Complete combustion of 4.20 g of a hydrocarbon produced 13.4 g of CO2 and 4.81 g of H2O. What is the empirical formula for the hydrocarbon?
To determine the empirical formula of the hydrocarbon, we need to find the ratio of elements in the compound. In this case, we have the mass of carbon dioxide (CO2) and water (H2O) produced during combustion.
Let's start by finding the number of moles of CO2 and H2O produced:
- Moles of CO2 = mass of CO2 / molar mass of CO2
= 13.4 g / 44.01 g/mol
= 0.304 mol
- Moles of H2O = mass of H2O / molar mass of H2O
= 4.81 g / 18.02 g/mol
= 0.267 mol
Next, we need to find the ratio of moles between carbon and hydrogen. To do this, we divide the number of moles of each element by the smallest number of moles:
Carbon ratio = Moles of carbon / Smallest number of moles
= 0.304 mol / 0.267 mol
≈ 1.14
Hydrogen ratio = Moles of hydrogen / Smallest number of moles
= 0.267 mol / 0.267 mol
= 1
Since the carbon ratio is approximately 1.14 and the hydrogen ratio is 1, we can round these values to the nearest whole number:
Carbon ratio ≈ 1
Hydrogen ratio = 1
Therefore, the empirical formula of the hydrocarbon is CH.
find grams of C in CO2 and grams of H in H2O
convert the grams to moles (divide by the molar masses)
the mole ratio will give you the empirical formula