How many grams of oxygen gas are reacted if 75 g of hydrogen gas is consumed?

Answer 1

Start from the equation for the reaction

O2 + 2H2 -> 2H2O

so 1 mole of O2 reacts with 2 moles of H2.

75 g of H2 gas contains

75 g/2 g mole^-1 = 37.5 mole

this will react with 37.5 mole/2 moles of O2 (from the equation)

hence calculate the number of grams of O2 gas (molar mass = 32 g mole^-1)