What is the percentage of mass of A. Phosphorus in Ca3(PO4)2 B. Nitrogen in (NH4)3PO4?
Phosphorus in Ca3(PO4)2
Let's do this by common sense. If I gave you a basket containing 5 pounds of apples and 5 pounds of oranges and asked you to calculate percent apples and oranges I know you would say, "That's easy. It's 50% each, of course." And of course you would be right. BUT, how did you calculate that?
You said I have 5 pou
nds apples in a total of 10 pounds for both so (5 pounds apples/10 total) *100 = 50%. Chemicals don't make it any different so treat it the same way. For part A, it is (mass P/total mass)*100 = % P
[(2*atomic mass P)/(total mass Ca3(PO4)2]*100 = ?
Part B is worked the same way.
To find the percentage of mass of an element in a compound, you need to know the molar masses of the elements involved and the molecular formula of the compound.
Let's calculate the percentage of mass of phosphorus in Ca3(PO4)2 and nitrogen in (NH4)3PO4.
A. Phosphorus in Ca3(PO4)2:
1. Determine the molar mass of phosphorus (P) from the periodic table, which is approximately 31.0 grams/mol.
2. Calculate the molar mass of Ca3(PO4)2 by adding up the molar masses of each element in the compound:
- Calcium (Ca) has a molar mass of approximately 40.1 grams/mol.
- Oxygen (O) has a molar mass of approximately 16.0 grams/mol.
Since there are three calcium atoms and two phosphate groups (PO4) in the compound, the calculation would be:
Molar mass of Ca3(PO4)2 = (3 * molar mass of Ca) + (2 * molar mass of PO4)
Molar mass of Ca3(PO4)2 = (3 * 40.1) + (2 * (31.0 + (4 * 16.0)))
Molar mass of Ca3(PO4)2 = 120.3 + 284.0
Molar mass of Ca3(PO4)2 = 404.3 grams/mol
3. To find the percentage of mass of phosphorus (P) in the compound, use the formula:
Percentage of mass = (molar mass of P / molar mass of compound) * 100
Percentage of mass = (31.0 / 404.3) * 100
B. Nitrogen in (NH4)3PO4:
1. Determine the molar mass of nitrogen (N) from the periodic table, which is approximately 14.0 grams/mol.
2. Calculate the molar mass of (NH4)3PO4 by adding up the molar masses of each element in the compound:
- Hydrogen (H) has a molar mass of approximately 1.0 grams/mol.
Since there are three ammonium groups (NH4) in the compound, the calculation would be:
Molar mass of (NH4)3PO4 = (3 * molar mass of NH4) + molar mass of PO4
Molar mass of (NH4)3PO4 = (3 * (1.0 + (4 * 1.0))) + (14.0 + (4 * 16.0))
Molar mass of (NH4)3PO4 = 3.0 + 60.0
Molar mass of (NH4)3PO4 = 63.0 grams/mol
3. To find the percentage of mass of nitrogen (N) in the compound, use the formula:
Percentage of mass = (molar mass of N / molar mass of compound) * 100
Percentage of mass = (14.0 / 63.0) * 100
By following these steps, you can calculate the percentage of mass of phosphorus in Ca3(PO4)2 and nitrogen in (NH4)3PO4.