Questions: What is the concentration (M) of a NaCl solution prepared by dissolving 9.3 g of NaCl in sufficient water to give 350 mL of solution? (A) 18 (B) 0.16 (C) 0.45 (D) 27 (E) 2.7 x 10^-2

What is the concentration (M) of a NaCl solution prepared by dissolving 9.3 g of NaCl in sufficient water to give 350 mL of solution?
(A) 18
(B) 0.16
(C) 0.45
(D) 27
(E) 2.7 x 10^-2

Transcript text: What is the concentration (M) of a NaCl solution prepared by dissolving 9.3 g of NaCl in sufficient water to give 350 mL of solution? (A) 18 (B) 0.16 (C) 0.45 (D) 27 (E) $2.7 \times 10^{-2}$

Solution

Solution Steps

Step 1: Calculate the Molar Mass of NaCl

To find the concentration, we first need to determine the molar mass of NaCl. The molar mass is the sum of the atomic masses of sodium (Na) and chlorine (Cl).

\[ \text{Molar mass of NaCl} = \text{Atomic mass of Na} + \text{Atomic mass of Cl} = 22.99 \, \text{g/mol} + 35.45 \, \text{g/mol} = 58.44 \, \text{g/mol} \]

Step 2: Convert Grams of NaCl to Moles

Next, we convert the mass of NaCl (9.3 g) to moles using the molar mass.

\[ \text{Moles of NaCl} = \frac{\text{Mass of NaCl}}{\text{Molar mass of NaCl}} = \frac{9.3 \, \text{g}}{58.44 \, \text{g/mol}} = 0.1591 \, \text{mol} \]

Step 3: Convert Volume of Solution to Liters

The volume of the solution is given in milliliters (350 mL). We need to convert this to liters.

\[ \text{Volume in liters} = \frac{350 \, \text{mL}}{1000 \, \text{mL/L}} = 0.350 \, \text{L} \]

Step 4: Calculate the Molarity of the Solution

Molarity (M) is defined as the number of moles of solute per liter of solution.

\[ \text{Molarity} = \frac{\text{Moles of NaCl}}{\text{Volume of solution in liters}} = \frac{0.1591 \, \text{mol}}{0.350 \, \text{L}} = 0.4546 \, \text{M} \]