Question

Consider the following balanced chemical equation representing the combustion of propane gas:

C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g)


The data from an experiment showed that 16.3 grams of carbon dioxide were produced. How many moles of water were expected as product? Report your answer with 3 SFs. Do NOT enter units on the final answer.


______________________ moles of H2O

Answer 1

We are given the following equation:

C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g)

we can see that the number of moles of H2O is 4/3 time the moles of CO2

So, the easiest way to find the number of moles of H2O is to find the number of moles of CO2 and multiply it by 4 / 3

Moles of CO2:

Molar mass of CO2 = 44 grams / mol

Moles of CO2 = Given mass / Molar mass

Moles of CO2 = 16.3 / 44 moles

Moles of H2O:

Moles of H2O = Moles of CO2 * 4 / 3

Moles of H2O = 16.3 * 4 / 3 * 44

Moles of H2O = 16.3 / 3 * 11

Moles of H2O = 16.3 / 33

Moles of H2O = 0.5 moles (approx)

Therefore, along with 16.3 grams of CO2, 0.5 moles of H2O will also be formed