Answer:
15 moles
Step-by-step explanation:
Data given:
mass of hydrogen (H₂) = 30.0 g
amount of oxygen (O₂) = excess
moles of water = ?
Solution:
First we look to the reaction in which hydrogen react with oxygen and make (H₂O)
Reaction:
2H₂ + O₂ -----------> 2H₂O
Now look at the reaction for mole ratio
2H₂ + O₂ -----------> 2H₂O
2 mole 2 mole
So it is 2:2 mole ratio of hydrogen to water
As we Know
molar mass of H₂ = 2(1) = 2 g/mol
molar mass of H₂O = 2(1) + 16 = 18 g/mol
Now convert moles to gram
2H₂ + O₂ -----------> 2H₂O
2 mole (2 g/mol) 2 mole (18 g/mol)
4 g 36 g
So,
we come to know that 4 g of hydrogen gives 36 g of water then how many grams of water will be produce by 30 grams of hydrogen.
Apply unity formula
4 g of H₂ ≅ 36 g of H₂O
30 g of H₂ ≅ X of H₂O
Do cross multiplication
X of H₂O = 30 g x 36 g / 4 g
X of H₂O = 270 g
Now convert grams of H₂O into moles
No. of moles = mass in grams/molar mass
Put values in above formula
No. of moles = 270 g / 18 (g/mol)
No. of moles = 15 mol
so 30 gram of hydrogen produce 15 mol of water.