Question

Consider the following reaction:
CaCN2 + 3H2O ¨ CaCO3 + 2NH3
105.0 g CaCN2 and 78.0 g H2O are reacted. Assuming 100% efficiency, which reactant is in excess and how much is leftover? The molar mass of CaCN2 is 80.11 g/mol. The
molar mass of CaCO3 is 100.09 g/mol.
1. H2O; 70.8 g left over
2. H2O; 10.7 g left over
3. CaCN2; 10.7 g left over
4. H2O; 7.20 g left over
5. CaCN2; 7.20 g left over
6. CaCN2; 70.8 g left over

I'm not getting any of these answers. I think H20 is in excess, but I get about 54 g for the amount.

Answer 1

Is that CaCN2 or Ca(CN)2. That may be your problem.

Answer 2

CaCN2

Answer 3

You're right. Water is in excess and a quick calculation I get 7.15 remaining; therefore, I would pick 4 a the answer.

Answer 4

H2O; 7.20 g left over