Question

The rubbing alcohol i just bought is marked 77% CH,OH. If burned 50.0 grams of this alcohol, how many grams of carbon dioxide would form, assuming the other 23.00% is not organic?

Answer 1

73.56 g CO₂

Procedure

To solve this exercise first consider the following ethanol combustion equation

C₂H₅OH(l)+3O₂(g)⟶2CO₂(g)+3H₂O(l)

Assuming that the oxygen supply is unlimited as there is no data regarding oxygen, ethanol will be our limiting reactant.

Convert from grams to moles to be able to use the equation

`50g\text{ }C₂H₅OH\frac{1\text{ }mole}{46.07g}=1.085\text{ }mole\text{ }C₂H₅OH`

Using the proportions given by the combustion equation

Converting back to grams of CO2

`2.17\text{ }mole\text{ }CO₂\frac{44.01g}{1\text{ }mole}=95.5285g\text{ }CO₂`

Adjusting for the yield

`95.5285gCO_{2\text{ }}(77)/(100)=73.56g\text{ }CO_2`