• A compound is known to contain only C, H, and N.

• On combustion of a sample of 12.5 mg, 22.3 mg of CO2 and 15.2 mg of H2O were produced.
•Use this data to find the empirical formula for the compound. (Please show working out)

12.5 mg C,H,N.

Convert mg CO2 to mg C.
22.3 CO2 x (1 mol/molar mass CO2) x (12 g C/1 mol) = about 0.5 mg C (but you should do it more accurately.
Do the same for H2O to hydrogen.
15.2 mg H2O x ( mol H2O/molar mass H2O)x (2 g H2/1mol H2) = about 1.7 mg H.
12.5 mg total - mg CO2 - mg H = mg N = about 0.34 mg.

Then convert mg to mols (I would use millimols).
0.5/12 = millimols C
1.7/1 = mmoles H
0.34/14 = mmoles N.

Now find the ratio of these elements to each other in small whole numbers. The easy way to do that is to divide the smallest number by itelf then divide the other two numbers by the same small number. Round to whole numbers BUI don't round too much; i.e., 5.9 can be called 6.0 but 1.5 can't be rounded to 1 or 2.

To find the empirical formula for the compound, we need to determine the ratio of the elements present in the compound based on the given data.

1. Start by calculating the mass of carbon (C) and hydrogen (H) in the compound:
- Mass of CO2 produced: 22.3 mg
- Carbon dioxide (CO2) consists of one carbon atom and two oxygen atoms.
- The atomic mass of carbon (C) is 12.01 g/mol, and the molecular mass of CO2 is 44.01 g/mol.
- Therefore, the mass of carbon (C) in the CO2 produced is: (12.01 g/mol / 44.01 g/mol) * 22.3 mg = X.

- Mass of H2O produced: 15.2 mg
- Water (H2O) consists of two hydrogen atoms and one oxygen atom.
- The atomic mass of hydrogen (H) is 1.01 g/mol, and the molecular mass of H2O is 18.02 g/mol.
- Therefore, the mass of hydrogen (H) in the H2O produced is: (2 * 1.01 g/mol / 18.02 g/mol) * 15.2 mg = Y.

2. Next, calculate the mass of nitrogen (N) in the compound:
- Since the mass of nitrogen (N) was not provided, we need to determine it indirectly.
- The total mass of the compound is given as 12.5 mg, and we already calculated the mass of carbon (X) and hydrogen (Y).
- Therefore, the mass of nitrogen (N) in the compound is: 12.5 mg - X - Y = Z.

3. Determine the molar masses of carbon (C), hydrogen (H), and nitrogen (N) by converting the masses calculated in steps 1 and 2 to moles:
- Moles of C = X / atomic mass of C
- Moles of H = Y / atomic mass of H
- Moles of N = Z / atomic mass of N

4. Divide the moles of each element by the smallest obtained mole value to obtain the simplest ratio:
- Determine the smallest mole value (let's say it is Moles_min).
- Divide each moles value by Moles_min.
- Round the ratios to the nearest whole number (or simplest whole number ratio).

5. Using the whole number ratio obtained, write the empirical formula for the compound:
- Use the ratio obtained in the previous step to write the empirical formula. The ratios will indicate the subscripts of each element.

By following these steps, you should be able to find the empirical formula for the compound based on the given data.