When a 0.952 g sample of an organic compound containing C, H,and O is burned completely in oxygen, 1.35 g of CO2 and0.826 g of H2O are produced. What is the empiricalformula of the compound?
Convert 1.35g CO2 to g C.
Convert 0.826 H2O to g H
Add gC+gH and subtract from 0.952 to obtain g O.
Now convert g each to moles. moles = grams/molar mass
Find the ratio of each element to one another with the lowest number being 1.00. The easy way to do that is to divide the smallest number by itself, then divide the other numbers by the same small number.
Post your work if you run into trouble.
C in CO2 is 12/ 44 % = 27.27%
in 1.35 g of CO2 there is (27.27% of 1.35) g of C = 0.3681g or 0.3681 /12 moles of C = 0.031 moles
% C in the compound = .3681 / .952 = 38.67%
H in H2O = 2 / 18 % = 11.111 %
in .826 g of H2O we have 11.11 % of .826 = 0.09177 g of H or 0.09177 / 1 moles of H = 0.09177 moles
% H in the compound = .09177 / .952 = 9.64%
% of O in the compound = 100 - ( 38.67 + 9.64) % = 51.69 %
mass of O = 51.69 % of .925 = 0.4781 g of O or 0.0.4781 / 16 moles of O = 0.02988 moles
ratio of moles of C:H:O = 0.031: 0.09177: 0.02988
divide by the smallest number and we get 1.03 : 3.07: 1
or 1:3:1
empirical formula is CH3O ..
Well, it seems like we have a melting pot of elements here! Let's break it down, shall we?
First, let's find the number of moles of carbon dioxide (CO2) produced. The molar mass of CO2 is 44 g/mol, so the number of moles of CO2 can be calculated using the equation:
moles of CO2 = mass of CO2 / molar mass of CO2
moles of CO2 = 1.35 g / (44 g/mol) = 0.0307 mol
Next, let's find the number of moles of water (H2O) produced. The molar mass of H2O is 18 g/mol, so the number of moles of H2O can be calculated using the equation:
moles of H2O = mass of H2O / molar mass of H2O
moles of H2O = 0.826 g / (18 g/mol) = 0.0459 mol
Now, let's determine the number of moles of carbon (C) in the sample. Since each mole of CO2 contains 1 mole of carbon, the number of moles of carbon is equal to the number of moles of CO2:
moles of C = 0.0307 mol
Similarly, let's determine the number of moles of hydrogen (H) in the sample. Since each mole of H2O contains 2 moles of hydrogen, the number of moles of hydrogen is twice the number of moles of H2O:
moles of H = 2 * 0.0459 mol = 0.0918 mol
Finally, let's calculate the number of moles of oxygen (O) in the sample. We can do this by subtracting the combined number of moles of carbon and hydrogen from the total number of moles in the sample:
moles of O = total moles - moles of C - moles of H
moles of O = 0.952 g / (molar mass of the compound)
The molar mass of the compound can be calculated using the equation:
molar mass = mass of compound / moles of compound
molar mass = 0.952 g / (0.0307 mol + 0.0918 mol)
After calculating the molar mass, we can substitute it back into the moles of oxygen equation to find the number of moles of oxygen.
Once we have the number of moles for each element, we can divide them by the smallest number of moles to obtain a simple, whole-number ratio. This ratio corresponds to the empirical formula of the compound.
So, tell me, are you ready to embark on this mole-y adventure?
To determine the empirical formula of the compound, we need to find the ratios of the elements present. We can do this by finding the moles of carbon, hydrogen, and oxygen in the given amounts of CO2 and H2O.
