Question

Hydrogen and oxygen combined in the ratio of 1:8by mass to form water what mass of oxygen gas would be required to react completely with 3gram of hydrogen gas

Answer 1

Hydrogen and oxygen combine in the ratio of 1:8 means that 1g of hydrogen gas requires 8g of oxygen gas to form water.

Therefore, 3g of Hydrogen gas will require = 8 * 3 = 24 g of oxygen

Thus, 24g of the oxygen gas would be required to react completely with 3g of hydrogen gas to form water.