#Zn(s) + 2HCl(aq) -> H_2 (g) + ZnCl_2(aq) + #heat energy. If 30.0 g of #Zn# react, how many grams of #H_2# will form?

1 Answer
Jul 2, 2016

Answer:

1.85 g of hydrogen will form.

Explanation:

1. Write the balanced equation.

#"Zn" + "2HCl" → "ZnCl"_2 + "H"_2#

2. Calculate the moles of #"Zn"#.

#"Moles of Zn" = 30.0 color(red)(cancel(color(black)("g Zn"))) × ("1 mol Zn")/(65.38 color(red)(cancel(color(black)("g Zn")))) = "0.4589 mol Zn"#

3. Calculate the moles of #"H"_2#.

#"Moles of H"_2 = 0.4589 color(red)(cancel(color(black)("mol Zn"))) × ("2 mol H"_2)/(1 color(red)(cancel(color(black)("mol Zn")))) = "0.9177 mol H"_2#

4. Calculate the mass of #"H"_2#.

#"Mass of H"_2 = 0.9177 color(red)(cancel(color(black)("mol H"_2))) × ("2.016 g H"_2)/(1 color(red)(cancel(color(black)("mol H"_2)))) = "1.85 g H"_2#