 23.0 mL to reach the second equivalence point. What is the concentration of the H₂SO₄ solution?

The names and chemical formulae of some chemical compounds are written in the first two columns of the table below. Each compound is soluble in water. Imagine that a few tenths of a mole of each compound is dissolved in a liter of water. Then, write down in the third column of the table the chemical formula of the major chemical species that will be present in this solution. For example, you know water itself will be present, so you can begin each list with the chemical formula for water (H2O). Note: "major" chemical species are those present in concentrations greater than 10^-6 mol / L. compound formula major species present when dissolved in water --------- methanol CH3OH propylene glycol C3H6(OH)2 glycerol C3H8O3

Consider these compounds: A. PbI2 B. AgI C. CO(OH)2 D. CaCrO4 Complete the following statements by entering the letter corresponding to the correct compound. Without doing any calculations it is possible to determine that silver chromate is more soluble than , and silver chromate is less soluble than It is not possible to determine whether silver chromate is more or less soluble than by simply comparing Ksp values.

Why do DNA fragments in gel electrophoresis travel away from the negative electrode? Selected answer will be automatically saved.For keyboard navigation, press up/down arrow keys to select an answer. a ONA is positively charged, so it is attracted to the negative electrode b. DNA is negatively charged, soit is attracted to the positive electrode C The agarose gel in negatively charged d The agarose gel is positively charged

A chemist determined by measurements that 0.010 moles of potassium participated in a chemical reaction. Calculate the mass of potassium that participated in the chemical reaction. Be sure your answer has the correct number of significant digits.

Part A A mixture initially contains A, B, and C in the following concentrations: [A]=0.650 M, [B]=0.600 M, and [C]= 0.300 M. The following reaction occurs and equilibrium is established: A + 2 B ↔ C At equilibrium, [A]=0.490 M and [C]=0.460 M. Calculate the value of the equilibrium constant, Kc. Express your answer numerically.

What is the oxidation number of magnesium in MgI2?

Which substance is in excess when 1.50 mol of aluminum bromide is reacted with 2.50 mol of barium hydroxide in the following equation? A) BaBr2 B) Al(OH)3 C) Ba(OH)2 D) AlBr3

If 0.167 moles of NaCl are dissolved in a 250.0 mL solution, what is the concentration of the NaCl solution?

Given the following mixed-phase reaction at equilibrium: BaF2(s) + 2 H2O(l) ⇌ Ba(OH)2(s) + 2 HF(aq) with ΔrH>0 Indicate the direction will shift after each indicated perturbation. Addition of more solid BaF2: Addition of pure HF: Decrease the temperature of the reaction: Add pure water to dilute the reaction:

90. Which of the following compounds contains the Mn ion? a. MnS b. MnBr2 c. Mn2O3 d. MnO 91. What is the net charge of the ionic compound calcium fluoride? a. 2- b. 1- c. 0 d. 1+ 92. Which of the following units is NOT an official SI unit? a. kilogram b. ampere c. mole d. liter

Which of the following is an example of chemical energy being converted into another form? A. Paper being torn B. Heating cold water C. Burning a log in a fireplace D. A roller coaster going downhill

Question 7 (10 points) What is the IUPAC name of this molecule?

If a spoon of copper metal is placed in a solution of ferrous sulfate: a Copper will precipitate out b Iron will precipitate out c Copper and iron will precipitate d No reaction will take place

Imagine you have a gallon of the substance called 2-propanol. Under usual conditions, 2-propanol is a flammable co Part A Which of the following statements about the properties of 2-propanol is correct? The mass of the gallon of 2-propanol is an intensive property. The fact that 2-propanol is colorless is a chemical property. The temperature at which the 2-propanol freezes is an intensive property. The fact that 2-propanol is flammable is a physical property. Submit Request Answer Provide Feedback Search

Mercury is a shiny liquid. Calculate its density if 1417.5 g of the substance occupies 105 mL. Be sure your answer has the correct number of significant figures.

Measurement and Matter Multiplication and division of measurements Decide whether each proposed multiplication or division of measurements is possible. If it is possible, write the result in the last column of the table. proposed multiplication or division Is this possible? result (4.0 cm) · (8.0 cm) =? yes no (1.0 cm) · (9.0 s) =? yes no (1.0 g^3) · (0.029 kg) =? yes

Essentials of General, Organic, and Biochemistry Denise Guinn THIRD EDITION presented by Macmilan Learning The pH of blood is tightly regulated and normally falls between 7.35 and 7.45. A condition called acidosis occurs when blood pH falls below 7.35 and is too acidic. A condition called alkalosis occurs when blood pH rises above 7.45 and is too basic. A patient with respiratory depression is at risk of developing an acid-base imbalance in the blood. Why does this imbalance occur and what is the resulting medical condition called? The carbonic acid/hydrogen carbonate buffer system as the major buffer system responsible for controlling blood pH. H^+(aq) + HCO3^-(aq) <=> H2CO3(aq) <=> CO2(g) + H2O(l) When the equilibrium shifts to consume the additional CO2 in the blood as the result of respiratory depression, what happens to the blood pH? The pH increases because the equilibrium shifts to consume H^+. The pH decreases because the equilibrium shifts to consume H^+. The pH decreases because the equilibrium shifts to produce more H^+. The pH increases because the equilibrium shifts to produce more H^+.

