How many oxygen atoms do you have in 2.00 grams of calcium phosphate?
Do you use avogadro's number and how?
How many Ca^2+ ions do you have in 2.00 grams of calcium phosphate?
Any help would be greatly appreciated.
The formula for calcium phoshpate is
Ca3(PO4)2. First calculate the molar mass of that molecule. It is about 3x40 + 2x31 + 8x16 = 310 g/mol. You can get a more accurate value using more significant figures for ate atomic weights.
2 grams of the compound is only 2/31 mole. Multiply that by Avogadro's number for the number of molecules. There are 3 Ca2+ ions per molecule and 8 O atoms per molecule.
To determine the number of oxygen atoms in 2.00 grams of calcium phosphate and the number of Ca^2+ ions, we'll need to use Avogadro's number and the molar mass of calcium phosphate.
1. Calculate the molar mass of calcium phosphate (Ca3(PO4)2):
- The molar mass of calcium (Ca) is approximately 40.08 g/mol.
- The molar mass of phosphorus (P) is approximately 30.97 g/mol.
- The molar mass of oxygen (O) is approximately 16.00 g/mol.
- Calcium phosphate (Ca3(PO4)2) consists of 3 calcium ions, 2 phosphate ions, and 8 oxygen atoms.
- Therefore, the molar mass of calcium phosphate is:
(3 * 40.08 g/mol) + (2 * (30.97 g/mol + 4 * 16.00 g/mol))
= 120.24 g/mol + 2 * (30.97 g/mol + 64.00 g/mol)
= 120.24 g/mol + 2 * 94.97 g/mol
= 120.24 g/mol + 189.94 g/mol
= 310.18 g/mol
2. Determine the number of moles of calcium phosphate:
- To do this, divide the mass (in grams) by the molar mass:
2.00 g / 310.18 g/mol = 0.00645 mol
3. Calculate the number of oxygen atoms:
- Since each molecule of calcium phosphate (Ca3(PO4)2) contains 8 oxygen atoms, we can multiply the number of moles calculated in step 2 by Avogadro's number:
0.00645 mol * 6.022 × 10^23 molecules/mol * 8 atoms/molecule = 309.94 × 10^19 oxygen atoms
Therefore, there are approximately 309.94 × 10^19 oxygen atoms in 2.00 grams of calcium phosphate.
4. Determine the number of Ca^2+ ions:
- Since each molecule of calcium phosphate (Ca3(PO4)2) contains 3 calcium ions, we can multiply the number of moles calculated in step 2 by Avogadro's number:
0.00645 mol * 6.022 × 10^23 ions/mol * 3 ions/molecule = 116.18 × 10^23 Ca^2+ ions
Therefore, there are approximately 116.18 × 10^23 Ca^2+ ions in 2.00 grams of calcium phosphate.
To find the number of oxygen atoms in 2.00 grams of calcium phosphate, we need to use Avogadro's number.
Avogadro's number is a constant that represents the number of atoms, ions, or molecules in one mole of a substance, and it is approximately 6.022 x 10^23 particles per mole.
To start, we need to determine the molar mass of calcium phosphate (Ca3(PO4)2) by adding up the atomic masses of its constituent elements: calcium (Ca), phosphorus (P), and oxygen (O).
The atomic masses are as follows:
- Calcium (Ca) = 40.08 g/mol
- Phosphorus (P) = 30.97 g/mol
- Oxygen (O) = 16.00 g/mol
To calculate the molar mass of calcium phosphate, multiply the atomic masses by the number of atoms present in the compound:
- Calcium mass: 40.08 g/mol x 3 (three calcium atoms) = 120.24 g/mol
- Phosphorus mass: 30.97 g/mol x 1 (one phosphorus atom) = 30.97 g/mol
- Oxygen mass: 16.00 g/mol x 8 (eight oxygen atoms) = 128.00 g/mol
Add up the individual masses to get the molar mass of calcium phosphate:
120.24 g/mol + 30.97 g/mol + 128.00 g/mol = 279.21 g/mol
Now, use Avogadro's number to convert the mass of the compound (2.00 grams) to the number of moles and then to the number of oxygen atoms.
First, calculate the number of moles of calcium phosphate using the formula:
moles = mass (in grams) / molar mass
moles = 2.00 g / 279.21 g/mol ≈ 0.00715 moles
Next, since the molar ratio of oxygen atoms to calcium phosphate is 8:1 (as there are 8 oxygen atoms per calcium phosphate molecule), multiply the number of moles by Avogadro's number to obtain the number of oxygen atoms:
number of oxygen atoms = moles × Avogadro's number
number of oxygen atoms = 0.00715 moles × (6.022 × 10^23 particles/mol) ≈ 4.31 × 10^21 oxygen atoms
Therefore, in 2.00 grams of calcium phosphate, there are approximately 4.31 × 10^21 oxygen atoms.
Now, to find the number of Ca^2+ ions in 2.00 grams of calcium phosphate, we need to consider the stoichiometry of the compound.
In calcium phosphate, there are two calcium ions (Ca^2+) per molecule. Therefore, the number of moles of calcium ions is the same as the number of moles of calcium phosphate, which is approximately 0.00715 moles.
To find the number of Ca^2+ ions, multiply the moles by Avogadro's number:
number of Ca^2+ ions = moles × Avogadro's number
number of Ca^2+ ions = 0.00715 moles × (6.022 × 10^23 particles/mol) ≈ 4.31 × 10^21 Ca^2+ ions
Therefore, there are approximately 4.31 × 10^21 Ca^2+ ions in 2.00 grams of calcium phosphate.
I hope this explanation helps! Let me know if you have any further questions.