Calcium can also be precipitated out of the solution by adding sodium phosphate (Na3PO4) to form solid calcium phosphate.
A.) write a net ionic equation for this process
B.)calculate the mass of this precipitate you would generate from treating 1.000 L of your unknown sample with an excess of sodium phosphate.
Is this unknown sample Ca^2+. Then
3Ca^2+ + 2PO4^3- --> Ca3(PO4)2(s)
You must know mols Ca^2+ from your unknown.
Then mols Ca^2+ x (2 mols PO4^3-/3 mols Ca^2+) = mols Ca^2+ x 2/3 = ? mols Ca3(PO4)2.
Then g = mols x molar mass.
@DrBob222: what about the sodium phosphate?
Sorry about that. I got carried away with calculating the mass Ca3(PO4)2.
mols
? mols Ca^2+ x (2 mol Na3PO4/3 mol Ca^2+) = ? mols Ca^2+ x 2/3 = ? mols Na3PO4. Does that look familar from above.
g Na3PO4 = mols Na3PO4 x molar mass Na3PO4. And that should look familiar from above, also.
A.) To write a net ionic equation, we need to first identify the ions present in the reaction. Sodium phosphate (Na3PO4) dissociates into the sodium ion (Na+) and the phosphate ion (PO4^3-). Calcium phosphate (Ca3(PO4)2) also dissociates into calcium ions (Ca^2+) and phosphate ions (PO4^3-). The ionic equation for the process can be written as:
3Ca^2+ + 2PO4^3- → Ca3(PO4)2 (s)
This equation represents the precipitation of calcium phosphate from the solution.
B.) To calculate the mass of the precipitate generated, we need to know the molar mass of calcium phosphate. The molar mass of Ca3(PO4)2 can be calculated by summing the molar masses of its constituent elements:
Ca: 3 × atomic mass of Ca
P: 1 × atomic mass of P
O: 8 × atomic mass of O
Next, we need to convert the volume of the unknown sample to the number of moles of calcium phosphate using its molar concentration. Assuming we have the molar concentration of the unknown sample, we can use the equation:
moles = concentration × volume
Once we know the moles of calcium phosphate, we can calculate its mass by multiplying the moles by the molar mass. The equation is:
mass = moles × molar mass
Please provide additional information, such as the molar concentration of the unknown sample and the molar mass of calcium phosphate, to calculate the mass of the precipitate generated.