Consider the following reaction: 3 H2(g) + N2(g) ⇌ 2 NH3(g) K=4.3 × 10^-4 Part 1 of 5 Write the expression for the equilibrium constant for this reaction. K=

(-3.4 × 10^4 μg/dL) · (10^-12 g/1 μ) × (1 dL/100 mL) F=? g/mL

Which compound is most likely to follow second-order kinetics in a substitution reaction? (A) CH3Br (B) (CH3)3CCH2Br (C) CH3CH2Br (D) (CH3)2CHBr

Atoms, Ions and Molecules Naming ionic compounds with common polyatomic ions Fill in the name and empirical formula of each ionic compound that could be formed from the ions in this table: Some ionic compounds cation anion empirical formula name of compound Na+ ClO2- NaClO2 K+ NO2- KNO2 Na+ ClO3- NaClO3

Draw the organic product you would expect to isolate from the nucleophilic substitution reaction between the molecules shown. Note: You do not need to draw any of the side products of the reaction, only the substitution product.

Question 14 3.35 Points You make a solution of a nonvolatile solute with a liquid solvent. Indicate if each of the following statements is true or false. (1) The freezing point of the solution decreases as the concentration of the solute increases. (2) The boiling point of the solution is independent of the concentration of the solute. (A) Both are true (B) Both are false C 1 is true while 2 is false (D) 1 is false while 2 is true

Question 12 3.35 Points If we touch a flask after urea was in the water in the flask, we will feel the flask is now cooler than it was before the urea was added. What can we say about this reaction between potassium and the water? A It is an endothermic reaction. (B) The value of ΔE is negative. C Heat from surrounds is absorbed by the system (D) The value for q in ΔE=q+w is negative (E) All the above are true F Only A and C are true

What is the IUPAC name of the following compound?

Nobelium, an element discovered in 1958, has a half-life of 10 min under certain conditions. In a sample containing 1 g of nobelium, the amount left after t min is given by A(t)=(0.5)^(t / 10). (Round to three decimal places.) (a) How much nobelium is left after 9 min? (b) How much nobelium is left after 1 h?

A typical atom has a size of about Q. 1 micrometers (10^-7 meters) Q. 1 nanometers (10^-10 meters) Q. 1 picometers (10^-13 meters)

Chemical Reactions Finding a molecular formula from molar mass and elemental analysis of binary... Compound X has a molar mass of 104.01 g/mol and the following composition: element - mass % nitrogen - 26.93 % fluorine - 73.07 % Write the molecular formula of X.

Dietary intake of what type of fat is most highly related to heart disease? Saturated Polyunsaturated Monounsaturated

What is an intermediate? - A local maximum on the energy diagram. - A point on the reaction pathway that has a discrete minima. - A point half-way between the starting materials and products. - The highest energy compound on an energy diagram.

proposed Lewis structure Is the proposed Lewis structure reasonable? [: O ≡ C-H]^+ Yes. No, it has the wrong number of valence electrons. The correct number is: No, it has the right number of valence electrons but doesn't satisfy the octet rule. The symbols of the problem atoms are:* [* * N-N= N ... *]^- Yes. No, it has the wrong number of valence electrons. The correct number is: No, it has the right number of valence electrons but doesn't satisfy the octet rule. The symbols of the problem atoms are:* * If two or more atoms of the same element don't satisfy the octet rule, just enter the chemical symbol as many times as necessary. For example, if two oxygen atoms don't satisfy the octet rule, enter "O,O".

This sketch is about 800 pm wide. The coordinate (x, y, and z) axes are also shown. You can rotate the sketch for a better view of the orbital by dragging the slider with your mouse. Suppose an atom with its nucleus at the origin has an electron in a 2 py orbital. Complete each row of the table below by deciding how PA, the probability of finding the electron at point A, compares to PB, the probability of finding the electron at point B. point A point B compare PA to PB

Follow the steps for graphing a rational function to graph the function F(x)=(x^2+5x-36)/(x+3). A. F(x)=((x+9)(x-4))/(x+3) (Type your answer in factored form. Do not simplify.) B. F(x) is already in factored form. What is the domain of F(x)? Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. x x ≠ -3 (Type an integer or a simplified fraction. Use a comma to separate answers as needed.) B. x x < (Type an integer or a simplified fraction.) C. x x ≥ (Type an integer or a simplified fraction.) D. The domain is the set of all real numbers. Write F(x) in lowest terms. Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. F(x)= (Simplify your answer.) B. F(X) is already in lowest terms.

