Look at sample problem 19.10 in the 8th ed Silberberg book. Write the Ksp expression. Find the concentrations of the ions you need (in this case Ca2 and F-). Put those concentrations into the Ksp expression to calculate Q. Compare Q to K A common laboratory method for preparing a precipitate is to mix solutions containing the component ions. Does a precipitate form when 10. ml of 0.0010 M Ca(NO3)2 is mixed with 10. ml of 0.00010 M NaF

Respuesta :

Answer:

Explanation:

From the information given:

[tex]CaF_2 \to Ca^{2+} + 2F^-[/tex]

[tex]Ksp = 3.2 \times 10^{-11}[/tex]

no of moles of [tex]Ca^{2+}[/tex] = 0.01 L × 0.0010 mol/L

no of moles of [tex]Ca^{2+}[/tex] = [tex]1 \times 10^{-5} \ mol[/tex]

no of moles of [tex]F^-[/tex] = 0.01 L × 0.00010 mol/L

no of moles of [tex]F^-[/tex] = [tex]1 \times 10^{-6}\ mol[/tex]

Total volume = 0.02 L

[tex][Ca^{2+}}] = \dfrac{1\times10^{-5} \ mol}{0.02 \ L} \\ \\ \\ \[[Ca^{2+}}] = 0.0005 \ mol/L[/tex]

[tex][F^{-}] = \dfrac{(1\times 10^{-6} \ mol)}{0.02 \ L}[/tex]

[tex][F^{-}] = 5 \times 10^{-5} \ mol/L[/tex]

[tex]Q = [Ca^{2+}][F^-]^2 \\ \\ Q = 0.0005 \times (5\times 10^{-5})^2 \\ \\ Q = 1.25 \times 10^{-12}[/tex]

Since Q<ksp, then there will no be any precipitation of CaF2