A compound of carbon, hydrogen, and oxygen was burned in oxygen, and 2.00g of the compound produced 2.868 g CO2 and 1.567 g H2O. In another experiment, 0.1107 g of the compound was dissolved in 25.0 g of water. This solution had a freezing point of -0.0894 degrees C. what is the molecular formula of the compound?
Your school's name is not the subject
To determine the molecular formula of the compound, we need to follow a step-by-step approach:
Step 1: Calculate the moles of CO2 and H2O produced.
We are given the mass of CO2 and H2O produced, so we can calculate the moles of each compound using their respective molar masses. The molar mass of CO2 is 44.01 g/mol, and the molar mass of H2O is 18.02 g/mol.
Moles of CO2 = mass of CO2 / molar mass of CO2
Moles of CO2 = 2.868 g / 44.01 g/mol
Moles of CO2 ≈ 0.0652 mol
Moles of H2O = mass of H2O / molar mass of H2O
Moles of H2O = 1.567 g / 18.02 g/mol
Moles of H2O ≈ 0.0869 mol
Step 2: Determine the empirical formula of the compound.
To find the empirical formula, we need to determine the simplest whole number ratio of the atoms present in the compound. We do this by dividing the moles of each element by the smallest number of moles obtained.
Empirical formula = CxHyOz
Mole ratio of carbon (C) to oxygen (O) = 0.0652 mol / 0.0652 mol = 1
Mole ratio of hydrogen (H) to oxygen (O) = 0.0869 mol / 0.0652 mol ≈ 1.329
Since the ratio of hydrogen to oxygen is not a whole number, we multiply all the ratios by 3 to obtain whole numbers:
Mole ratio of carbon (C) to oxygen (O) = 3
Mole ratio of hydrogen (H) to oxygen (O) ≈ 4
Empirical formula = C3H4O
Step 3: Calculate the molar mass of the empirical formula.
The molar mass of the empirical formula can be calculated by multiplying the molar mass of each element by its respective subscript and summing them all.
Molar mass of C3H4O = (molar mass of C × 3) + (molar mass of H × 4) + (molar mass of O × 1)
Molar mass of C3H4O = (12.01 g/mol × 3) + (1.01 g/mol × 4) + (16.00 g/mol × 1)
Molar mass of C3H4O = 36.03 g/mol + 4.04 g/mol + 16.00 g/mol
Molar mass of C3H4O ≈ 56.07 g/mol
Step 4: Calculate the number of empirical formula units in the compound.
The number of empirical formula units can be determined by dividing the experimental mass of the compound by the molar mass of the empirical formula.
Number of empirical formula units = mass of compound / molar mass of C3H4O
Number of empirical formula units = 0.1107 g / 56.07 g/mol
Number of empirical formula units ≈ 0.00197 mol
Step 5: Determine the molecular formula.
To find the molecular formula, we need to determine the number of empirical formula units in the compound.
Number of empirical formula units = 0.00197 mol
Number of empirical formula units ≈ 2 empirical formula units
Therefore, the molecular formula of the compound is 2 times the empirical formula: C6H8O2.