Solve of for The percentage of carbon hydrogen and oxygen in vitamin C were determine by burning a sample weighing 2.00mg the masses Co2 and water found were 3.00mg and 0.81mg respectively,Given that the molar mass of vitamin C is 180g, determine the molecular mass
CxHyOz ==> CO2 + H2O
....2 mg...........3 mg....0.81 mg
mm = molar mass: am = atomic mass and
mass C = mass CO2 x (am C/mm CO2)
mass C = 3 mg x (12/44) = 0.818 mg
mass H = mass H2O x (2*am H/mm H2O)
mass H = 0.81 mg x (2*1/18) = 0.09 mg
mass O = mass CxHyOz -mass H - mass C or
mass O = 2 mg - 0.818 mg - 0.09 mg = 1.092 mg
%C = (mass C/total mass)*100 = (0.818/2)100 = 40.9%
%H = (mass H/total mass)*100 = (0.09/2)100 = 4.50%
%O = 100% - %C - %H = 100 - 40.9 - 4.50 = 54.6%
Next, determine the empirical formula for vitamin C.
Take a 100 g sample which gives
C = 40.9 grams
H = 4.50 grams
O = 54.6 grams.
Convert the grams to mols this way. mols = g/atomic mass
mols C = 40.9/12 = 3.41
mols H = 4.50/1 = 4.50
mols O = 54.6/16 = 3.41
You want to find the ratio of these elements to each other with the smallest being no less than 1 AND you want small whole numbers; i.e., the easiest way is to divide the smallest number by itself and divide the others numbers by the same small number.
mols C = 3.41/3.41 = 1.00
mols H = 4.50/3.41 = 1.32
mols O = 3.41/3.41 = 1.00
These aren't small whole numbers to you multiply everything by whole numbers to see if you can find one with whole numbers. If we try 2 here is what you get:
mols C = 1.00 x 2 = 2.00
mols H = 1.32 x 2 = 2.64
mols O = 1.00 x 2 = 2.00
Nope. That is it because 2.64 is not a small whole number. Try multiplying by 3 to get:
mols C = 1.00 x 3 = 3.00
mols H = 1.32 x 3 = 3.94 which rounds to 4
mols O = 2.00 x 3 = 3.00 so the empirical formula (that CxHyOz) is C3H4O3 so the empirical mass is 3*12 + 4*H + 3*16 = 88
The problem tells you that the molar mass is 180 (which isn't quite correct) but 88 x some whole number = 180 and
some whole number = 180/88 = 2.04 which rounds to 2.00 so the molecular formula is (C3H4O3)2 or C6H8O6. The molar mass is
6*12 + 8*1 + 6*16 = 176.
You're welcome.
Well, let's break this down! If we know the masses of the CO2 and water produced, we can find the masses of carbon and hydrogen in vitamin C.
First, we'll calculate the mass of carbon in the CO2 produced:
Mass of carbon = mass of CO2 = 3.00mg
Now, the molecular weight of CO2 is:
Molecular weight of CO2 = 12.01g/mol (molar mass of carbon) + 2 * 16.00g/mol (molar mass of oxygen) = 44.01g/mol
Using this information, we can calculate the moles of carbon:
Moles of carbon = mass of carbon / molecular weight of CO2
Now, let's move on to calculating the mass of hydrogen in the water produced:
Mass of hydrogen = mass of water = 0.81mg
The molecular weight of water is:
Molecular weight of water = 2 * 1.01g/mol (molar mass of hydrogen) + 16.00g/mol (molar mass of oxygen) = 18.02g/mol
Using this information, we can calculate the moles of hydrogen:
Moles of hydrogen = mass of hydrogen / molecular weight of water
Given that the molecular mass of vitamin C is 180g/mol, we can find the moles of oxygen:
Moles of oxygen = (2.00mg - mass of carbon - mass of hydrogen) / 180g/mol
Now, using the moles of carbon, hydrogen, and oxygen, we can determine the percentage composition of each element:
Percentage of carbon = (moles of carbon / total moles) * 100
Percentage of hydrogen = (moles of hydrogen / total moles) * 100
Percentage of oxygen = (moles of oxygen / total moles) * 100
Remember, though, this is just the scientific side of things. If you need any jokes to lighten the mood, I'm here for that too!
To determine the molecular mass of vitamin C, we need to calculate the combined mass of carbon, hydrogen, and oxygen in the compound.
Step 1: Calculate the mass of carbon (C) in the given sample.
