Express the composition of each of the following compounds as the mass percents of its elements...?
59) Express the composition of each of the following compounds as the mass percents of its elements.
a) formaldehyde, CH2O
b) glucose, C6H12O6
c) acetic acid, HC2H3O2
Example: b) glucose.
a. determine the molecular mass of the compound: 6*12+12*1+6*16= 180
Percent of C= 6*12/180 x 100
percent of H= 12*1/180 x 100
percent of O= 6*16/180 x 100
and of course, the percents should add to 100.
Acetic acid, HC2 H3 O2
a) To determine the mass percent composition of formaldehyde (CH2O), we need to calculate the mass of each element relative to the total mass of the compound.
The molar mass of CH2O can be calculated by summing the molar masses of carbon (C), hydrogen (H), and oxygen (O):
- Carbon (C): 1 atom * 12.01 g/mol = 12.01 g/mol
- Hydrogen (H): 2 atoms * 1.01 g/mol = 2.02 g/mol
- Oxygen (O): 1 atom * 16.00 g/mol = 16.00 g/mol
Total molar mass of CH2O = 12.01 + 2.02 + 16.00 = 30.03 g/mol
To calculate the mass percent of each element, we divide the mass contribution of each element by the total molar mass and multiply by 100:
- Carbon: (12.01 g/mol / 30.03 g/mol) * 100 = 40.01%
- Hydrogen: (2.02 g/mol / 30.03 g/mol) * 100 = 6.73%
- Oxygen: (16.00 g/mol / 30.03 g/mol) * 100 = 53.26%
Therefore, the mass percent composition of formaldehyde (CH2O) is approximately:
- Carbon: 40.01%
- Hydrogen: 6.73%
- Oxygen: 53.26%
b) To determine the mass percent composition of glucose (C6H12O6), we need to calculate the mass of each element relative to the total mass of the compound.
The molar mass of C6H12O6 can be calculated by summing the molar masses of carbon (C), hydrogen (H), and oxygen (O):
- Carbon (C): 6 atoms * 12.01 g/mol = 72.06 g/mol
- Hydrogen (H): 12 atoms * 1.01 g/mol = 12.12 g/mol
- Oxygen (O): 6 atoms * 16.00 g/mol = 96.00 g/mol
Total molar mass of C6H12O6 = 72.06 + 12.12 + 96.00 = 180.18 g/mol
To calculate the mass percent of each element, we divide the mass contribution of each element by the total molar mass and multiply by 100:
- Carbon: (72.06 g/mol / 180.18 g/mol) * 100 = 40.01%
- Hydrogen: (12.12 g/mol / 180.18 g/mol) * 100 = 6.73%
- Oxygen: (96.00 g/mol / 180.18 g/mol) * 100 = 53.26%
Therefore, the mass percent composition of glucose (C6H12O6) is approximately:
- Carbon: 40.01%
- Hydrogen: 6.73%
- Oxygen: 53.26%
c) To determine the mass percent composition of acetic acid (HC2H3O2), we need to calculate the mass of each element relative to the total mass of the compound.
The molar mass of HC2H3O2 can be calculated by summing the molar masses of hydrogen (H), carbon (C), and oxygen (O):
- Hydrogen (H): 2 atoms * 1.01 g/mol = 2.02 g/mol
- Carbon (C): 2 atoms * 12.01 g/mol = 24.02 g/mol
- Oxygen (O): 2 atoms * 16.00 g/mol = 32.00 g/mol
Total molar mass of HC2H3O2 = 2.02 + 24.02 + 32.00 = 58.04 g/mol
To calculate the mass percent of each element, we divide the mass contribution of each element by the total molar mass and multiply by 100:
- Hydrogen: (2.02 g/mol / 58.04 g/mol) * 100 = 3.48%
- Carbon: (24.02 g/mol / 58.04 g/mol) * 100 = 41.36%
- Oxygen: (32.00 g/mol / 58.04 g/mol) * 100 = 55.16%
Therefore, the mass percent composition of acetic acid (HC2H3O2) is approximately:
- Hydrogen: 3.48%
- Carbon: 41.36%
- Oxygen: 55.16%
To express the composition of a compound as the mass percent of its elements, you need to calculate the mass percent of each element present in the compound. Here's how you can do it for each of the given compounds:
A) Formaldehyde, CH2O:
1. Find the molar mass of each element in the compound.
- Carbon (C): 12.01 g/mol
- Hydrogen (H): 1.01 g/mol
- Oxygen (O): 16.00 g/mol
2. Calculate the molar mass of the compound.
- Molar mass of CH2O = (12.01 g/mol * 1) + (1.01 g/mol * 2) + (16.00 g/mol * 1) = 30.03 g/mol
3. Calculate the mass percent of each element.
- %C = (mass of C in CH2O / molar mass of CH2O) * 100
- %H = (mass of H in CH2O / molar mass of CH2O) * 100
- %O = (mass of O in CH2O / molar mass of CH2O) * 100
B) Glucose, C6H12O6:
1. Find the molar mass of each element in the compound.
- Carbon (C): 12.01 g/mol
- Hydrogen (H): 1.01 g/mol
- Oxygen (O): 16.00 g/mol
2. Calculate the molar mass of the compound.
- Molar mass of C6H12O6 = (12.01 g/mol * 6) + (1.01 g/mol * 12) + (16.00 g/mol * 6) = 180.18 g/mol
3. Calculate the mass percent of each element.
- %C = (mass of C in C6H12O6 / molar mass of C6H12O6) * 100
- %H = (mass of H in C6H12O6 / molar mass of C6H12O6) * 100
- %O = (mass of O in C6H12O6 / molar mass of C6H12O6) * 100
C) Acetic acid, HC2H3O2:
1. Find the molar mass of each element in the compound.
- Carbon (C): 12.01 g/mol
- Hydrogen (H): 1.01 g/mol
- Oxygen (O): 16.00 g/mol
2. Calculate the molar mass of the compound.
- Molar mass of HC2H3O2 = (1.01 g/mol * 1) + (12.01 g/mol * 2) + (1.01 g/mol * 3) + (16.00 g/mol * 2) = 60.05 g/mol
3. Calculate the mass percent of each element.
- %H = (mass of H in HC2H3O2 / molar mass of HC2H3O2) * 100
- %C = (mass of C in HC2H3O2 / molar mass of HC2H3O2) * 100
- %O = (mass of O in HC2H3O2 / molar mass of HC2H3O2) * 100
By substituting the values and calculating the percentages, you will get the mass percent composition of each element in the given compounds.