Complete combustion of 8.00 g of hydrocarbon produced 26.0g of CO2 and 7.99g of H2O. What is the empirical formula for the hydrocarbon?
To find the empirical formula of the hydrocarbon, we need to determine the ratio of the elements in the compound.
First, let's calculate the number of moles of carbon dioxide (CO2) and water (H2O) produced from the given mass:
Molar mass of CO2 = 12.01 g/mol + 2 * 16.00 g/mol = 44.01 g/mol
Molar mass of H2O = 2 * 1.01 g/mol + 16.00 g/mol = 18.02 g/mol
Number of moles of CO2 = 26.0 g / 44.01 g/mol = 0.59 mol
Number of moles of H2O = 7.99 g / 18.02 g/mol = 0.44 mol
Next, let's determine the number of moles of carbon and hydrogen in the hydrocarbon.
For each mole of CO2 produced, there is 1 mole of carbon.
So, the number of moles of carbon in the hydrocarbon is 0.59 mol.
For each mole of H2O produced, there is 2 moles of hydrogen.
So, the number of moles of hydrogen in the hydrocarbon is 2 * 0.44 mol = 0.88 mol.
The empirical formula of the hydrocarbon will have the simplest whole number ratio of carbon to hydrogen.
To find this ratio, divide the number of moles of carbon and hydrogen by the smallest value:
Carbon: Hydrogen = 0.59 mol / 0.59 mol : 0.88 mol / 0.59 mol
= 1 : 1.49
Since we want whole numbers, we can multiply the ratio by 2 to get rid of the decimal:
Carbon: Hydrogen = 2 : 2.98
Now, approximate the ratio as the simplest whole number ratio:
Carbon: Hydrogen = 1 : 1.5
The empirical formula of the hydrocarbon is CH1.5, but this ratio should be multiplied by 2 to get whole numbers:
Empirical formula of the hydrocarbon = C2H3
To find the empirical formula of a hydrocarbon, we need to determine the ratio of carbon and hydrogen atoms present in the compound.
Let's start by determining the number of moles of CO2 and H2O produced:
Number of moles of CO2 = mass of CO2 / molar mass of CO2
Number of moles of H2O = mass of H2O / molar mass of H2O
Using the molar masses of CO2 (44.01 g/mol) and H2O (18.02 g/mol), we get:
Number of moles of CO2 = 26.0 g / 44.01 g/mol ≈ 0.590 mol
Number of moles of H2O = 7.99 g / 18.02 g/mol ≈ 0.443 mol
Next, we need to find the lowest whole number ratio of carbon to hydrogen. To do this, we divide the number of moles of each element by the smallest number of moles (in this case, moles of H2O):
Carbon ratio = 0.590 mol / 0.443 mol ≈ 1.33
Hydrogen ratio = 0.443 mol / 0.443 mol = 1
Now, we need to convert these ratios to whole numbers. To do this, we can multiply both ratios by a factor that will make the hydrogen ratio equal to 1. The hydrogen ratio is already 1, so we only need to multiply the carbon ratio by 1.
Carbon ratio: 1.33 ≈ 4/3
Hydrogen ratio: 1
After multiplying the carbon ratio by 3, we get:
Carbon ratio: 4
Hydrogen ratio: 3
Therefore, the empirical formula of the hydrocarbon is CH4.