Question

How many moles of HF acid are there in an 80g sample?

Answer 1

Answer:
3.98 mol

Solution:
Moles and mass is related to each other as follow,

Moles = Mass / M.mass ------ (1)

Data Given:
Mole = ?

Mass = 80 g

M.mass = 20.07 g/mol ∴ (H = 1.08 g/mol) + (F = 18.99 g/mol)

Putting values in equation 1,

Mole = 80 g ÷ 20.07 g.mol⁻¹

Mole = 3.98 mol