Question

Ca(OH)2 + 2HNO3 -> Ca(NO3)2+ 2H2O How many moles nitric acid is needed to make 22.8 g of water?

Answer 1

Hey there!:

Molar mass:

HNO3 = 63.01 g/mol

H2O = 18.01 g/mol

By the stoichiometry of the reaction:

Ca(OH)2 + 2HNO3 -> Ca(NO3)2+ 2H2O

( 2 * 63.01 ) g HNO3 --------------- ( 2 * 18.01 ) g H2O

mass of HNO3 ---------------------- 22.8 g H2O

mass of HNO3 = ( 22.8 * 2 * 63.01 ) / (2 * 18.01 )

mass of HNO3 = 2873.256 / 36.02

mass of HNO3 = 79.768 g

Therefore:

1 mole HNO3 ------------------ 63.01 g

moles HNO3 ------------------ 79.768 g

moles HNO3 = ( 79.768 * 1 ) / ( 63.01 )

moles HNO3 = 79.768 / 63.01

=> 1.265 moles of HNO3

Hope that helps!

Answer 2

1.27 mol HNO₃

Explanation:

We know we will need a balanced chemical equation with masses, moles, and molar masses.

1. Gather all the information in one place:

M_r: 18.02

Ca(OH)₂ + 2HNO₃ ⟶ Ca(NO₃)₂ + 2H₂O

m/g: 22.8

2. Calculate the moles of H₂O

Moles of H₂O = 22.8 g H₂O × (1 mol H₂O/18.02 g H₂O)

= 1.265 mol H₂O

3. Calculate the moles of HNO₃

The molar ratio is 2 mol HNO₃/2 mol H₂O.

Moles of HNO₃ = 1.265 mol H₂O × (2 mol HNO₃/2 mol H₂O)

= 1.27 mol HNO₃