What is the pH of an aqueous solution of 0.0654 M sodium hydroxide? pH=

A wooden artifact from an ancient tomb contains 45 percent of the carbon-14 that is present in living trees. How long ago, to the nearest year, was the artifact made? (The half-life of carbon-14 is 5730 years.) years

Question 6 A central atom has one single bond, one double bond, and two lone pair electrons. What is the molecular geometry for this atom? Bent Tetrahedral Trigonal pyramidal Linear

A magazine provided results from a poll of 1500 adults who were asked to identify their favorite pie. Among the 1500 respondents, 12% chose chocolate pie, and the margin of error was given as ± 5 percentage points. What values do p̂, q̂, n, E, and p represent? If the confidence level is 95%, what is the value of α? The value of p̂ is the sample proportion. The value of q̂ is found from evaluating 1-p̂. The value of n is the sample size. The value of E is the margin of error. The value of p is the population proportion.

What is the pH of a 0.024 M acetic acid (Ka=1.8 x 10^-5) solution at 25°C ?

Question 1 of 18 Use the Atomic Spectroscopy interactive to answer the question. Examine the spectra for the objects or substances in the list, and classify the type of spectrum produced by each. Absorption Continuous Emission Answer Bank hydrogen Sun neon light bulb

CH4 Part 3 of 3 □ neither □ covalent □ ionic

CH3-CH2-NH-C-CH3

3 t = how many mL?

In the reaction Zn + H^+ -> Zn^2+ + H2, Zn is oxidized and H is reduced. How many electrons would be produced and used in the balanced half-reactions? Complete the balanced half-reactions: H^+ + e^- -> H2 Zn -> Zn^2+ + e^-

When a solution of KOH is neutralized by hydrochloric acid, the solution gets hot. Calculate the change in heat of the solution (in J). Mass of combined solution 205 g Temperature change of the solution = 5.50 K Specific heat capacity of the solution = 4.18 J / g ⋅ K Give your answer to three significant figures.

Complete the table below. Round each of your entries to 2 significant digits. You may conjugate acid conjugate base ------------ formula Ka formula Kb 5.9 × 10^-6 C5H5N 1.7 × 10^-9 3.1 × 10^-8 ClO^- 3.3 × 10^-9 4.59 × 10^-7 HCO3 2.2 × 10^-8

What is the molarity of 2.0 moles of glucose in 4.0 L solution? A. 0.25 M glucose B. 0.50 M glucose C. 0.75 M glucose D. 1.00 M glucose

The state medical school has discovered a new test for tuberculosis. (If the test indicates a person has tuberculosis, the test is positive.) Experimentation has shown that the probability of a positive test is 0.78, given that a person has tuberculosis. The probability is 0.07 that the test registers positive, given that the person does not have tuberculosis. Assume that in the general population, the probability that a person has tuberculosis is 0.03. What is the probability that a person chosen at random will fall in the following categories. (a) have tuberculosis and have a positive test (b) not have tuberculosis (c) not have tuberculosis and have a positive test

For the unbalanced reaction below, calculate how many grams of potassium chloride form when 7.09 g of potassium chlorate completely reacts. Be sure to balance the reaction, use significant figures and units in the answer. KClO3(s) --> KCl(s) + O2(g)

Question 3 Which of the following conversions is not an example of oxidation Ketone to Secondary Alcohol Primary Alcohol to Aldehyde Aldehyde to Carboxylic Acid Secondary Alcohol to Ketone

Define the technologies that can clean up groundwater contamination. Items (3 items) (Drag and drop into the appropriate area below) pumping contaminants out of the ground materials that react with contaminants chemically transform them into safer, less soluble components injection of oxygen and nutrients to promote bacterial growth Categories perm. reactive barriers bioremediation extraction wells

Which of the following molecules contains high energy bonds? AMP CO2 Isocitrate ATP

A copper atom has a mass of 1.06 × 10^-22 g and a penny has a mass of 2.5 g. Use this information to answer the question below. Be sure your answers have the correct number of significant digits. What is the mass of 1 mole of copper atoms? Round your answer to 3 significant digits.

Balance the chemical equation given below, and determine the number of grams of MgO needed to produce 15.0 g of Fe2 O3. MgO(s)+ Fe(s) -> Fe2 O3(s)+ Mg(s)

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