a hydrocarbon is burnt completely in excess oxygen. it is found that 1.00g of the hydrocarbon gives 2.93g carbon dioxide and 1.80g water. find the empirical formula of the hydrocarbon (H=1,C=12,O=16)
break up the carbon dioxide to C and O
2.93g>>(12/44)*2.95=.80gC;
break up the water into H and O
1.80g>>1.8*(2/18)=.2gH;
now total them up, change to moles
C=,8g=.8/12=.066moles
H=.2g=.2/1= .2 moles
Notice that the sum of H and C=1.0g, so all O was atmospheric
now divide by the least of the above (.066)
C=1
H=.2/.066=3
empirical: CH3
Well, it seems we have a little fire and water extravaganza here! Let's analyze the situation.
First, we need to find the number of moles of carbon dioxide and water produced. To do that, let's use the molar mass of carbon dioxide (CO2), which is 12 for carbon and 16x2 for oxygen, giving us a total of 44 grams per mole. Dividing the given mass of 2.93g by the molar mass, we find that we have approximately 0.0665 moles of carbon dioxide.
Similarly, using the molar mass of water (H2O), which is 2x1 for hydrogen and 16 for oxygen, giving us a total of 18 grams per mole. Dividing the given mass of 1.80g by the molar mass, we find that we have approximately 0.1 moles of water.
Now, let's identify the number of moles of carbon and hydrogen in the hydrocarbon. From the 1.00g of the hydrocarbon, we have 0.0665 moles of carbon (since 1 mole of carbon dioxide contains 1 mole of carbon) and 0.2 moles of hydrogen (since 1 mole of water contains 2 moles of hydrogen).
Now, to find the ratio of carbon to hydrogen atoms, we need to divide the number of moles. We get the ratio of C to H (approximately) as 0.0665/0.2 = 0.3325/1. Let's simplify it further to C0.3325H1.
Now, we need to convert the ratio to the simplest whole numbers. By multiplying them by 3, we get C1H3, which means we have 1 carbon atom and 3 hydrogen atoms.
Thus, the empirical formula of the hydrocarbon is CH3. Voila!
To find the empirical formula of the hydrocarbon, we need to determine the ratio of carbon to hydrogen in the compound.
Step 1: Find the moles of carbon dioxide (CO2):
Moles of CO2 = mass of CO2 / molar mass of CO2.
Moles of CO2 = 2.93 g / 44.01 g/mol (molar mass of CO2).
Moles of CO2 ≈ 0.0665 mol.
Step 2: Find the moles of water (H2O):
Moles of H2O = mass of H2O / molar mass of H2O.
Moles of H2O = 1.80 g / 18.02 g/mol (molar mass of H2O).
Moles of H2O ≈ 0.0999 mol.
Step 3: Calculate the moles of carbon in the hydrocarbon:
Since one CO2 molecule contains one carbon atom, the moles of carbon will be the same as the moles of CO2.
Moles of carbon ≈ 0.0665 mol.
Step 4: Calculate the moles of hydrogen in the hydrocarbon:
Since one H2O molecule contains two hydrogen atoms, the moles of hydrogen in the hydrocarbon will be twice the moles of H2O.
Moles of hydrogen = 2 × (0.0999 mol).
Moles of hydrogen ≈ 0.1998 mol.
Step 5: Find the mole ratio of carbon to hydrogen:
Divide the moles of carbon and hydrogen by the smallest mole value to simplify the ratio:
Moles of carbon = 0.0665 mol / 0.0665 mol ≈ 1 mol.
Moles of hydrogen = 0.1998 mol / 0.0665 mol ≈ 3 mol.
Step 6: Determine the empirical formula:
The empirical formula shows the simplest whole-number ratio between the atoms in a compound. Since the mole ratio is 1 mole of carbon to 3 moles of hydrogen, the empirical formula of the hydrocarbon is CH3.
Therefore, the empirical formula of the hydrocarbon is CH3.
To find the empirical formula of the hydrocarbon, we need to determine the ratio of carbon, hydrogen, and oxygen atoms in the compound.
Let's start by calculating the number of moles of carbon dioxide (CO2) and water (H2O) formed from 1.00g of the hydrocarbon.
Number of moles of CO2 = Mass of CO2 / Molar mass of CO2
= 2.93g / (12g/mol + 2 * 16g/mol) [since CO2 has one carbon and two oxygen atoms]
= 0.112 mol
Number of moles of H2O = Mass of H2O / Molar mass of H2O
= 1.80g / (2 * 1g/mol + 16g/mol) [since H2O has two hydrogen and one oxygen atoms]
= 0.100 mol
Next, we need to determine the number of moles of carbon and hydrogen in the hydrocarbon.
The carbon and oxygen in CO2 came from the hydrocarbon, so the number of moles of carbon in the hydrocarbon is equal to the number of moles of CO2:
Number of moles of carbon in the hydrocarbon = 0.112 mol
The hydrogen and oxygen in H2O came from the hydrocarbon, so the number of moles of hydrogen in the hydrocarbon is equal to the number of moles of H2O:
Number of moles of hydrogen in the hydrocarbon = 0.100 mol
Now, to find the empirical formula, we need to divide the number of moles of each element by the smallest number of moles obtained. In this case, the smallest number of moles is 0.100 mol.
Moles of carbon in the empirical formula = 0.112 mol / 0.100 mol = 1.12
Moles of hydrogen in the empirical formula = 0.100 mol / 0.100 mol = 1
So, the empirical formula of the hydrocarbon is CH2.
Therefore, the empirical formula of the hydrocarbon is CH2.