Question

How many grams of water vapor is produced by burning 78 g of ethine?

Answer 1

1 mole of $C_2H_2$ =2(12.0)+2(1.0)=26g

1 mole of $H_2O$ =2(1.0)+16.0=18.0g

$=\frac{78g ×1 mole} {26g}$ = 3 mol $C_2H_2$

$=\frac{3.0 mol C_2H_2×2 H_2O}{ 2 C_2H_2} =3.0 mol H_2O$

=3mol $H_2O$ ×18.0g

=54g of water vapor.