Question

How many moles of H2O form when 4.5 moles O2 reacts?

Answer 1

When 4.5 moles of O2 react, 9 moles of H2O are formed.

Step-by-step explanation:

The balanced reaction equation for the formation of water from oxygen is:

`2 H2(g) + O2(g) → 2 H2O(g)`

From the balanced equation, we can see that 2 moles of water are formed for every mole of oxygen consumed.

To find the number of moles of water formed when 4.5 moles of O2 react, we can use the mole ratio given by the balanced equation. The mole ratio is 2 moles of H2O : 1 mole of O2.

Therefore, we can calculate the number of moles of H2O formed as:

(4.5 moles O2) × (2 moles H2O / 1 mole O2) = 9 moles H2O

Answer 2

Step-by-step explanation:

Start with a balanced equation.

2H2 + O2 → 2H2O

Assuming that H2 is in excess, multiply the given moles H2O by the mole ratio between O2 and H2O in the balanced equation so that moles H2O cancel.

5 mol H2O × (1 mol O2/2 mol H2O) = 2.5 mol O2

Answer: 2.5 mol O2 are needed to make 5 mol H2O, assuming H2 is in excess.