Question

Determine the concentration of a solution (M) made by dissolving 18.8 g of sodium chloride (NaCl) in 750.0 mL of solution.

Answer 1

Answer:

0.429 M

Explanation:

To find the molarity, you need to (1) convert grams to moles (using the molar mass), then (2) convert mL to L, and then (3) calculate the molarity (using the molarity ratio).

(Step 1)

Molar Mass (NaCl): 22.990 g/mol + 35.453 g/mol

Molar Mass (NaCl): 58.443 g/mol

18.8 grams NaCl               1 mole
--------------------------  x  ------------------------  =  0.322 moles NaCl
                                     58.443 grams

(Step 2)

1,000 mL = L

 750.0 mL                1 L
------------------  x  -----------------  =  0.7500 L
                            1,000 mL

(Step 3)

Molarity (M) = moles / volume (L)

Molarity = 0.332 moles / 0.7500 L

Molarity = 0.429 M