A hydrocarbon containing 88.9% carbon has the empirical formula [H = 1 C = 12]
Answer Details
To find the molecular formula of the hydrocarbon, we need to first determine its empirical formula. The empirical formula represents the simplest whole number ratio of atoms present in a compound. From the given data, we know that the hydrocarbon contains 88.9% carbon. This means that the remainder of the compound is made up of hydrogen. To calculate the empirical formula, we assume a 100g sample of the hydrocarbon. Therefore, the sample would contain 88.9g of carbon and 11.1g of hydrogen. Next, we convert the mass of each element to the number of moles using their respective atomic masses. The atomic mass of carbon is 12 g/mol, and that of hydrogen is 1 g/mol. The number of moles of carbon can be calculated as follows: moles of carbon = mass of carbon/atomic mass of carbon moles of carbon = 88.9g/12 g/mol moles of carbon = 7.41 mol Similarly, the number of moles of hydrogen can be calculated as follows: moles of hydrogen = mass of hydrogen/atomic mass of hydrogen moles of hydrogen = 11.1g/1 g/mol moles of hydrogen = 11.1 mol The empirical formula is then calculated by dividing the number of moles of each element by the smallest number of moles obtained in the previous step. This gives the simplest whole number ratio of the elements. The empirical formula for the hydrocarbon is therefore: C : H = 7.41 mol : 11.1 mol Dividing by 7.41 gives: C : H = 1 : 1.5 Therefore, the empirical formula for the hydrocarbon is CH1.5. We can round this up to CH2. The molecular formula can be determined by multiplying the empirical formula by a whole number n, which represents the number of empirical formula units in the compound. However, since we don't have any additional information about the hydrocarbon, we cannot determine the molecular formula with certainty. Therefore, the answer is (B) CH2, which represents the empirical formula of the hydrocarbon.