Question

before beginning this experiment in the laboratory, you should be able to answer the following questions.

1. write molecular, complete ionic, and net ionic equations for the reactions that occur, if any, when solutions of the following substances are mixed:

(a) nitric acid and potassium carbonate
(b) sodium bromide and lead nitrate
(c) acetic acid and calcium hydroxide
(d) calcium nitrate and sodium sulfate
(e) ammonium chloride and lithium hydroxide

1. which of the following are not water - soluble: ba(no₃)₂, fecl₃, cuco₃, cuso₄, zns, and znso₄?
2. write equations for the decomposition of h₂co₃ and h₂so₃.
3. at what temperature (from your graph) do kno₃ and nacl have the same molar solubility?

Explanation:

Step1: Write molecular equations

Based on reaction types and product formation.

Step2: Write complete ionic equations

Dissociate aqueous ionic compounds into ions.

Step3: Write net ionic equations

Cancel out spectator ions.

Step4: Determine water - solubility

Apply solubility rules.

Step5: Write decomposition equations

Based on common decomposition products of acids.

Step6: Analyze solubility graph

Find intersection of curves for equal molar solubility.

Answer:

1.

(a)

Molecular equation: $2HNO_3(aq)+K_2CO_3(aq)=2KNO_3(aq)+H_2O(l)+CO_2(g)$
Complete - ionic equation: $2H^+(aq)+2NO_3^-(aq)+2K^+(aq)+CO_3^{2 - }(aq)=2K^+(aq)+2NO_3^-(aq)+H_2O(l)+CO_2(g)$
Net - ionic equation: $2H^+(aq)+CO_3^{2 - }(aq)=H_2O(l)+CO_2(g)$

(b)

Molecular equation: $2NaBr(aq)+Pb(NO_3)_2(aq)=PbBr_2(s)+2NaNO_3(aq)$
Complete - ionic equation: $2Na^+(aq)+2Br^-(aq)+Pb^{2 + }(aq)+2NO_3^-(aq)=PbBr_2(s)+2Na^+(aq)+2NO_3^-(aq)$
Net - ionic equation: $Pb^{2 + }(aq)+2Br^-(aq)=PbBr_2(s)$

(c)

Molecular equation: $2CH_3COOH(aq)+Ca(OH)_2(aq)=(CH_3COO)_2Ca(aq)+2H_2O(l)$
Complete - ionic equation: $2CH_3COOH(aq)+Ca^{2 + }(aq)+2OH^-(aq)=2CH_3COO^-(aq)+Ca^{2 + }(aq)+2H_2O(l)$
Net - ionic equation: $CH_3COOH(aq)+OH^-(aq)=CH_3COO^-(aq)+H_2O(l)$

(d)

Molecular equation: $Ca(NO_3)_2(aq)+Na_2SO_4(aq)=CaSO_4(s)+2NaNO_3(aq)$
Complete - ionic equation: $Ca^{2 + }(aq)+2NO_3^-(aq)+2Na^+(aq)+SO_4^{2 - }(aq)=CaSO_4(s)+2Na^+(aq)+2NO_3^-(aq)$
Net - ionic equation: $Ca^{2 + }(aq)+SO_4^{2 - }(aq)=CaSO_4(s)$

(e)

Molecular equation: $NH_4Cl(aq)+LiOH(aq)=LiCl(aq)+NH_3(g)+H_2O(l)$
Complete - ionic equation: $NH_4^+(aq)+Cl^-(aq)+Li^+(aq)+OH^-(aq)=Li^+(aq)+Cl^-(aq)+NH_3(g)+H_2O(l)$
Net - ionic equation: $NH_4^+(aq)+OH^-(aq)=NH_3(g)+H_2O(l)$

2.

$CuCO_3$ and $ZnS$ are not water - soluble. According to solubility rules, most carbonates are insoluble (except those of alkali metals and ammonium), and most sulfides are insoluble (except those of alkali metals, alkaline earth metals, and ammonium).

3.

For $H_2CO_3$: $H_2CO_3(aq)=H_2O(l)+CO_2(g)$
For $H_2SO_3$: $H_2SO_3(aq)=H_2O(l)+SO_2(g)$

4.

This question requires a graph which is not provided. In general, you would find the intersection point of the solubility - temperature curves of $KNO_3$ and $NaCl$ on the graph, and the x - value (temperature) of that intersection point is the answer.