Textbook problems

[Roxan Sheikh 3L]

When limestone, which is principally CaCO3, is heated, carbon dioxide and quicklime, CaO, are produced by the reaction CaCO3(s)→CaO (s)+CO2(g). If 17.5 g of CO2 is produced from the thermal decomposition of 42.73 g of
CaCO3, what is the percentage yield of the reaction?

I was just wondering if someone could break down this problem for me?

[Angela Denvir 1H]

Hi!
In order to find the percentage yield, you first need to convert the amount of CaCo3 to moles using the molar mass, 100.09 g/mol. Once you find the number of moles, you can conclude that the reaction should produce an equal number of moles of CO2. Therefore, you convert the number that you got for the moles of CaCO3 to grams. This will give you the theoretical yield. To find the percent yield, you divide the actual (experimental) yield by the theoretical yield and multiply by 100%.

Hope this helps!

[Vivian Kim 3F]

First thing that I do is see what is given to me. So we know that 17.5g of CO2 was produced. When it asks for a percent yield, we're looking at what is being produced. If 17.5 was the experimental result (actual yield), what we need to do is find the ideal amount of CO2 produced from 42.73g of CaCO3 (theoretical yield). Then we can find the percent yield by dividing them.

Steps:
1. convert 42.73 grams to moles : 42.73g / (100.088g/mol) = 0.43 mol
2. Find how much CO2 is produced (they have a 1:1 ratio) : 0.43 mol CaCO3 = 0.43 mol CO2
3. Convert to grams (so we can divide by the actual yield 17.5g): 0.43 mol x (44.01 g/mol) = 18.79g
4. Find percent yield by dividing the actual yeild (17.5g) by the theoretical yield (18.79g) : 17.5g / 18.79g = 93.1%