Making soluble salts

This question is about acids.

A student investigated the volume of an alkali needed to react completely with

Figure 10 shows the apparatus.

This is the method used.

1. Add 25 cm³ of the acid to a beaker.

2. Add a piece of universal indicator paper to the acid.

3. Add the alkali drop by drop to the acid until the universal indicator paper changes colour to green.

4. Record the number of drops of alkali added.

The method does not give an accurate volume of alkali needed to react completely with the acid.

Suggest two improvements to the method.

What is the pH of the solution when the universal indicator paper turns green?

Tick () one box.

What name is given to the reaction between an acid and an alkali?

Tick () one box.

Which ion do all acids contain?

Tick () one box.

Name the acid that reacts with sodium hydroxide to produce sodium nitrate.

Figure 11 shows a reaction profile for the reaction between an acid and an alkali.

What do labels A and B represent on Figure 11 ?

Choose the answers from the box.

Acids also react with insoluble solid substances to produce salt solutions.

When making a salt solution, excess solid is added to the acid.

Draw the apparatus used to separate the excess solid from the salt solution by filtration.

The apparatus should collect:

• the excess solid

• the salt solution.

Solid X reacts with hydrochloric acid to produce zinc chloride and hydrogen gas.

Name solid X.

A student prepared copper sulfate by reacting an acid with excess copper carbonate.

Figure 13 shows the first two stages in the preparation of copper sulfate.

What is the formula of the acid used to prepare copper sulfate?

Tick () one box.

Beaker N contained copper sulfate solution.

Describe how the student could produce copper sulfate crystals from the copper sulfate solution in beaker N.

A student investigated the thermal decomposition of copper carbonate.

Copper carbonate decomposes to form two products.

Figure 14 shows the apparatus.

This is the method used.

1. Add 1.2 g of copper carbonate to a test tube.

2. Heat the test tube and contents until the mass does not change.

3. Record the mass of the contents of the test tube after heating.

4. Repeat steps 1 to 3 with different masses of copper carbonate.

Table 7 shows the results.

Plot the data from Table 7 on Figure 15.

Draw a line of best fit.

Why does the mass of the contents of the test tube decrease in mass when copper carbonate is thermally decomposed?

A student prepared copper sulfate by reacting an acid with excess copper carbonate.

Figure 3 shows the first two stages in the preparation of copper sulfate.

What is the formula of the acid used to prepare copper sulfate?

Tick () one box.

Beaker N contained copper sulfate solution.

Describe how the student could produce copper sulfate crystals from the copper sulfate solution in beaker N.

A student investigated the thermal decomposition of copper carbonate.

Copper carbonate decomposes to form two products.

Figure 4 shows the apparatus.

This is the method used.

1. Add 1.2 g of copper carbonate to a test tube.

2. Heat the test tube and contents until the mass does not change.

3. Record the mass of the contents of the test tube after heating.

4. Repeat steps 1 to 3 with different masses of copper carbonate.

Table 1 shows the results.

Plot the data from Table 1 on Figure 5.

Draw a line of best fit.

Why does the mass of the contents of the test tube decrease in mass when copper carbonate is thermally decomposed?

This question is about salts. Green copper carbonate and sulfuric acid can be used to produce blue copper sulfate crystals.

Excess copper carbonate is added to sulfuric acid. Give three observations you would make.

How can the excess copper carbonate be removed?

The pH of the solution changes during the reaction. What is the pH of the solution at the end of the reaction?

Copper carbonate and sulfuric acid react to produce copper sulfate. What type of reaction is this?

Ammonium nitrate is a salt. Figure 13 shows the maximum mass of ammonium nitrate that can dissolve in 100 cm³ of water at different temperatures.

A student adds ammonium nitrate to water at 80 °C until no more dissolves. The student cools 100 cm³ of this solution of ammonium nitrate from 80 °C to 20 °C to produce crystals of ammonium nitrate.

Determine the mass of ammonium nitrate that crystallises on cooling 100 cm³ of this solution from 80 °C to 20 °C

This question is about salts. Green copper carbonate and sulfuric acid can be used to produce blue copper sulfate crystals.

Excess copper carbonate is added to sulfuric acid. Give three observations you would make.

How can the excess copper carbonate be removed?

The pH of the solution changes during the reaction. What is the pH of the solution at the end of the reaction?

Copper carbonate and sulfuric acid react to produce copper sulfate. What type of reaction is this?

Ammonium nitrate is a salt. Figure 1 shows the maximum mass of ammonium nitrate that can dissolve in 100 cm³ of water at different temperatures.

A student adds ammonium nitrate to water at 80 °C until no more dissolves. The student cools 100 cm³ of this solution of ammonium nitrate from 80 °C to 20 °C to produce crystals of ammonium nitrate.

Determine the mass of ammonium nitrate that crystallises on cooling 100 cm³ of this solution from 80 °C to 20 °C

Acids react to produce salts. Universal indicator is added to water and then nitric acid is added to the mixture.

Give the colour change when nitric acid is added to the mixture of universal indicator and water. Tick (✓) one box.

What happens to the pH of water when nitric acid is added? Tick (✓) one box.

What is the state symbol for nitric acid?

Zinc carbonate reacts with nitric acid.