Given: Mass of CO2 = 3.00 mg
The molar mass of CO2 = 44 g/mol (C = 12 g/mol, O = 16 g/mol)
Using the molar mass of CO2, we can calculate the moles of CO2 as follows:
Moles of CO2 = Mass of CO2 / Molar mass of CO2
Moles of CO2 = 3.00 mg / 44 g/mol
Moles of C = Moles of CO2 (since there is 1 carbon atom in 1 CO2 molecule)
Moles of C = 3.00 mg / 44 g/mol
Step 2: Calculate the mass of hydrogen (H) in the given sample.
Given: Mass of water = 0.81 mg
The molar mass of water (H2O) = 18 g/mol (H = 1 g/mol, O = 16 g/mol)
Using the molar mass of water, we can calculate the moles of water as follows:
Moles of water = Mass of water / Molar mass of water
Moles of water = 0.81 mg / 18 g/mol
Moles of H = 2 * Moles of water (since there are 2 hydrogen atoms in 1 H2O molecule)
Moles of H = 2 * (0.81 mg / 18 g/mol)
Step 3: Calculate the mass of oxygen (O) in the given sample.
To find the mass of oxygen, we subtract the masses of carbon and hydrogen from the total mass of the sample.
Mass of O = Total mass of sample - Mass of C - Mass of H
Mass of O = 2.00 mg - Mass of C - Mass of H
Step 4: Calculate the molecular mass of vitamin C.
Given: Molar mass of vitamin C = 180 g/mol
The molecular mass of vitamin C is the sum of the masses of carbon, hydrogen, and oxygen in the compound.
Molecular mass of vitamin C = Mass of C + Mass of H + Mass of O
Now, let's substitute the calculated values into the equation and solve for the molecular mass:
Molecular mass of vitamin C = (Moles of C * Atomic mass of C) + (Moles of H * Atomic mass of H) + (Mass of O * Atomic mass of O)
Finally, substitute the calculated values into the equation and solve:
Molecular mass of vitamin C = (3.00 mg / 44 g/mol * 12 g/mol) + (2 * (0.81 mg / 18 g/mol) * 1 g/mol) + (2.00 mg - Mass of C - Mass of H) * 16 g/mol
After calculating the equation, the final result will give you the molecular mass of vitamin C.
To determine the molecular mass of vitamin C, we need to first calculate the moles of carbon dioxide (CO2) and water (H2O) produced when the sample is burned.
1. Calculate the moles of CO2:
- The mass of CO2 produced is 3.00 mg.
- To convert this to grams, divide by 1000: 3.00 mg ÷ 1000 = 0.00300 g.
- The molar mass of CO2 is 44.01 g/mol (carbon: 12.01 g/mol, oxygen: 16.00 g/mol).
- Use the formula: moles = mass / molar mass.
- Moles of CO2 = 0.00300 g / 44.01 g/mol.
- Calculate the moles and round to the appropriate number of significant figures.
2. Calculate the moles of water:
- The mass of water produced is 0.81 mg.
- To convert this to grams, divide by 1000: 0.81 mg ÷ 1000 = 0.00081 g.
- The molar mass of H2O is 18.02 g/mol (hydrogen: 1.01 g/mol, oxygen: 16.00 g/mol).
- Use the formula: moles = mass / molar mass.
- Moles of H2O = 0.00081 g / 18.02 g/mol.
- Calculate the moles and round to the appropriate number of significant figures.
Now that we have the moles of CO2 and H2O, we can calculate the moles of C, H, and O in the sample.
3. Moles of carbon (C):
- Each molecule of CO2 contains 1 atom of carbon, so the moles of carbon = moles of CO2.
4. Moles of hydrogen (H):
- Each molecule of H2O contains 2 atoms of hydrogen, so the moles of hydrogen = 2 × moles of H2O.
5. Moles of oxygen (O):
- To determine the moles of oxygen, subtract the moles of carbon and hydrogen from the total moles of CO2 and H2O. This is because each molecule of CO2 contains 2 atoms of oxygen, and each molecule of H2O contains 1 atom of oxygen.
- Moles of oxygen = (moles of CO2 × 2) + (moles of H2O × 1).
Finally, to determine the molecular mass of vitamin C:
6. Molecular mass:
- Multiply the moles of each element by its respective molar mass:
- Mass of carbon (C) = moles of carbon × atomic mass of carbon.
- Mass of hydrogen (H) = moles of hydrogen × atomic mass of hydrogen.
- Mass of oxygen (O) = moles of oxygen × atomic mass of oxygen.
- The molecular mass of vitamin C = Mass of carbon + Mass of hydrogen + Mass of oxygen.
Note: The atomic masses used in the calculations are based on the periodic table.