How many grams of CaO will be produced after 12.25 g of Ca are comlpetely decomposed?

Question

CaCO3→ CaO + CO2

Answer 1

You mean after CaCO3 decomposes.

Use the molar mass of CaCO3 to find the moles of CaCO3 and relate the moles of CaO to the moles of CaCO3. Then use the molar mass of CaO to find the mass of CaO.

There are 2 methods:

1. dimersional analysis which takes about 1 line

g CaCO3 x molar mass of CaCO3 (inverse) x mol CaO/ mol CaCO3 x molar mass of CaO

2. step by step wise way that will waste about 6 lines of paper

gCaCO3 x molar mass of CaCO3 (inverse) = moles of CaCO3

moles of CaCO3 x (mol CaO/ mol CaCO3) = mol CaO

mol CaO x molar mass of CaCO3 = g of CaCO3

I'll compute the answer using the first method:

(12.25 g CaCO3)(mol CaCO3/ 100 g CaCO3)(1 mol CaO/ 1 mol CaCO3)(56 g CaO/ 1 mol CaO) = 6.86 g CaO