Question

Given the reaction 2 H2 + O2 → 2 H2O, how many moles of oxygen would be consumed if 460 g of water were produced?
5.6 mol
12.8 mol
23.9 mol
46.1 mol

Answer 1

Answer:

12.8 mol

Explanation:

Hello,

In this case, given the reaction, one should use the molar mass of water that is 18 g/mol in order to perform the following stoichiometric calculation wherein the oxygen to water molar ratio is 1:2 respectively:

$n_{O_2}=460gH_2O*\frac{1molH_2O}{18gH_2O}*\frac{1molO_2}{2molH_2O} \\ \\n_{O_2}=12.8molO_2$

Best regards.

Answer 2

Answer:

13.14 moles of oxygen would be consumed if 460 g of water were produced

Explanation:

First of all you must know the molar mass of the compounds that participate in the reaction. Being:

• H: 1 g/mole
• O: 16 g/mole

The molar mass of the reactants and products in the reaction are:

• H₂: 2* 1 g/mole= 2 g/mole
• O₂: 2* 16 g/mole= 32 g/mole
• H₂O: 2* 1 g/mole + 16 g/mole= 18 g/mole

Now, by stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), they react and are produced:

• H₂: 2 moles
• O₂: 1 mole
• H₂O: 2 moles

Then, stoichiometry reacts 2 moles * 18 g/mole = 36 g of H₂O.

Then you can apply the following rule of three: if 35 grams of H₂O are formed from 1 mole of O₂, 460 grams of H₂O from how many moles of O₂ are formed?

$moles of O_{2} =\frac{460 grams of H_{2}O*1 mole of O_{2} }{35 grams of H_{2}O}$

moles of O₂= 13.14

13.14 moles of oxygen would be consumed if 460 g of water were produced