2 H2 + O2 → 2 H2O How many grams of water can be formed from 5.96 moles of oxygen gas?

Answer 1

Since the equation is balanced you can see the ratio of moles of Oxygen to H₂O is 1 to 2.

The moles of Oxygen is given as 5.96, so multiplying it by 2 will give you the moles of H₂O

5.96 mol O₂ x 2 mol H₂O = 11.92 mol H₂O

1 mol O₂

The answer is asked for in grams, so you need to calculate the molar mass of H₂O. Looking at the periodic table, the following masses are given for H and O

H = 1.008

O = 15.999

In H₂O there are two Hydrogen atoms and one Oxygen atom, so multiply the mass of Hydrogen by two and add it two the mass of Oxygen to get the molar mass of H₂O.

2(1.008) + 15.999 = 2.016 + 15.999 = 18.015 g/mol

Now you have the information you need to convert moles to grams.

11.92 mol H₂O x 18.015 g H₂O = 214.74 g H₂O

1 mol H₂O

Answer 2

Hello, Lily,

The balanced equation promises that we'll get 2 moles of water for every one mole of O₂. Since we start with 5.96 moles of O₂, we should expect 2x5.96 moles of H₂O.

11.92 moles of H₂O isn't very exciting, but it will be clear and pure. Convert to grams H₂O by multiplying by water's molar mass of 18g/mole. I get 214.6 grams H₂O. Round to 215 grams for 3 sig figs.

Bob