For the reaction, calculate how many moles of the product form when 2.45 mol of O2 completely reacts. Assume that there is more than enough of the other reactant. 2H2(g)+O2(g)→2H2O(l)

Answer 1

Sam,

This looks like a limited reagent problem but it tells you which one is limiting which is O_2.

You will need to use stoichiometry to complete this question.

Given : 2.45 mol O₂ and the stoichiometric ratio has to be moles of O₂ to moles of the product H₂O

The ratio is found by looking at the coefficients in front of the oxygen and water. There is no number in front of oxygen which means the coefficient is 1. Just like when you see "x" in an algebra problem, it means there is 1x. The number in front of water is 2.

You are going from moles of oxygen to moles of water so I would write the work out like this:

2.45 moles O₂ x 2 moles H₂O/ 1 mole O₂

moles of water is on top because the moles of oxygen cancel when you complete the math which gives you

(2.45 x 2) / 1 = 4.9 moles of H₂O

Answer 2

The mole ratio of O2 to H2O is 1:2. Thus...

2,45 moles O2 x 2 moles H2O/mole O2 = 4.9 moles H2O