Read the chemical equation.

mg + 2hcl → mgcl2 + h2

how many moles of mgcl2 are produced from 3 moles of hcl?

0.3
0.5
1.0
1.5

1.5 mol.

Explanation:

It is clear that 1.0 mol of Mg reacts with 2.0 moles of HCl to produce 1.0 mol of  MgCl₂ and 1.0 mol of H₂.

Using cross multiplication:

2.0 moles of HCl → 1.0 mole of MgCl₂.

3.0 moles of HCl → ??? mole of MgCl₂.

∴  The no. of moles of MgCl₂ are produced from 3.0 moles of HCl = (3.0 mol)(1.0 mol) / (2.0 mol) = 1.5 mol.

a:

by the combination of an unlimited number of elements