Assume that 5.60 L of hydrogen gas at STP reacts with copper (II) oxide
according to the following balanced equation. How many grams of copper are produced?

CuO (s) + H2 (g) --> Cu (s) + H2O (g)

15.9 grams of copper is produced

Explanation:

Step 1: Data given

Volume of hydrogen = 5.60 L ( at STP)

Step 2: The balanced equation

CuO (s) + H2 (g) → Cu (s) + H2O (g)

Step 3: Calculate moles H2

22.4 L = 1 mol

5.60 L =  0.25 moles

Step 3: Calculate moles Cu

For 1 mol CuO we need 1 mol H2 to produce 1 mol Cu and 1 mol H2O

For 0.25 moles H2 we'll have 0.25 moles Cu

Step 4: Calculate mass Cu

Mass Cu = moles Cu * molar mass Cu

Mass Cu = 0.25 moles * 63.546 g/mol

Mass Cu = 15.9 grams

15.9 grams of copper is produced

a is the correct answer