Question

determine the mass of watervapor formed when 1.00g of butane, c4h10 is burned in a lighter.

Answer 1

The combustion equation should be 2C4H10 + 13O2 ----> 8CO2 + 10H2O
From this, 2 moles of c4h10 would produce 10 moles of water vapour
n(c4h10):n(h2o) = 1:5
If you find the moles of butane you have, you should be able to find the moles of water vapour produced
and then using the formula n=m/M, you can find the mass of the water vapour produced.