Reactions of acids

Metals react with acids to produce a salt and a gas.

Which salt is produced when magnesium reacts with hydrochloric acid?

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Which gas is produced when magnesium reacts with hydrochloric acid?

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A student investigated the temperature change in the reaction between metals and hydrochloric acid.

This is the method used.

1. Measure 25 cm³ of hydrochloric acid at 20 °C into a container.

2. Add 1 g of a metal.

3. Record the temperature change.

4. Repeat steps 1 to 3 using a different metal.

Draw one line from the type of variable to the name of the variable in the investigation.

Which container would be the most suitable to reduce energy transfer with the surroundings?

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Figure 1 shows part of the scale of the thermometer used in the investigation.

What is the resolution of the thermometer?

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The reaction between a metal and an acid is exothermic.

What happens to the temperature of the mixture during the reaction?

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Figure 2 shows the reaction profile for the reaction between a metal and an acid.

Which letter in Figure 2 represents the reactants?

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Which letter in Figure 2 represents the activation energy?

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Which letter in Figure 2 represents the overall energy change?

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A titration measures the volumes of an acid and an alkali that neutralise each other.

Figure 4 shows the apparatus used.

Name the pieces of equipment labelled A, B and C in Figure 4.

Choose answers from the box.

In Step 2 in Figure 4 the acid is added to the alkali until the solution is neutralised.

The volume of acid added is then read from equipment C.

Name a suitable indicator for use in Step 2 of the titration.

Give one observation that shows the alkali is neutralised.

Give two ways to make sure that the volume of acid added is accurate.

Figure 5 shows the reading on equipment C at the end of Step 2.

What is the reading on equipment C in Figure 5 ?

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A student did a different titration.

Table 1 shows the results.

Which two results should be used to calculate the mean volume of acid added?

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A salt is produced when an acid neutralises an alkali.

Barium chloride is a salt containing the ions Ba²⁺ and Cl_¯

What is the formula of barium chloride?

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This question is about elements in the periodic table.

Argon has the atomic number 18 Explain why argon does not form compounds. Answer in terms of electrons.

Phosphorus (P) is the element below nitrogen in the periodic table. Predict the formula of the compound formed between phosphorus and hydrogen.

Tellurium is the element with atomic number 52 Predict whether tellurium reacts with metals. Explain your answer. Answer in terms of the position of tellurium in the periodic table.

Barium (Ba) is an element in Group 2 of the periodic table. Barium reacts with hydrochloric acid.

Suggest two observations that could be made when barium reacts with hydrochloric acid.

Write a balanced symbol equation for the reaction between barium and hydrochloric acid.

This question is about acids.

A student added four metals, A, B, C and D to hydrochloric acid.

Figure 4 shows the rate of bubbling in each tube.

Use Figure 4 to answer questions 03.1 and 03.2.

Which metal is copper?

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Which metal is the most reactive?

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A metal oxide reacts with an acid to produce zinc sulfate and water.

Name the metal oxide and the acid used in this reaction.

Name of metal oxide

A student reacts an acid with an alkali in a titration.

What is the type of reaction when an acid reacts with an alkali?

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A student investigated the reaction of magnesium with hydrochloric acid.

Figure 7 shows the apparatus used.

This is the method used.

1. Set up the apparatus as shown in Figure 7.

2. Cut 10 mm of magnesium ribbon.

3. Remove the stopper.

4. Add the magnesium ribbon to the conical flask.

5. Replace the stopper as quickly as possible.

6. Record the final reading on the gas syringe when the reaction has stopped.

7. Repeat steps 1 to 6 three more times.

8. Repeat steps 1 to 7 with different lengths of magnesium ribbon.

Which gas is produced when magnesium reacts with hydrochloric acid?

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What was the independent variable in the investigation?

Give one control variable in the investigation.

Table 5 shows the results for one length of magnesium ribbon.

One of the results was anomalous.

Which trial in Table 5 gave an anomalous result?

Suggest one reason for the anomalous result in Table 5.

Table 6 shows the mean volume of gas produced for each length of magnesium ribbon.

Plot the data from Table 6 on Figure 8.

Draw a line of best fit.

Complete the sentence.

As the length of the magnesium ribbon increases, the mean volume of gas produced

A student investigated the reactivity of metals with hydrochloric acid.

This is the method used.

1. Measure 50 cm³ of hydrochloric acid into a polystyrene cup.

2. Measure the temperature of the hydrochloric acid.

3. Add one spatula of metal powder to the hydrochloric acid and stir.

4. Measure the highest temperature the mixture reaches.

5. Calculate the temperature increase for the reaction.

6. Repeat steps 1 to 5 three more times.

7. Repeat steps 1 to 6 with different metals.

Table 4 shows the student’s results.

