15g of an unknown hydrocarbon burns in oxygen to give 4,7g of carbon dioxide and 19,35g of water calculate the empirical formula
Well, let's start with the carbon dioxide. We know that carbon dioxide contains one carbon atom and two oxygen atoms. So, if we have 4.7 grams of carbon dioxide, we can calculate the number of moles of carbon.
Molar mass of CO2 = 12g + (2 x 16g) = 44g/mol
Moles of carbon = mass of carbon dioxide / molar mass of CO2
= 4.7g / 44g/mol = 0.1068 mol
Now, let's move on to the water. Water contains two hydrogen atoms and one oxygen atom. So, if we have 19.35 grams of water, we can calculate the number of moles of hydrogen.
Molar mass of H2O = 2g + 16g = 18g/mol
Moles of hydrogen = mass of water / molar mass of H2O
= 19.35g / 18g/mol = 1.075 mol
Since you mentioned that the unknown hydrocarbon burns in oxygen, we can assume all the carbon in the hydrocarbon ends up as carbon dioxide, and all the hydrogen ends up as water after combustion.
Now, let's compare the ratio of carbon to hydrogen:
Moles of carbon / Moles of hydrogen = 0.1068 mol / 1.075 mol ≈ 0.0994
To find the empirical formula, we need to simplify this ratio to the nearest whole number. So, let's multiply each mole value by a factor that makes the ratio whole:
Moles of carbon = 0.1068 * 10 = 1.068
Moles of hydrogen = 1.075 * 10 = 10.75
Now, the ratio becomes:
Moles of carbon / Moles of hydrogen = 1.068 / 10.75 ≈ 0.0994
Since the ratio is approximately 0.0994, we can round it to the nearest whole number. In this case, we get:
Carbon : Hydrogen ≈ 1 : 11
Therefore, the empirical formula of the unknown hydrocarbon is CH11.
To calculate the empirical formula of the hydrocarbon, we need to determine the ratio of the elements present in the compound.
1. Determine the moles of carbon dioxide:
- The molar mass of carbon dioxide (CO2) = 12.01 g/mol (for carbon) + 2 * 16.00 g/mol (for oxygen) = 44.01 g/mol
- Moles of CO2 = mass of CO2 / molar mass of CO2 = 4.7 g / 44.01 g/mol
2. Determine the moles of water:
- The molar mass of water (H2O) = 2 * 1.01 g/mol (for hydrogen) + 16.00 g/mol (for oxygen) = 18.02 g/mol
- Moles of H2O = mass of H2O / molar mass of H2O = 19.35 g / 18.02 g/mol
3. Determine the moles of carbon:
- Moles of carbon = moles of CO2 * ratio of carbon in CO2 = (moles of CO2) * (1 mol of carbon / 1 mol of CO2) = (moles of CO2) * (1 mol of carbon / 1 mol of CO2) * (2 moles of O / 2 moles of O) = (moles of CO2) * (1 mol of carbon / 1 mol of CO2) * (2 moles of O / 1 mol of CO2) * (16.00 g/mol of O / 1 mol of O) / (12.01 g/mol of C / 1 mol of C) = (moles of CO2) * 32.00 / 44.01
4. Determine the moles of hydrogen:
- Moles of hydrogen = moles of H2O * ratio of hydrogen in H2O = (moles of H2O) * (2 moles of H / 1 mole of H2O) = (moles of H2O) * (2 moles of H / 1 mole of H2O) * (1.01 g/mol of H / 1 mol of H) = (moles of H2O) * 2.02 / 18.02
5. Calculate the ratios of moles:
- Divide the number of moles of carbon by the smallest number of moles among carbon, hydrogen, and oxygen.
- Divide the number of moles of hydrogen by the smallest number of moles.
- Divide the number of moles of oxygen by the smallest number of moles.
6. Determine the empirical formula:
- Write the empirical formula using the smallest whole-number ratios from step 5.
Let's calculate the empirical formula using these steps:
1. Moles of CO2 = 4.7 g / 44.01 g/mol = 0.1067 mol
2. Moles of H2O = 19.35 g / 18.02 g/mol = 1.073 mol
3. Moles of carbon = (0.1067 mol) * (32.00 / 44.01) = 0.0775 mol
4. Moles of hydrogen = (1.073 mol) * (2.02 / 18.02) = 0.120 mol
5. Ratios of moles:
- Carbon: Hydrogen: Oxygen = 0.0775 mol : 0.120 mol : 0.0534 mol (rounded)
6. Empirical formula: C0.0775H0.120O0.0534 (rounded)
- Multiply the subscripts by a common factor to get whole numbers if necessary. In this case, we can multiply them by 10:
- C0.775H1.20O0.534 (rounded)
- Empirical formula: C8H12O5
Therefore, the empirical formula of the hydrocarbon is C8H12O5.
To find the empirical formula of the hydrocarbon, we need to determine the ratios of the elements present in the compound. In this case, we are given the masses of carbon dioxide and water produced during the combustion of the hydrocarbon.
1. Calculate the moles of carbon dioxide:
We know that the molar mass of carbon dioxide (CO2) is 44 g/mol (12 g/mol for carbon + 2 x 16 g/mol for oxygen).
So, the number of moles of carbon dioxide produced is:
4.7 g / 44 g/mol = 0.107 moles of CO2
2. Calculate the moles of water:
The molar mass of water (H2O) is 18 g/mol (2 x 1 g/mol for hydrogen + 16 g/mol for oxygen).
So, the number of moles of water produced is:
19.35 g / 18 g/mol = 1.075 moles of H2O
3. Determine the number of moles of carbon:
In the combustion reaction of the hydrocarbon, each mole of carbon dioxide produced corresponds to one mole of carbon in the hydrocarbon. So, the number of moles of carbon in the hydrocarbon is also 0.107 moles.
4. Determine the number of moles of hydrogen:
Each mole of water produced consists of two moles of hydrogen. So, the number of moles of hydrogen in the hydrocarbon is 2.075 moles.
5. Calculate the molar ratio of carbon to hydrogen:
To find the simplest possible ratio, divide the number of moles of both elements by the smallest number of moles.
Moles of carbon = 0.107 moles
Moles of hydrogen = 2.075 moles
Divide both by 0.107 (the smallest number of moles):
0.107 moles / 0.107 moles = 1 mole (carbon)
2.075 moles / 0.107 moles ≈ 19.35 moles (hydrogen)
The ratio of carbon to hydrogen in the empirical formula is approximately 1:19.
6. Write the empirical formula:
The empirical formula is written as the simplest ratio of elements, so the empirical formula for the hydrocarbon is CH19.
Therefore, the empirical formula for the unknown hydrocarbon is CH19.