which reactant in the reaction of sodium carbonate and calcium chloride dihydrate is the limiting reactant if 1.00 gram of each reagent is used?

a. sodium carbonate
b. calcium chloride dihydrate

1 answer

Most limiting reagent problems are done the same way.
1. Write the equation and balance it.
2a. Convert 1 g Na2CO3 to moles. moles = grams/molar mass.
2b. Convert 1 g CaCl2.2H2O to moles. same procedure.
3a. Using the coefficients in the balanced equation, convert moles Na2CO3 to moles CaCO3.
3b. Same procedure, convert moles CaCl2.2H2O to moles CaCO3.
3c. It is quite likely that moles from 3a and 3b will not be the same which means one of them is wrong. In limiting reagent problems, the correct answer is ALWAYS the smaller value and the reagent producing that value is the limiting reagent.
4. You aren't asked to calculate grams of the product, but you can convert the value from 3c to grams. g = moles x molar mass.