If you used 2.0mL of 1.0M H2SO4 and 3.0g of NaHCO3 how many moles of CO2 would be produced?

1 answer

This is a limiting reagent (LR) problem and we know that because amounts are given for BOTH reactants.

H2SO4 + 2NaHCO3 ==> Na2SO4 + 2H2O + 2CO2

mols H2SO4 = M x L = 0.002
mols NaHCO3 = g/molar mass = approx 0.036 but that's only an estimate and you should do all of these calculations over.

Now convert each to mols of the product.
First H2SO4:
0.002 mols H2SO4 x (2 mols CO2/1 mol H2SO4) = 0.004 mols CO2.

Then NaHCO3:
0.036 mols NaHCO3 x (2 mols CO2/2 mols NaHCO3) = 0.036 x (2/2) = 0.036 mols CO3.

The two numbers don't agree (they rarely do in LR problems) so one of them must be wrong; the correct value in LR problems is ALWAYS the smaller value and the reagent producing that value is the LR. So we will produce 0.005 mols CO2