Question

Write the charge and mass balances for dissolving ${\mathbf{CaF}}_{\mathbf{2}}$ in water if the reactions are

role="math" localid="1654770961556" $$\begin{gathered} {\mathbf{CaF}}_{\mathbf{2}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{ٟ}\mathbf{}\mathbf{}\mathbf{}\mathbf{}{\mathbf{Ca}}^{\mathbf{2}\mathbf{+}}\mathbf{+}\mathbf{2}\mathbf{F} \\ {\mathbf{Ca}}^{\mathbf{2}\mathbf{+}}\mathbf{+}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{ٟ}\mathbf{}\mathbf{}\mathbf{}\mathbf{}{\mathbf{CaOH}}^{\mathbf{+}}\mathbf{+}{\mathbf{H}}^{\mathbf{+}} \\ {\mathbf{Ca}}^{\mathbf{2}\mathbf{+}}\mathbf{F}\mathbf{ؚ}\mathbf{}\mathbf{}\mathbf{}\mathbf{}{\mathbf{CaF}}^{\mathbf{+}}{\mathbf{CaF}}_{\mathbf{2}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{ؚ}\mathbf{}\mathbf{}\mathbf{}{\mathbf{CaF}}_{\mathbf{2}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)} \\ \mathbf{F}\mathbf{+}{\mathbf{H}}^{\mathbf{+}}\mathbf{}\mathbf{ؚ}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{HF}\mathbf{\left(}\mathbf{aq}\mathbf{\right)} \\ \mathbf{HF}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{F}\mathbf{}\mathbf{ؚ}\mathbf{}\mathbf{}\mathbf{}{\mathbf{HF}}_{\mathbf{2}} \end{gathered}$$

Short answer

The process's mass balance is determined by ${\mathrm{CaF}}_2$gives $2\mathrm{m}\mathrm{ol}\mathrm{F}$for each molCa.

role="math" localid="1654772123295" $$\begin{gathered} \underset{\mathrm{species}\mathrm{containing}\mathrm{F}}{\underbrace{\left[{\mathrm{F}}^{-}\right]+\left[{\mathrm{CaF}}^{+}\right]+2\left[{\mathrm{CaF}}_{2\left(\mathrm{aq}\right)}\right]+\left[{\mathrm{HF}}^{-}\right]+2\left[{\mathrm{HF}}_2^{-}\right]}} \\ =\underset{\mathrm{species}\mathrm{containing}{\mathrm{Ca}}^{2+}}{\underbrace{2\left\{\left[{\mathrm{Ca}}^{2+}\right]+\left[{\mathrm{CaOH}}^{+}\right]+\left[{\mathrm{CaF}}^{+}\right]+2\left[{\mathrm{CaF}}_{2\left(\mathrm{aq}\right)}\right]\right\}}} \end{gathered}$$

Step-by-step solution

Definition of calcium fluriode CaF2

• Calcium fluoride (CaF2) is an inorganic compound made up of the elements calcium and fluorine.
• It's an insoluble white solid. Fluorite (also known as fluorspar) is the mineral form, which is often richly coloured due to impurities.

Determine the charge and mass balances for dissolving CaF2

The dissolving charge and mass balances${\mathrm{CaF}}_2$It must be given in water.

Balance of charge: [C] -concentration of a cation and n-charge of the cation.

The [A] -concentration of an anion and the m-magnitude of the anion's charge.

The total number of species in a solution containing a certain atom (or group of atoms) must equal the total amount of that atom (or group) given to the solution (mass balance)..

In the given information,

$$\begin{gathered} {\mathrm{CaF}}_2\left(\mathrm{s}\right)\mathrm{ٟ}{\mathrm{Ca}}^{2+}+2\mathrm{F} \\ {\mathrm{Ca}}^{2+}+{\mathrm{H}}_2\mathrm{O}\mathrm{ٟ}{\mathrm{CaOH}}^{+}+{\mathrm{H}}^{+} \\ {\mathrm{Ca}}^{2+}\mathrm{F}\mathrm{ؚ}{\mathrm{CaF}}^{+}{\mathrm{CaF}}_2\left(\mathrm{s}\right)\mathrm{ؚ}{\mathrm{CaF}}_2\left(\mathrm{aq}\right) \\ \mathrm{F}+{\mathrm{H}}^{+}\mathrm{ؚ}\mathrm{HF}\left(\mathrm{aq}\right) \\ \mathrm{HF}\left(\mathrm{aq}\right)+\mathrm{F}\mathrm{ؚ}{\mathrm{HF}}_2 \end{gathered}$$

On the basis of electroneutrality, charge balance:

role="math" localid="1654771916727" $\left[{\mathrm{F}}^{-}\right]+\left[{\mathrm{HF}}_2^{-}\right]+\left[{\mathrm{OH}}^{-}\right]=2\left[{\mathrm{Ca}}^{2+}\right]+\left[{\mathrm{CaOH}}^{+}\right]+\left[{\mathrm{CaF}}^{+}\right]+\left[{\mathrm{H}}^{+}\right]$

By definition, the process's mass balance is determined by ${\mathrm{CaF}}_2$

gives 2 m ol F for each molCa.

$$\begin{gathered} \underset{\mathrm{species}\mathrm{containing}\mathrm{F}}{\underbrace{\left[{\mathrm{F}}^{-}\right]+\left[{\mathrm{CaF}}^{+}\right]+2\left[{\mathrm{CaF}}_{2\left(\mathrm{aq}\right)}\right]+\left[{\mathrm{HF}}^{-}\right]+2\left[{\mathrm{HF}}_2^{-}\right]}} \\ =\underset{\mathrm{species}\mathrm{containing}{\mathrm{Ca}}^{2+}}{\underbrace{2\left\{\left[{\mathrm{Ca}}^{2+}\right]+\left[{\mathrm{CaOH}}^{+}\right]+\left[{\mathrm{CaF}}^{+}\right]+2\left[{\mathrm{CaF}}_{2\left(\mathrm{aq}\right)}\right]\right\}}} \end{gathered}$$

Charge and mass balances for calcium fluoride dissolution$\left({\mathrm{CaF}}_2\right)$ it was provided in water.