A 25g sample of a compound composed of Carbon, Hydrogen, and Oxygen was combusted. 55grams of Carbon Dioxide and 30 grams of water were collected.

A) What is the empirical formula of the compound?
B) If the compound has a molar mass of 120g what is the molecular formula?

Convert 55 g CO2 to grams C.

Convert 30 g H2O to grams H.
Calculate grams oxygen = 25- g C - g H.

Convert grams to moles.
moles C = g C/atomic mass C.
moles H = g H/atomic mass H.
moles O = g O/atomic mass O.

Now you want to determine the ratio of these elements to each other with the smallest number being 1.00. The easy way to do that is to divide the smallest number by itself (thereby assuring yourself that will be 1.0000), then divide the other two numbers by the same small number. Round to whole numbers. Post your work if you get stuck.

A 25g sample of a compound composed of Carbon, Hydrogen, and Oxygen was combusted. 55grams of Carbon Dioxide and 30 grams of water were collected.

A) What is the empirical formula of the compound?
B) If the compound has a molar mass of 120g what is the molecular formula

To find the empirical formula of a compound, you need to determine the ratio of the elements present.

A) To find the empirical formula, you should start by calculating the number of moles of carbon, hydrogen, and oxygen in the compound.

1. Calculate the number of moles of carbon dioxide (CO2) using its molar mass of 44 g/mol. Divide the mass of the carbon dioxide collected (55 g) by its molar mass (44 g/mol) to get the number of moles. In this case, you will have 55 g / 44 g/mol = 1.25 mol of carbon dioxide.

2. Since each molecule of carbon dioxide contains one carbon atom, there will be 1.25 mol of carbon atoms present.

3. Calculate the number of moles of water (H2O) using its molar mass of 18 g/mol. Divide the mass of water collected (30 g) by its molar mass (18 g/mol) to find the number of moles. In this case, you will have 30 g / 18 g/mol = 1.67 mol of water.

4. Each water molecule contains two hydrogen atoms, so there will be 1.67 mol of water x 2 mol H/mol H2O = 3.34 mol of hydrogen atoms present.

5. To find the number of moles of oxygen, use the difference in moles between the total moles of carbon dioxide and water. Subtract the moles of carbon dioxide (1.25 mol) and hydrogen (3.34 mol) from the total moles of the compound (25g). In this case, there will be 25 g - 1.25 mol - 3.34 mol = 20.41 g/mol of oxygen.

6. Convert the remaining mass of oxygen (20.41 g) to moles by dividing it by the molar mass of oxygen (16 g/mol). In this case, you will have 20.41 g / 16 g/mol = 1.28 mol of oxygen.

Now, to determine the empirical formula, divide the number of moles of each element by the smallest number of moles present. In this case, the smallest number of moles is 1.25 (from carbon).

Carbon: 1.25 mol / 1.25 mol = 1
Hydrogen: 3.34 mol / 1.25 mol = 2.67 (rounded to 3)
Oxygen: 1.28 mol / 1.25 mol = 1.02 (rounded to 1)

Therefore, the empirical formula of the compound is CH3O.

B) To find the molecular formula, you need to know the molar mass of the empirical formula. In this case, the molar mass of the empirical formula CH3O is:

(12 g/mol x 1) + (1 g/mol x 3) + (16 g/mol x 1) = 32 g/mol

Divide the given molecular mass (120 g/mol) by the molar mass of the empirical formula (32 g/mol) to find the ratio between the two.

120 g/mol / 32 g/mol = 3.75

Since the ratio is approximately 3.75, you can round it to the nearest whole number to get the multiplier for the empirical formula.

So, the molecular formula will be (CH3O) multiplied by 4:

(CH3O) x 4 = C4H12O4

Therefore, the molecular formula of the compound is C4H12O4.