Answer to Question #78217 in General Chemistry for Lizy

Question

Methane burns in the air by the following reaction: CH4(g)+ 2O2(g)->CO2(g)+2H2O(g)
What mass of water is produces by burning 800.0g of methane?

Answer 1

CH4(g)+ 2O2(g)->CO2(g)+2H2O(g)

m (CH4) = 800 g
m (H2O) - ?

Answer: 1 800 g

(CH4): ν = 1 mol, Mr = 16 g/mol then m = 16 g
(H2O): ν = 2 mol, Mr = 18 g/mol then m = 36 g

We form the proportion:
CH4 - H2O
800 g - x g
16 g - 36 g

X = 800*36/16 = 1 800 g