Reactions of acids

Excess hydrochloric acid in the stomach can cause pain. The excess hydrochloric acid can be neutralised by a calcium carbonate tablet.

A student investigated how the pH changed when a calcium carbonate tablet was added to hydrochloric acid.

This is the method used.

1. Add 10 cm³ of hydrochloric acid to a beaker.

2. Measure the pH of the hydrochloric acid using an indicator.

3. Add a calcium carbonate tablet to the hydrochloric acid.

4. Time for 3 minutes.

5. Measure the pH of the mixture using an indicator.

Which two of the following pieces of equipment are needed in this method?

Tick (✓) two boxes.

Measuring cylinder

Newtonmeter

Ruler

Stop clock

Thermometer

Name an indicator used to measure pH.

Name a piece of equipment that gives a more accurate pH value than an indicator.

The word equation for the reaction is:

calcium carbonate + hydrochloric acid calcium chloride + water + carbon dioxide

Why is fizzing seen during the reaction?

Give one safety precaution the student should have taken.

What is the pH of a neutral solution?

Tick (✓) one box.

1 4 7 10

A student reacted hydrochloric acid with excess calcium carbonate.

A solution of calcium chloride was produced.

Figure 5 shows the method used to produce calcium chloride crystals from the reaction mixture.

Describe the method shown in Figure 5 to produce calcium chloride crystals from the reaction mixture.

Include the equipment used.

This question is about hydrocarbon fuels.

The complete combustion of a hydrocarbon fuel produces carbon dioxide and one other product.

Name the other product of the complete combustion of a hydrocarbon fuel.

Do not refer to carbon dioxide.

Describe the test for carbon dioxide.

Give the result if carbon dioxide is present.

The combustion of hydrocarbon fuels releases energy.

A student investigated the energy released by three different fuels A, B and C.

Figure 11 shows the apparatus.

This is part of the method used.

1. Put fuel A in the burner.

2. Pour 100 cm³ of water into the conical flask.

3. Record the temperature of the water.

4. Light the fuel and heat the water for 5 minutes.

5. Record the final temperature of the water.

6. Repeat steps 1 to 5 using fuel B and then using fuel C.

The student also determined the mass of fuel burnt.

Describe how the student could determine the mass of fuel burnt.

Give one control variable in the investigation.

Table 5 shows the results.

Explain how Table 5 shows that fuel C released the most energy per gram of fuel.

The student repeated the investigation with screens around the apparatus.

Figure 12 shows the apparatus with screens.

Give one reason why putting screens around the apparatus could improve the accuracy of the investigation.

How would stirring the water improve the accuracy of the investigation?

This question is about hydrocarbon fuels.

The complete combustion of a hydrocarbon fuel produces carbon dioxide and one other product.

Name the other product of the complete combustion of a hydrocarbon fuel.

Do not refer to carbon dioxide.

Describe the test for carbon dioxide.

Give the result if carbon dioxide is present.

The combustion of hydrocarbon fuels releases energy.

A student investigated the energy released by three different fuels A, B and C.

Figure 1 shows the apparatus.

This is part of the method used.

1. Put fuel A in the burner.

2. Pour 100 cm³ of water into the conical flask.

3. Record the temperature of the water.

4. Light the fuel and heat the water for 5 minutes.

5. Record the final temperature of the water.

6. Repeat steps 1 to 5 using fuel B and then using fuel C.

The student also determined the mass of fuel burnt.

Describe how the student could determine the mass of fuel burnt.

Give one control variable in the investigation.

Table 1 shows the results.

Explain how Table 1 shows that fuel C released the most energy per gram of fuel.

The student repeated the investigation with screens around the apparatus.

Figure 2 shows the apparatus with screens.

Give one reason why putting screens around the apparatus could improve the accuracy of the investigation.

How would stirring the water improve the accuracy of the investigation?

This question is about reactions of metals.

A piece of magnesium reacts with dilute hydrochloric acid.

Magnesium chloride solution and a gas are produced.

Which gas is produced?

Tick (✓) one box.

Chlorine

Hydrogen

Oxygen

Give two observations seen during the reaction.

Magnesium chloride is formed from Mg²⁺ ions and Cl^‒ ions.

What is the formula of magnesium chloride?

Tick (✓) one box.

MgCl MgCl₂ Mg₂Cl Mg₂Cl₂

Calcium is in the same group as magnesium in the periodic table.

What is the symbol for a calcium ion?

Tick (✓) one box.

Ca⁺ Ca^‒ Ca²⁺ Ca^2‒

Figure 2 shows a cube of calcium.

How would you calculate the total surface area of this cube?

Tick (✓) one box.

Total surface area = 2 × 2 × 2

Total surface area = 2 × 2 × 4

Total surface area = 2 × 2 × 6

Total surface area = 2 × 4 × 6

A teacher investigated the reaction between calcium and water.

The teacher used the same mass of three different forms of calcium.

The different forms of calcium were: powder small lumps large lumps.

The teacher measured the time for each reaction to be complete.

What is the independent variable in the investigation?

Tick (✓) one box.

Form of calcium

Mass of calcium

Time for reaction to be complete

Which form of calcium will react the fastest?

Tick (✓) one box.

