Question

What mass of water can be obtained from 4.0 g of H2 and 16 g of O2?

2 H2 + O2 ---> 2 H2O


18 g
36 g
54 g
9 g

Answer 1

Answer:

18 grams of water, will be produced from 4 g of H₂ and 16g of O₂

Explanation:

Reaction: 2H₂ + O₂  ⇒  2H₂O

Moles = Mass / Molar mass

Molar mass H₂ = 2g/m

Molar mass O₂ = 32 g/m

4g /2g/m = 2moles

16g / 32 g/m = 0.5 moles

Ratio is 2:1

For 2 moles of hydrogen, I need 1 mol of oxygen; I have 2 moles of H₂, but I only have 0.5 of O₂, so the O₂ is the limiting reagent.

1 mol of O₂ produces 2 mol of water

0.5 moles of O₂ will produce, the double → 1 mol of water.

Molar mass of water is 18 g/m

1 mol . 18 g/m = 18 g