Question

What is the mass of hydrogen produced from the reaction of 2.31 grams of HCl with magnesium?

Answer 1

HCl + Mg2 ---> H2 + MgCl2

4HCl + Mg2 = 2H2 + 2MgCl2
4mol 2mol
2.31gr ?gr

HCl mole = 2.31/(1.008+35.45)=0.06 mol

4HCl/1H2

0.06mol HCl x (1molH2/4molHCl)= 0.015mol H2

mass of H2 = 0.015 x (2*1.0008) =0.03gram H2

i think that's how it works.. plz check your answer

Answer 2

The equation is
Mg + 2HCl ==> H2 + MgCl2

Convert 2.31 g HCl to mols. mols = g/molar mass.

Convert mols HCl to mols H2 using the coefficients in the balanced equation.

Convert mols H2 to grams.
grams = mols H2 x molar mass H2.
Post your work if you get stuck.