Question

2H2 + O2 -> 2H2O
How many grams of O2 and H2 were reacted to produce 30.0 g of H2O?

Answer 1

@hartnn

Answer 2

@iambatman @nincompoop @Loser66

Answer 3

@Preetha @hba @tHe_FiZiCx99 @aaronq @BioEpic @prowrestler

Answer 4

\[2H_2+O_2\rightarrow 2H_2O\]
As you can see, \(n_{H_2}=2n_{O_2}=n_{H_2O}\)

First, calculate the amount of \(H_2O\). Now you get \(n_{H_2}=n_{H_2O}\), \(n_{O_2}=\frac{1}{2}n_{H_2O}\). You can easily calculate the mass of \(H_2\) and \(O_2\).

Answer 5

what do you mean by calculate the amount of H2O? Would that be 30g?

Answer 6

It is the amount of \(H_2O\) in moles. \(n=\frac{m}{M}\)

Answer 7

so 1.7 moles of H2O

Answer 8

Yes, about \(\frac{5}{3}\).

Answer 9

and now what do i do?

Answer 10

\(n_{H_2}=n_{H_2O}\)

Answer 11

would it be 1.7 mol H2 and 0.85 mol O2? :/

Answer 12

Correct. :)

Answer 13

so i would change that to grams by multiplying by the mass of H2 and O2?

Answer 14

Yes, the molar mass M.

Answer 15

Would it be
1.7mol H2 x 1g = 1.7g H2
0.85mol O2 x 16g = 13.6g O2

or
1.7mol H2 x 2g = 3.4g H2
0.85mol O2 x 32g = 27.2g O2

Answer 16

Actually the second one is correct. A hydrogen molecule is formed by two H atoms.

Answer 17

ok thank you.

Answer 18

It's my pleasure :)

Answer 19

Good explanation there tinyworm!

Answer 20

Thank you, @Preetha.