Question

Passing an electric current through a sample of water (H2O) can cause the water to decompose into hydrogen gas (H2) and oxygen gas (O2) according to the following equation.

2H2O mc026-1.jpg 2H2 + O2

The molar mass of H2O is 18.01 g/mol. The molar mass of O2 is 32.00 g/mol. What mass of H2O, in grams, must react to produce 50.00 g of O2?

Answer 1

d on edge

Step-by-step explanation:

Answer 2

`2H_(2) O _((l)) -------\ \textgreater \ 2H_(2) _((g)) + O_(2) _((g))`

moles of oxygen in reaction =
`(mass)/(molar mass)`

=
`(50.00 g)/(32.00 g / mol)`

= 1.563 mol

Mole Ratio of oxygen to water in the reaction = 1 : 2
∴ for every mole of oxygen there is two moles of water

Thus moles of water in the reaction = (moles of oxygen) * 2
= 1.563 mol * 2
= 3.126 mol

Mass of water needed to produce amount of O = mol * molar mass
= (3.126 mol) * (18.01 g/mol)
= 56.299 g
≈ 56. 3 g