Reactivity of metals

Cells contain chemicals that react to produce electricity.

A student investigated the voltage produced by four different cells.

Figure 3 shows the apparatus.

This is the method used.

1. Measure the voltage produced by the cell using metal A as the metal electrode.

2. Repeat using different metals as the metal electrode.

Table 2 shows the results.

Which substance could be used as the electrolyte in the cell in Figure 3 ?

Tick () one box.

Which metal A, B, C or D was copper?

Give one reason for your answer.

Use Figure 3 and Table 2.

Write the four metals A, B, C and D in order of reactivity.

Use Table 2.

A battery consists of several cells connected together in series.

Each cell has a voltage of 3.6 V.

Calculate the number of cells needed to make a battery of voltage 14.4 V.

Fuel cells can be used to power electric cars.

Complete the sentence.

Choose the answer from the box.

The overall reaction in a hydrogen fuel cell involves the oxidation of

Rechargeable cells can be recharged when an external electrical current is supplied.

Complete the sentence.

When an external electrical current is supplied to a rechargeable cell,

the chemical reaction is.

A student produced a salt by reacting copper carbonate with sulfuric acid.

This is the method used.

1. Measure 50 cm³ of sulfuric acid into a beaker.

2. Add copper carbonate powder.

3. Stir the mixture.

4. Repeat steps 2 and 3 until copper carbonate is in excess.

5. Filter the mixture.

6. Warm the filtrate gently until crystals start to appear.

7. Leave the solution to cool and crystallise.

Complete the word equation for the reaction.

copper + sulfuric → + + carbon

Give one observation the student could make during Step 4 which shows that the copper carbonate is in excess.

Give one reason for filtering the mixture in Step 5.

Name the equipment that can be used to warm the filtrate gently in Step 6.

The maximum theoretical mass of the salt that could be produced using 50 cm³ of the sulfuric acid is 12.5 g.

The percentage yield of the salt is 92.8%.

Calculate the mass of salt actually produced.

Use the equation:

Some salts can be produced by reacting sulfuric acid with a metal.

Neither copper nor sodium is used to produce a salt with sulfuric acid.

Give one reason why each metal is not used.

A student produced a salt by reacting copper carbonate with sulfuric acid.

This is the method used.

1. Measure 50 cm³ of sulfuric acid into a beaker.

2. Add copper carbonate powder.

3. Stir the mixture.

4. Repeat steps 2 and 3 until copper carbonate is in excess.

5. Filter the mixture.

6. Warm the filtrate gently until crystals start to appear.

7. Leave the solution to cool and crystallise.

Complete the word equation for the reaction.

copper + sulfuric → + + carbon

Give one observation the student could make during Step 4 which shows that the copper carbonate is in excess.

Give one reason for filtering the mixture in Step 5.

Name the equipment that can be used to warm the filtrate gently in Step 6.

The maximum theoretical mass of the salt that could be produced using 50 cm³ of the sulfuric acid is 12.5 g.

The percentage yield of the salt is 92.8%.

Calculate the mass of salt actually produced.

Use the equation:

Some salts can be produced by reacting sulfuric acid with a metal.

Neither copper nor sodium is used to produce a salt with sulfuric acid.

Give one reason why each metal is not used.

A student investigated the voltage produced by different pairs of metal electrodes in a chemical cell.

Figure 6 shows the apparatus.

This is the method used.

1. Place a nickel electrode and an electrode made from a different metal (electrode A in 1.0 mol/dm³ sodium chloride solution.

2. Measure the voltage produced.

3. Repeat using different metals for electrode A.

Table 3 shows the results.

Write the symbols of the five metals in Table 3 in order of reactivity.

Justify your answer.

Most reactive Least reactive

The voltage produced by a chemical cell depends on the concentration of the electrolyte solution.

Plan an experiment to investigate how the voltage produced by a chemical cell varies with the concentration of the electrolyte solution.

The following substances are available:

• the metal electrodes in Table 3

• 1.0 mol/dm³ sodium chloride solution

• pure water.

Describe how a hydrogen fuel cell produces a potential difference.

This question is about acids and their reactions.

Acids can be either weak or strong.

What is meant by ‘a weak acid’?

Explain what happens to the pH of an acid as the acid is diluted with water.

A student does a titration to find the volume of acid needed to neutralise an alkali.

The student fills a burette with the acid.

Give three more steps the student must do before adding the acid to the alkali from the burette.

You should name any equipment used.

The student titrated a solution containing 0.0045 moles of sodium hydroxide with 0.15 mol/dm³ hydrochloric acid.

