Question

Am I doing this right?
Find the concentration of the phosphate ion. 1.00 mL 210 micro molar. DI water added to 25 ml line.
1.00 mL phosphate solution * 1L/1000mL * 210 mol phosphate solution/1L solution * 1.0 *10^-6 mol/ 1 micromol * 1 mol PO4 3- / 1 mol solution = 2.1*10^-7
Then divide by .025 L = 8.40 * 10^-6

Answer 1

you diluted a 210 μM solution to 1/25 of its original

210 / 25 = 8.4

looks good

Answer 2

210e-6 molar of what? Phosophate ion?

seems to me if it 210e^-6 M, and you dilute it 25 times , then it is diluted 25 times.
or new concentration is 210e-6/25=8.40 * 10^-6 M

Answer 3

Thanks!