Stoichiometry Help!?

Question

Help!

1. Water is decomposed into Hydrogen (H2) gas and oxygen (O2) gases according to the following balanecd chemical equation. Answer the questions below regarding what would be produced if 0.50 moles of h20 undergoes decomposition:

2 H^2O(l) ---> 2 H^2(g) + O2(g)
(A) how many moles of 02 are produced when 0.50 moles of water are decomposed
(B) how many grams of H2 are produced when 0.50 moles of water are decomposed?

Answer 1

A) you see 2 moles of H2O correspond to 1 mole of O2
so answer of 1) 0.25 mole of O2

B) 0.5 mole Of H2 so 1 g of H2

Answer 2

A. Divide through by 2 which reveals 1 mole of H2O yields 1/2 mole oxygen. Therefore, 0.50 moles H2O yields 0.25 moles oxygen.

B. One mole of H2 per mole of H2O, therefore, there's 0.50 moles H2 from 0.5 mole water. Molecular wt of H2 is 2.0 thus you have 1.0 g.

Answer 3

1) Observe your balanced equation:

2 H2O(l) ---> 2 H2(g) + O2(g)

You can see that 2 moles of water produce 1 mol of oxygen hence:

0.5 moles of H2O produce 0.25 moles of oxygen (relation 2:1)

In the case of hydrogen apply the same:

2 moles of water produce 2 moles of H2,
hence, 0.5 moles of H2O produce 0.5 moles of H2

mass H2 = (0.5 moles H2) x (2 g/mol H2 ) = 1 gram of H2

That's it!
Good luck!