Question

how many grams of oxygen are required to completely react with 0.2g of hydrogen to produce water? also calculate how many moles of water is formed.

Answer 1

$2H_{2}+O_{2} ---\ \textgreater \ 2 H_{2}O$
molar mass of H2 = 2g
molar mass of O2 = 32g
Implies that 2 x 2g = 4g of hydrogen react with 32g of oxygen for producing water
Implies that 2 g of hydrogen reacts with 16 g of oxygen
So 0.2g of hydrogen reacts with 1.6 g of Oxygen.