Question

How many grams of HCl would be required to make 0.3 L of a 12.0 M solution?

A.25 g
B.146 g
C.131 g
D.40 g

Answer 1

The mass of HCl is 131 grams (option C)

Step-by-step explanation:

Step 1: Data given

Volume of solution = 0.3L

Molarity = 12.0 M

Molar mass of HCl = 36.46 g/mol

Step 2: Calculate moles HCl

Moles HCl = molarity * volume

Moles HCl = 12.0 M * 0.3L

Moles HCl = 3.6 moles

Step 3: Calculate mass of HCl

Mass HCl =moles HCl * molar mass HCl

Mass HCl = 3.6 moles * 36.46 g/mol

Mass HCl = 131.3 grams ≈ 131 grams

The mass of HCl is 131 grams (option C)

Answer 2

The molarity of a solution is the quotient obtained when number of moles is divided by volume.
molarity = n / V
Calculating for n,
n = (12)(0.3) = 3.6 moles
Then, we multiply the number of moles calculated by the molar mass of HCl which is equal to 36 g/mol.
mass = (3.6 moles)(36 g/mol) = 129.6 grams