Question

-) How many moles of water will be produced by the complete combustion of 3

moles of propane (C₂H₂)?

Answer 1

6 moles of H2O

Step-by-step explanation:

We need the balanced equation for this reaction.

C2H2 + O2 = CO2 + H2O

2C2H2 + 5O2 = 2CO2 + 4H2O [Balanced reaction]

The balanced reaction tells us that we should expect to obtain 4 moles of water, H2), for every 2 moles of C2H2 (ethylene).

That is a ratio: (4 moles H2O)/(2 moles C2H2) or (2/1)(moles H2O/moles C2H4)

If we start with 3 moles of C2H4:

(3 moles C2H4)*((2 moles H2O)/(1 moles C2H2)) = (2*3/1) moles H2O [the moles C2H2 cancel]

(2*3/1) moles H2O = 6 moles of H2O