Calculate the mean temperature increase X for magnesium in Table 4.

Do not include the anomalous result in your calculation.

Determine the order of reactivity for the metals cobalt, magnesium and zinc.

Use Table 4.

The range of measurements either side of the mean shows the uncertainty in the mean temperature increase.

Complete the sentence.

Use Table 4.

What type of variable is the volume of hydrochloric acid in this investigation?

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Suggest one way of improving step 3 in the method to give results which are more repeatable.

Figure 6 shows a reaction profile for the reaction of magnesium with hydrochloric acid.

What do labels A, B and C represent on Figure 6 ?

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This question is about acids and alkalis.

Which ion do acids produce in aqueous solution?

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Acids react with alkalis.

What is the name of this type of reaction?

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Balance the equation for the reaction between sulfuric acid and potassium hydroxide.

Universal indicator turns purple in potassium hydroxide solution.

What is the pH of the solution?

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A student does a titration to find the volume of sulfuric acid that reacts with 25 cm³ of potassium hydroxide solution.

Figure 7 shows the equipment used.

The 25 cm³ of potassium hydroxide solution is measured with the measuring cylinder.

Which piece of equipment could the student use to measure the 25 cm³ of potassium hydroxide solution more accurately?

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Describe how the student would use the equipment in Figure 7 to complete the titration.

This question is about metal carbonates.

A student investigated the reaction of copper carbonate with an acid.

Figure 8 shows the apparatus.

This is the method used.

1. Pour 25 cm³ of the acid into a conical flask.

2. Weigh 0.10 g of copper carbonate.

3. Remove the stopper and add the copper carbonate to the flask.

4. Quickly replace the stopper.

5. Record the maximum volume of gas collected in the gas syringe.

6. Repeat steps 1 to 5 with different masses of copper carbonate.

Figure 9 shows the gas syringe during the experiment.

What is the reading on the gas syringe?

The student plotted the results on a graph.

Figure 10 shows the student’s graph.

Determine the gradient of the line of best fit.

You should:

• calculate the values of the change in y and the change in x

• calculate the gradient of the line of best fit.

Copper chloride was produced in the reaction.

Which acid reacts with copper carbonate to produce copper chloride?

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The reaction between copper carbonate and the acid produced a gas.

What was the gas?

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A different student produced a pure, dry sample of copper chloride using the same reaction.

This is the method used.

1. Add excess copper carbonate to the acid.

2. Filter the mixture.

3. Heat the solution gently until crystals start to form.

4. Leave for 24 hours.

5. Remove the crystals.

6. Rinse with water and dry the crystals.

Why was the solution heated gently in step 3 ?

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How should the solution be heated gently in step 3 ?

This question is about salts.

Name the salt produced by the neutralisation of hydrochloric acid with potassium hydroxide.

Write an ionic equation for the neutralisation of hydrochloric acid with potassium hydroxide.

Soluble salts can be produced by reacting dilute hydrochloric acid with an insoluble solid. Copper, copper carbonate and copper oxide are insoluble solids. Which of these insoluble solids can be used to make a copper salt by reacting the solid with dilute hydrochloric acid? Tick (✓) one box.

A student makes crystals of magnesium sulfate. This is the method used.

1. Add sulfuric acid to a beaker.

2. Warm the sulfuric acid.

3. Add a spatula of magnesium oxide to the beaker.

4. Stir the mixture.

5. Repeat steps 3 and 4 until there is magnesium oxide remaining in the beaker.

6. Filter the mixture.

7. Evaporate the filtrate gently until crystals start to form.

8. Leave the solution to finish crystallising.

Give one reason for:

• step 2

• step 5

• step 6.

How should the filtrate be evaporated gently in step 7 ?

Iron chloride is produced by heating iron in chlorine gas. The equation for the reaction is:

Calculate the volume of chlorine needed to react with 14 g of iron. You should calculate:

• the number of moles of iron used

• the number of moles of chlorine that react with 14 g of iron

• the volume of chlorine needed.

Relative atomic mass (A_r): Fe = 56 The volume of 1 mole of gas = 24 dm³

This question is about acids, bases and salts.

Zinc nitrate is a salt. A student produces zinc nitrate using an acid and a base.

Which acid should the student use to produce zinc nitrate? Tick (✓) one box.

Which is a base the student could use to produce zinc nitrate? Tick (✓) one box.

Name the salt with the formula MgBr₂

A student investigated how pH changes during a titration. This is the method used.

1. Pour 25.0 cm³ of hydrochloric acid into a beaker.

2. Measure the pH of the hydrochloric acid with a pH probe.

3. Add 1.0 cm³ of sodium hydroxide solution from a burette.

4. Swirl the mixture.

5. Measure the pH of the mixture.

6. Repeat steps 3 to 5 until a total of 30.0 cm³ of sodium hydroxide solution has been added.

Figure 10 shows the student’s results.