The word equation for the reaction is: zinc carbonate + nitric acid → zinc nitrate + water + carbon dioxide white solid colourless solution

Give two observations that would be made when zinc carbonate is added to nitric acid until the zinc carbonate is in excess.

The formula of the zinc ion is Zn²⁺ The formula of the nitrate ion is NO₃^– What is the formula for zinc nitrate? Tick (✓) one box.

Acids react with insoluble metal oxides to produce salts. Plan a method to produce a pure, dry sample of the soluble salt copper chloride from an acid and a metal oxide.

Acids react to produce salts. Universal indicator is added to water and then nitric acid is added to the mixture.

Give the colour change when nitric acid is added to the mixture of universal indicator and water. Tick (✓) one box.

What happens to the pH of water when nitric acid is added? Tick (✓) one box.

What is the state symbol for nitric acid?

Zinc carbonate reacts with nitric acid.

The word equation for the reaction is: zinc carbonate + nitric acid → zinc nitrate + water + carbon dioxide white solid colourless solution

Give two observations that would be made when zinc carbonate is added to nitric acid until the zinc carbonate is in excess.

The formula of the zinc ion is Zn²⁺ The formula of the nitrate ion is NO₃^– What is the formula for zinc nitrate? Tick (✓) one box.

Acids react with insoluble metal oxides to produce salts. Plan a method to produce a pure, dry sample of the soluble salt copper chloride from an acid and a metal oxide.

This question is about acids and bases.

What is the pH of sulfuric acid? Tick (✓) one box.

An acid reacts with zinc to produce zinc chloride and hydrogen. Which acid reacts with zinc to produce zinc chloride? Tick (✓) one box.

What type of substance is zinc chloride? Tick (✓) one box.

An alkali is a base in solution. Which compound is an alkali? Tick (✓) one box.

The formula of the copper ion is Cu²⁺ The formula of the oxide ion is O^2– What is the formula of copper oxide? Tick (✓) one box.

A student reacts an acid with copper oxide.

The reaction between the acid and copper oxide is very slow at room temperature. How could the student speed up the reaction?

Complete the sentence to show how the student makes sure that all the acid reacts. Choose the answer from the box.

The student adds copper oxide to the acid until the copper oxide is.

The student filters the unreacted copper oxide from the solution. Which apparatus does the student use? Tick (✓) one box.

What process is used to produce crystals of a salt from a salt solution?

This question is about acids, alkalis and bases. A student reacted zinc oxide powder with hydrochloric acid to produce zinc chloride solution.

Complete the equation for the reaction by writing the state symbols.

Give one way that the student could speed up the reaction between zinc oxide powder and hydrochloric acid.

Hydrochloric acid was the limiting reactant.

How could the student know when all the hydrochloric acid has reacted?

How could the student obtain zinc chloride solution from the reaction mixture when all the hydrochloric acid has reacted?

Describe how zinc chloride crystals are produced from zinc chloride solution.

Sulfuric acid and sodium hydroxide react to produce sodium sulfate.

Sulfuric acid is gradually added to sodium hydroxide solution. The pH of the mixture changes as the sulfuric acid is added until in excess. Suggest the pH at:

• the start before sulfuric acid is added

• the end when sulfuric acid is in excess.

Complete the symbol equation for the preparation of sodium sulfate. You should balance the equation.

A solution of hydrochloric acid had a hydrogen ion concentration of 1.0 mol/dm³ Water was added to the hydrochloric acid until the pH increased by 1 What was the hydrogen ion concentration of the hydrochloric acid after water had been added? Tick (✓) one box.

This question is about salts and electrolysis. A student wants to make copper chloride crystals. The student adds excess copper oxide to some hot acid. The student stirs the mixture.

Which acid should the student use? Tick (✓) one box.

Suggest how the student would know that excess copper oxide has been added.

There are four more stages, A, B, C and D, to make copper chloride crystals. The stages A, B, C and D are not in the correct order. Stage A Partially evaporate by heating with a water bath Stage B Filter the mixture into an evaporating basin Stage C Leave to crystallise Stage D Remove and dry the crystals

Put stages A, B, C and D in the correct order.

Molten copper chloride can be electrolysed. State the product at each electrode when molten copper chloride is electrolysed.

Negative electrode Positive electrode

A solution of copper chloride is electrolysed. Figure 3 shows a graph of the increase in mass of the negative electrode. This increase is shown over a time of 10 minutes.

Calculate the gradient of the line in Figure 3. Use the equation:

Aluminium is produced by electrolysis of a molten mixture. Complete the sentence. Choose the answers from the box.

A student plans a method to prepare pure crystals of copper sulfate. The student’s method is:

1. Add one spatula of calcium carbonate to dilute hydrochloric acid in a beaker.

2. When the fizzing stops, heat the solution with a Bunsen burner until all the liquid is gone.

The method contains several errors and does not produce copper sulfate crystals. Explain the improvements the student should make to the method so that pure crystals of copper sulfate are produced.

A student plans a method to prepare pure crystals of copper sulfate. The student’s method is:

1. Add one spatula of calcium carbonate to dilute hydrochloric acid in a beaker.

2. When the fizzing stops, heat the solution with a Bunsen burner until all the liquid is gone.

The method contains several errors and does not produce copper sulfate crystals. Explain the improvements the student should make to the method so that pure crystals of copper sulfate are produced.