Powder

Small lumps

Large lumps

Which is the best way to display the results for the three different forms of calcium?

Tick (✓) one box.

Bar chart

Line graph

Pie chart

This question is about the reaction between copper carbonate and nitric acid.

Carbon dioxide is produced when copper carbonate reacts with nitric acid.

Give the test for carbon dioxide gas.

Give the result of the test if carbon dioxide is present.

The word equation for the reaction between copper carbonate and nitric acid is:

copper carbonate + nitric acid X + Y + carbon dioxide

Name the products X and Y.

A student investigated the rate of the reaction between copper carbonate and nitric acid.

Describe a method to show the effect of changing the temperature of the nitric acid on the rate of reaction.

Your method should include measuring the volume of carbon dioxide gas produced.

The student concluded that:

‘An increase in temperature increases the rate of reaction.’

The student’s conclusion was correct.

Explain why an increase in temperature increases the rate of reaction.

You should refer to particles and collisions in your answer.

This question is about the reaction between copper carbonate and nitric acid.

Carbon dioxide is produced when copper carbonate reacts with nitric acid.

Give the test for carbon dioxide gas.

Give the result of the test if carbon dioxide is present.

The word equation for the reaction between copper carbonate and nitric acid is:

copper carbonate + nitric acid X + Y + carbon dioxide

Name the products X and Y.

A student investigated the rate of the reaction between copper carbonate and nitric acid.

Describe a method to show the effect of changing the temperature of the nitric acid on the rate of reaction.

Your method should include measuring the volume of carbon dioxide gas produced.

The student concluded that:

‘An increase in temperature increases the rate of reaction.’

The student’s conclusion was correct.

Explain why an increase in temperature increases the rate of reaction.

You should refer to particles and collisions in your answer.

This question is about the reaction of metals with sulfuric acid.

The word equation for the reaction of zinc with sulfuric acid is:

zinc + sulfuric acid → zinc sulfate + hydrogen

What type of substance is zinc sulfate?

Tick (✓) one box.

Calculate the relative formula mass (M_r) of zinc sulfate (ZnSO₄).

Relative atomic masses (A_r): Zn = 65 S = 32 O = 16

A student investigated the temperature increase when the same mass of different metals were added to 0.1 M sulphuric acid.

The student used four different metals.

The student did the experiment three times for each metal and calculated the mean temperature increase for each metal.

Table 5 shows the results for nickel.

Calculate value X.

Table 6 shows the mean values for the four metals.

The student plotted the results on a bar chart.

Figure 9 shows the bar chart.

The student made some errors when plotting the bar chart.

Give three errors the student made.

Use Table 6 to place the metals in order of reactivity.

A student investigated the rate of the reaction between magnesium and hydrochloric acid.

The reaction produced a gas.

Which gas is produced in the reaction?

Tick (✓) one box.

Figure 1 shows the apparatus used.

What is the piece of equipment labelled A ?

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The student saw that a chemical reaction was taking place.

Give two observations that would show a chemical reaction was taking place.

At the start of the investigation the volume of gas in the measuring cylinder was zero.

The student measured the volume of gas collected every 20 seconds for 2 minutes.

The readings for the volume of gas were 24 cm³, 44 cm³, 59 cm³, 70 cm³, 76 cm³ and 79 cm³

Complete Table 1.

How could the student make the reaction faster?

Tick (✓) one box.

The student repeated the investigation at a higher temperature.

Figure 2 shows the results.

Determine the mean rate of reaction for the first 10 seconds.

Use the equation:

Give the unit.

Choose the unit from the box.

Determine the time at which the reaction finished and no more gas was produced.

Use Figure 2.

Why does the rate of reaction increase when the temperature is higher?

Tick (✓) two boxes.

When a metal carbonate reacts with an acid, a salt, carbon dioxide and water are produced.

Describe how you would test for carbon dioxide gas.

Give the result of the test.

Describe how to make pure dry crystals of magnesium chloride from magnesium carbonate and a dilute acid.

In your method you should name the apparatus and reagents you plan to use.

When a metal carbonate reacts with an acid, a salt, carbon dioxide and water are produced.

Describe how you would test for carbon dioxide gas.

Give the result of the test.

Describe how to make pure dry crystals of magnesium chloride from magnesium carbonate and a dilute acid.

In your method you should name the apparatus and reagents you plan to use.

A teacher demonstrated the extraction of copper from copper oxide.

This is the method used.

1. Mix 1.30 g of zinc and 1.59 g of copper oxide.

2. Heat the mixture strongly.

3. When the mixture starts to glow, stop heating.

4. Let the glow spread through the mixture.

5. Leave the mixture to cool.

6. Add hydrochloric acid to the cooled mixture.

7. Filter the mixture obtained in step 6.

A student concluded that an exothermic reaction had taken place.

Explain how an observation made during the demonstration shows this.

The equation for the reaction between zinc and copper oxide is:

1.59 g of copper oxide reacted.

Calculate the mass of copper produced.

Relative atomic masses (A_r): Cu = 63.5 O = 16 Zn = 65

Explain why steps 6 and 7 result in only copper being obtained as the residue.

The ionic equation for the reaction is:

Which statement about the reaction between zinc and copper ions is correct?

Tick one box.