Describe how the pH of the mixture changes as sodium hydroxide solution is added to hydrochloric acid. Use data from Figure 10 in your answer.

What volume of sodium hydroxide solution is needed to neutralise 25.0 cm³ of hydrochloric acid? Use Figure 10.

Figure 11 shows the colour of universal indicator at different pH values.

The student could have used universal indicator instead of a pH probe. Determine the colour of universal indicator when 10.0 cm³ of sodium hydroxide solution has been added to 25.0 cm³ of hydrochloric acid. Use Figure 10 and Figure 11.

The student used a pipette to measure 25.0 cm³ of hydrochloric acid. Figure 12 shows a pipette.

Calculate the percentage uncertainty in the volume measured using this pipette. Use the equation:

Give one advantage of using a pipette rather than using a measuring cylinder to measure the volume of hydrochloric acid.

This question is about metals and the reactivity series.

Which two statements are properties of most transition metals? Tick (✓) two boxes.

A student added copper metal to colourless silver nitrate solution. The student observed:

• pale grey crystals forming

• the solution turning blue.

Explain how these observations show that silver is less reactive than copper.

A student is given three metals, X, Y and Z to identify. The metals are magnesium, iron and copper. Plan an investigation to identify the three metals by comparing their reactions with dilute hydrochloric acid. Your plan should give valid results.

Metal M has two isotopes. Table 6 shows the mass numbers and percentage abundances of the isotopes.

Calculate the relative atomic mass (A_r) of metal M. Give your answer to 1 decimal place.

A student investigated the reaction between lumps of calcium carbonate and dilute hydrochloric acid. This is the method used.

1. Pour 100 cm³ of dilute hydrochloric acid into a conical flask.

2. Place the conical flask on a balance.

3. Add 2 g of calcium carbonate lumps to the conical flask.

4. Wait until the calcium carbonate stops reacting.

5. Record the decrease in mass of the conical flask and contents.

6. Repeat steps 1 to 5 three more times.

The equation for the reaction is:

What is the state symbol X in the equation? Tick (✓) one box.

Table 2 shows the student’s results.

Why does the mass of the conical flask and contents decrease during the reaction? Tick (✓) one box.

What is the range of the four results in Table 2 ?

Calculate the mean decrease in mass of the conical flask and contents. Do not include the anomalous result. Use Table 2.

A teacher demonstrated the investigation. The teacher used different masses of calcium carbonate. Figure 8 shows the teacher’s results.

What type of variable is the mass of calcium carbonate? Tick (✓) one box.

Use Figure 8 to answer Questions 05.6 and 05.7

Complete the sentence. As the mass of calcium carbonate used increases, the decrease in mass of

What is the decrease in mass of the conical flask and contents when a 3 g sample of calcium carbonate is used?

This question is about acids and alkalis.

Which ion do all acids produce in aqueous solution? Tick (✓) one box.

Calcium hydroxide solution reacts with an acid to form calcium chloride. Complete the word equation for the reaction.

A student investigates the volume of sodium hydroxide solution that reacts with 25.0 cm³ of dilute sulfuric acid. Figure 12 shows the apparatus the student uses.

Use Figure 12 to answer Questions 09.3 and 09.4

Name apparatus A.

What is the reading on apparatus A ?

The higher the concentration of a sample of dilute sulfuric acid, the greater the volume of sodium hydroxide needed to neutralise the acid. The student tested two samples of dilute sulfuric acid, P and Q. Describe how the student could use titrations to find which sample, P or Q, is more concentrated.

This question is about acids and alkalis.

Which ion do all acids produce in aqueous solution? Tick (✓) one box.

Calcium hydroxide solution reacts with an acid to form calcium chloride. Complete the word equation for the reaction.

A student investigates the volume of sodium hydroxide solution that reacts with 25.0 cm³ of dilute sulfuric acid. Figure 2 shows the apparatus the student uses.

Use Figure 2 to answer Questions 02.3 and 02.4

Name apparatus A.

What is the reading on apparatus A ?

The higher the concentration of a sample of dilute sulfuric acid, the greater the volume of sodium hydroxide needed to neutralise the acid. The student tested two samples of dilute sulfuric acid, P and Q. Describe how the student could use titrations to find which sample, P or Q, is more concentrated.

Soluble salts are formed by reacting metal oxides with acids.

Give one other type of substance that can react with an acid to form a soluble salt.

Calcium nitrate contains the ions Ca²⁺ and NO₃^–

Give the formula of calcium nitrate.

Describe a method to make pure, dry crystals of magnesium sulfate from a metal oxide and a dilute acid.