Question

If 72.5 grams of calcium metal (Ca) react with 65.0 grams of oxygen gas (O2) in a synthesis reaction, how many grams of the excess reactant will be left over when the reaction is complete?

Be sure to write out the balanced equation for this reaction and to show all of your work.

Answer 1

Well, we cannot do all the work. However, what can you understand from this?

Answer 2

first write out the equation

Ca + O2 --> CaO *** this equation is NOT balanced so you will have to balance the coefficients

from there, convert g of reactants to moles
then you need to find out which reactant (Ca or O2) is limited. calculate how many moles of CaO that each reactant would produce w/ stoichiometry. the reactant that gives you the lower product moles is the limiting reactant

from there, the other reactant is the reactant that will be in excess. calculate how much of that reactant you use, and subtract that from the original amount of reactant

lmk if you have trouble b/c this is a lot to take in at once