The equation for the reaction is:

Calculate the volume of hydrochloric acid in cm³ needed in the titration.

A calcium atom is larger than a magnesium atom.

Explain why calcium reacts more vigorously than magnesium with hydrochloric acid of the same concentration.

This question is about metals.

Platinum is used to make jewellery. Suggest one reason why platinum is used to make jewellery.

Figure 7 shows a piece of sodium being added to water.

Give two observations that could be seen when sodium is added to water.

Copper is a transition element. Sodium is a Group 1 element. What are two differences between copper and sodium? Tick (✓) two boxes.

The metals aluminium and copper can be used to make pans for cooking. Table 2 shows information about the two metals. The higher the value for thermal conductivity, the better the metal conducts thermal energy.

Evaluate the use of pans made of aluminium and of copper. Use Table 2.

This question is about displacement reactions.

Iron is extracted from iron oxide by a displacement reaction with carbon.

Balance the equation for the reaction.

Iron oxide is reduced in this reaction. How does the equation show that iron oxide is reduced?

Calculate the relative formula mass (M_r) of Fe₂O₃ Relative atomic masses (A_r): O = 16 Fe = 56

Copper oxide reacts with hydrogen to produce copper. The equation for the reaction is:

Calculate the percentage atom economy for obtaining copper from this reaction. Use the equation:

Relative atomic mass (A_r): Cu = 63.5 Relative formula masses (M_r): H₂ = 2 CuO = 79.5

A student investigated the reactivity of four different metals, A, B, C and D. The student:

• added each metal to aqueous solutions of each of the metal sulfates

• observed whether a reaction took place.

Give one observation that would show a reaction took place.

Table 4 shows the results.

shows that a displacement reaction took place. × shows that a displacement reaction did not take place. Write metals A, B, C and D in order of reactivity. Give a reason for your order of reactivity.

This question is about displacement reactions.

Iron is extracted from iron oxide by a displacement reaction with carbon. The equation for the reaction is:

Which substance in the equation is reduced? Give one reason for your answer. Answer in terms of oxygen.

Which expression shows how to calculate the mass of carbon needed to produce 1 mole of iron from iron oxide? Relative atomic mass (A_r): C = 12 Tick (✓) one box.

A student investigated displacement reactions of four different metals represented by A, B, C and D. A, B, C and D are not the actual chemical symbols for the metals. The student:

• added each metal to aqueous solutions of the metal nitrates

• observed whether a reaction took place.

Table 6 shows information about three of the reaction mixtures.

The ionic equation for Reaction 1 is:

Why is this a redox reaction?

Tick () one box.

Which of the four metals has the greatest tendency to form positive ions? Use Table 6. Tick (✓) one box.

The nitrate ion has the formula NO₃^– Which of the four metals could be aluminium? Explain your answer. Use Table 6.

Metal X is extracted from an oxide of metal X by reaction with hydrogen. The equation for the reaction is:

The percentage atom economy for obtaining metal X by this method is 77.3%. Calculate the relative atomic mass (A_r) of metal X. Relative atomic masses (A_r): H = 1 O = 16

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?

Tick (✓) one box.

Which metal is the most reactive?

Tick (✓) one box.

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?

Tick (✓) one box.

This question is about zinc and compounds of zinc. A student produces pure crystals of zinc chloride by reacting zinc oxide with hydrochloric acid. The equation for the reaction is:

The student adds zinc oxide to hydrochloric acid until the zinc oxide is in excess. Give one observation that the student could make to show that the zinc oxide is in excess.

Why is excess zinc oxide used rather than excess hydrochloric acid?

Name one other compound that the student could add to hydrochloric acid to produce zinc chloride.

Describe how the student should obtain crystals of zinc chloride from a solution of zinc chloride.

Zinc chloride is also produced in a displacement reaction between zinc and copper chloride solution. The equation for the reaction is:

Complete the ionic equation for this reaction.

Why is zinc described as being oxidised in this reaction?

Zinc and copper can be used with another substance to produce electricity. Complete Figure 7 to show how zinc, copper and another substance can be used to light a lamp. Label:

• zinc

• copper

• the other substance used.

The symbol represents the lamp.

This question is about silicon and compounds of silicon.

The reactivity series sometimes includes non-metals such as carbon, hydrogen and silicon. Silicon can be extracted by reducing silicon dioxide with different substances. The equation for one possible reaction is:

Explain what this reaction shows about the position of silicon in the reactivity series.

Aluminium also reduces silicon dioxide. Carbon is used rather than aluminium to reduce silicon dioxide because carbon is cheaper than aluminium. Carbon can be obtained by heating coal. Aluminium is obtained from aluminium oxide. Explain why aluminium is more expensive than carbon.

