Answer to Question #162379 in Chemistry for Ava Brooke

Question

Using the following chemical equation how many grams of hydrochloric acid (HCl) are consumed reacting with 20.43 g of calcium hydroxide?

2HCl + Ca(OH)₂ -> 2H₂O + CaCl₂

Answer 1

Solution:

The balanced chemical equation:

Ca(OH)₂ + 2HCl → CaCl₂ + 2H₂O

According to the equation above: n(Ca(OH)₂) = n(HCl)/2

Moles of Ca(OH)₂ = Mass of Ca(OH)₂ / Molar mass of Ca(OH)₂

The molar mass of Ca(OH)₂ is 74.093 g mol^-1.

Hence,

n(Ca(OH)₂) = 20.43 g / 74.093 g mol^-1 = 0.2757 mol

n(HCl) = 2 × n(Ca(OH)₂) = 2 × 0.2757 mol = 0.5514 mol

Moles of HCl = Mass of HCl / Molar mass of HCl

Mass of HCl = Moles of HCl × Molar mass of HCl

The molar mass of HCl is 36.458 g mol^-1.

Hence,

m(HCl) = 0.5514 mol × 36.458 g mol^-1 = 20.1029 g = 20.10 g

Answer: 20.1 grams of hydrochloric acid (HCl) are consumed.