Question

What is the molarity of 750 mL of NaCl solution that contains 21.04 g of

NaCl?
The Periodic Table
A. 0.028 mol/L
B. 0.48 mol/L
C. 28 mol/L
D. 4.8 x 10-4 mol/L

Answer 1

Given:

volume of solution = 750 mL = 0.750 L

mass of solute = 21.04 g

solute: NaCl

Required:

molarity

Solution:

Step 1: Calculate the molar mass of solute.

molar mass of solute = (22.99 g/mol × 1) + (35.45 g/mol × 1)

molar mass of solute = 58.44 g/mol

Step 2: Calculate the number of moles of solute.

moles of solute = mass of solute / molar mass of solute

moles of solute = 21.04 g / 58.44 g/mol

moles of solute = 0.360027 mol

Step 3: Calculate the molarity.

molarity = moles of solute / volume of solution

molarity = 0.360027 mol / 0.750 L

molarity = 0.48 mol/L

Answer:

B. 0.48 mol/L

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