Answer :
Answer:
24.5g
Explanation:
Given parameters:
Mass of oxygen gas = 21.8g
Unknown:
Mass of water = ?
Solution:
This problem deals with the decomposition of water;
Reaction equation;
2H₂O → 2H₂ + O₂
2 mole of water will produce 1 mole of oxygen gas
First find the number of mole of the oxygen gas given;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
molar mass of O₂ = 2(16) = 32g/mol
Number of moles of O₂ = [tex]\frac{21.8}{32}[/tex] = 0.68moles
1 mole of oxygen gas will be produced from 2 mole of water
0.68moles of oxygen gas will be produce from 0.68 x 2 moles of water; = 1.36moles of water
Mass of water = number of moles x molar mass
Molar mass of water = 2(1) + 16 = 18g/mol
Mass of water = 1.36 x 18 = 24.5g