chemistry question

Question

how much H2O will be produced if 25.4 g LiOH reacts with 64.8 g CO2? 

Answer 1

Let's look at the balanced equation for this reaction:

2LiOH + CO₂ ==> Li₂CO₃ + H₂O .. balanced equation

Now we can use the stoichiometry of this equation (mole ratios) to solve the problem. But first, we must of course convert g to moles and since we are given the amounts of BOTH reactants, we must find which, if either, is limiting.

Required info:

molar mass LiOH = 23.95 g / mol

molar mass CO₂ = 44.0 g / mol

molar mas H₂O = 18.0 g / mol

One easy way to find the limiting reactant is to simply divide the moles of each reactant the the corresponding coefficient in the balanced equation. Whichever value is less indicates the limiting reactant. Thus ..

For LiOH we have: 25.4 g LiOH x 1 mol LiOH / 23.95 g = 1.06 mols (÷2->0.53)

For CO₂ we have: 64.8 g CO₂ x 1 mol CO₂ / 44.0 g = 1.47 mols (÷1->1.47)

Since 0.53 is less than 1.47, LiOH is the limiting reactant, and the moles of LiOH (1.06 mols) will determine how much H₂O is formed.

Theoretical yield of H₂O = 1.06 mols LiOH x 1 mol H₂O / 2 mol LiOH x 18.0 g H₂O/mol = 9.54 g H₂O formed