Question

28.06 g of ethene (C2H4) gas is mixed with 147.84 g of oxygen (O2) gas. The mixture is ignited

Write the balanced chemical reaction for the combustion of ethene.

How many moles of water can you make?

How many moles of CO2 can you make?

Will anything be left over? (Which of the following: )

a) Yes, there will be ethene left over

b) Yes, there will be oxygen left over

c) No, there will be nothing left over

Answer 1

C₂H₄ + 3 O₂ -------------> 2 CO₂ + 2 H₂O

No. of moles of C2H4 = 28.06 / 28.05 = 1

no. of moles of O2 = 147.84 / 32 = 4.62 moles

from the balanced chemical equation, 1 mole of C2H4 will react with 3 moles of O2

Here excess is O2; so limiting reagent is C2H4

no. of moles of H2O formed = 2 moles

Weight of H2O formed = 2 x 18 = 36 grams

no. of moles of CO2 formed = 2 moles

Weight of CO2 formed = 2 x 44 = 88 grams.

b) Yes, Excess O2 oxygen left over

excess O2 = 4.62 - 3 =1.62 moles

Weight of excess O2 = 1.62 x 32 = 51.84 grams