A 0.1592g sample of a hydrocarbon upon combustion analysis produces 0.5008g CO2. Its molar mass is found in another experiment to be 70g mol. Determine the empirical formula, and its molecular formula.

I completely messed up this question, and I don't know where I wen't wrong. My empirical formula: CH. The correct answer: CH2. Can someone help me how to get the right answer?

Oh sorry, the question also gives this information:the 0.2041g of H2O were also produced.

Sarah, why don't you show your work and let us find where you went wrong (instead of us working everything including what you did right and letting you check to see where we went right).

I figured out I went wrong when calculating the moles of hydrogen. I used the molar mass of just one hydrogen since I was calculating the moles of one mole of hydrogen. I didn't know that I had to 2X the g/mol of hydrogen. Is there an explanation why this is?

To determine the empirical formula and molecular formula of the hydrocarbon, we need to follow a series of steps. Let's break it down:

Step 1: Determine moles of CO2 produced
We know the mass of CO2 produced upon combustion analysis is 0.5008g. Since the molar mass of CO2 is 44g/mol (12g/mol for each carbon atom and 32g/mol for each oxygen atom), we can calculate the moles of CO2 using the formula:

moles = mass / molar mass
moles of CO2 = 0.5008g / 44g/mol ≈ 0.0114 mol CO2

Step 2: Determine moles of carbon (C) in the hydrocarbon
Since each mole of CO2 contains 1 mole of carbon atoms, we can assume that the moles of C in the hydrocarbon are equal to the moles of CO2:

moles of C = 0.0114 mol CO2

Step 3: Determine moles of hydrogen (H) in the hydrocarbon
To determine the moles of H, we need to subtract the moles of C from the total moles of the hydrocarbon. We know the molar mass of the hydrocarbon is 70g/mol, so we can calculate the moles of H:

moles of H = total moles - moles of C
moles of H = 70g/mol - 0.0114 mol ≈ 0.9886 mol H

Step 4: Determine the empirical formula
The empirical formula represents the simplest whole number ratio of atoms present in the compound. To find it, we need to divide the moles of each element by the smallest number of moles calculated.

Divide moles of C by the smallest number of moles (0.0114 mol):
moles of C empirical = 0.0114 mol / 0.0114 mol = 1

Divide moles of H by the smallest number of moles (0.0114 mol):
moles of H empirical = 0.9886 mol / 0.0114 mol ≈ 86.7

Round the ratio to the nearest whole number to obtain the empirical formula: CH

Step 5: Determine the molecular formula
The molecular formula represents the actual number of atoms of each element in a molecule. To find it, we need to know the molar mass of the compound. In this case, it is given as 70g/mol.

Calculate the molar mass of the empirical formula (CH):
molar mass of empirical formula = (12g/mol for C) + (1g/mol for H) = 13g/mol

Divide the molar mass of the hydrocarbon (70g/mol) by the molar mass of the empirical formula (13g/mol):
n = 70g/mol / 13g/mol ≈ 5.4

Round the ratio to the nearest whole number to obtain the subscripts for the molecular formula: C5H11

Thus, the empirical formula is CH, while the molecular formula is C5H11.

If your answer was CH instead of CH2, you might have incorrectly calculated the moles of H or made an error in one of the steps. Double-check your calculations to find the mistake.