1. Find the moles of CO2:
- Given mass of CO2 = 1.35 g
- Molar mass of CO2 = 44 g/mol (12 g/mol for carbon + 16 g/mol for oxygen)
- Moles of CO2 = mass of CO2 / molar mass of CO2
= 1.35 g / 44 g/mol
≈ 0.0307 mol
2. Find the moles of H2O:
- Given mass of H2O = 0.826 g
- Molar mass of H2O = 18 g/mol (2 g/mol for hydrogen + 16 g/mol for oxygen)
- Moles of H2O = mass of H2O / molar mass of H2O
= 0.826 g / 18 g/mol
≈ 0.0459 mol
3. Calculate the moles of carbon, hydrogen, and oxygen in the compound:
- Moles of carbon = moles of CO2 × (1 mol of carbon / 1 mol of CO2)
≈ 0.0307 mol × (1 mol / 1 mol)
≈ 0.0307 mol
- Moles of hydrogen = moles of H2O × (2 mol of hydrogen / 1 mol of H2O)
≈ 0.0459 mol × (2 mol / 1 mol)
≈ 0.0918 mol
- Moles of oxygen = (moles of carbon in CO2) + (moles of hydrogen in H2O)
≈ (2 × moles of CO2) + (1 × moles of H2O)
≈ (2 × 0.0307 mol) + (1 × 0.0459 mol)
≈ 0.1073 mol
4. Find the mole ratios of carbon, hydrogen, and oxygen:
- Divide the number of moles of each element by the smallest number of moles (carbon, in this case) to obtain the simplest, whole number ratio.
- Carbon: 0.0307 mol / 0.0307 mol ≈ 1
- Hydrogen: 0.0918 mol / 0.0307 mol ≈ 3
- Oxygen: 0.1073 mol / 0.0307 mol ≈ 3.5 (rounded to the nearest whole number)
5. Adjust the mole ratio to obtain whole numbers:
- Multiply the ratio by 2 to eliminate the fraction for oxygen:
- Carbon: 1 × 2 = 2
- Hydrogen: 3 × 2 = 6
- Oxygen: 3.5 × 2 = 7
6. The empirical formula of the compound is C2H6O7.
To determine the empirical formula of the compound, we need to find the ratio of the elements present in the compound. In this case, we are given the masses of carbon dioxide (CO2) and water (H2O) produced from the combustion of the compound.
Step 1: Find the moles of carbon dioxide (CO2):
First, calculate the molar mass of CO2:
C: 12.01 g/mol
O: 16.00 g/mol (2 oxygen atoms per molecule)
Molar mass of CO2 = 12.01 g/mol + (16.00 g/mol × 2) = 44.01 g/mol
Next, find the number of moles of CO2 produced:
moles of CO2 = mass of CO2 / molar mass of CO2 = 1.35 g / 44.01 g/mol
Step 2: Find the moles of water (H2O):
Calculate the molar mass of H2O:
H: 1.01 g/mol (2 hydrogen atoms per molecule)
O: 16.00 g/mol
Molar mass of H2O = 1.01 g/mol × 2 + 16.00 g/mol = 18.02 g/mol
Now, find the number of moles of H2O produced:
moles of H2O = mass of H2O / molar mass of H2O = 0.826 g / 18.02 g/mol
Step 3: Find the moles of carbon, hydrogen, and oxygen:
Since the combustion of the compound produced carbon dioxide (CO2) and water (H2O), the moles of carbon (C) can be obtained from the moles of CO2, and the moles of hydrogen (H) can be obtained from the moles of H2O.
Moles of C = moles of CO2
Moles of H = 2 × moles of H2O (there are two hydrogen atoms per molecule of water)
Moles of O = moles of CO2 + moles of H2O (since CO2 contains two oxygen atoms)
Step 4: Determine the simplest whole number ratio:
Now, divide the moles of carbon, hydrogen, and oxygen by the smallest value among them to obtain the simplest whole number ratio. If necessary, multiply all the ratios by the same number to convert them to whole numbers.
Once you have the simplest whole number ratio, determine the empirical formula by writing the elements with their respective subscripts.
For example, if you find that the ratio is C: 1, H: 2, O: 1, the empirical formula would be CH2O.
By following these steps, you can determine the empirical formula of the given organic compound.