Question

Ethylene burns in oxygen to form carbon dioxide and water vapor:

C2H4(g)+ 3 O2(g)-->2 CO2(g)+ 2 H2O(g)

How many liters of water can be formed if 1.25 liters of ethylene are consumed in this reaction? (Assume STP)

_____ L H2O (3 sig figs)

Answer 1

1.25 L of C2H4 is equal to:

1.25 L / 22.4 L/mol = 0.0558 moles

From the balanced chemical equation, we see that for every 1 mole of C2H4 that reacts, 2 moles of H2O are formed.

So, for 0.0558 moles of C2H4:

0.0558 moles * 2 moles H2O/mole C2H4 = 0.1116 moles of H2O

0.1116 moles * 22.4 L/mol = 2.51 L H2O (3 sig figs)