Magnesium also reduces silicon dioxide. The equation for the reaction is:

Give one reason why the products are difficult to separate if magnesium is used to reduce silicon dioxide.

Calculate the minimum mass in grams of magnesium needed to completely reduce 1.2 kg of silicon dioxide. Relative atomic masses (A_r): O = 16 Mg = 24 Si = 28

Si₂H₆ is a covalent compound of silicon and hydrogen.

Complete Figure 9 to show the outer shell electrons in a molecule of Si₂H₆

Si₂H₆ reacts with oxygen. The equation for the reaction is:

30 cm³ of Si₂H₆ is reacted with 150 cm³ (an excess) of oxygen.

Calculate the total volume of gases present after the reaction. All volumes of gases are measured at the same temperature and pressure.

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?

Tick (✓) one box.

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 ?

Choose answers from the box.

This question is about metals.

Table 3 shows information about four substances.

Which substance could be a metal? Tick (✓) one box.

Explain why alloys are harder than pure metals.

A student wants to compare the reactivity of an unknown metal, Q, with that of zinc. Both metals are more reactive than silver. The student is provided with:

• silver nitrate solution

• metal Q powder

• zinc powder

• a thermometer

• normal laboratory equipment.

No other chemicals are available. Describe a method the student could use to compare the reactivity of metal Q with that of zinc. Your method should give valid results.

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.

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 2 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.

This question is about chemical cells. A student investigated the voltage produced by different chemical cells. Figure 9 shows the apparatus.

This is the method used.

1. Use cobalt as electrode X.

2. Record the cell voltage.

3. Repeat steps 1 and 2 using different metals as electrode X.

Suggest two control variables used in this investigation.

Table 4 shows the student’s results.

Write the six metals used for electrode X in order of reactivity. Use Table 4. Justify your order of reactivity.

Which of the following pairs of metals would produce the greatest voltage when used as the electrodes in the cell? Use Table 4. Tick (✓) one box.

Hydrogen fuel cells can be used to power different forms of transport. Some diesel trains are being converted to run on hydrogen fuel cells. A newspaper article referred to the converted trains as the new ‘steam trains’. Suggest why.

A student investigated the temperature change in displacement reactions between metals and copper sulfate solution.

This is the method used.

1. Measure 50 cm³ of the copper sulfate solution into a polystyrene cup.

2. Record the starting temperature of the copper sulfate solution.

3. Add the metal and stir the solution.

4. Record the highest temperature the mixture reaches.

5. Calculate the temperature increase for the reaction.

6. Repeat steps 1-5 with different metals.

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

The student used a polystyrene cup and not a glass beaker.

Why did this make the investigation more accurate?

Tick one box.

Table 5 shows the student’s results.

Complete Figure 9.

Use data from Table 5.

The student concluded that the reactions between the metals and copper sulfate solution are endothermic.

Give one reason why this conclusion is not correct.

The temperature increase depends on the reactivity of the metal.

Write the metals magnesium, nickel and zinc in order of reactivity.

Use Table 5.

Y is an unknown metal.

Describe a method to find the position of Y in the reactivity series in Question 06.5

Figure 10 shows the reaction profile for the reaction between zinc and copper sulfate solution.

Which letter represents the products of the reaction?

Tick one box.

Which letter represents the activation energy?

Tick one box.

This question is about elements in Group 1.

A teacher burns sodium in oxygen.

What is the name of this type of reaction?

Tick one box.

The teacher dissolves the product of the reaction in water and adds universal indicator.

The universal indicator turns purple.

What is the pH value of the solution?

Tick one box.

The solution contains a substance with the formula NaOH

Give the name of the substance.

All alkalis contain the same ion.

What is the formula of this ion?

Tick one box.

A solution of NaOH had a concentration of 40 g/dm³

What mass of NaOH would there be in 250 cm³ of the solution?

The melting points of the elements in Group 1 show a trend.

Table 6 shows the atomic numbers and melting points of the Group 1 elements.

Plot the data from Table 6 on Figure 11.

Predict the melting point, X, of rubidium, atomic number 37

Use Figure 11.

A student investigated the temperature change in displacement reactions between metals and copper sulfate solution. Table 2 shows the student’s results.

Plot the data from Table 2 on Figure 4 as a bar chart.

The student concluded that the reactions between the metals and copper sulfate solution are endothermic. Give one reason why this conclusion is not correct.

The temperature change depends on the reactivity of the metal. The student’s results are used to place copper, iron, magnesium and zinc in order of their reactivity. Describe a method to find the position of an unknown metal in this reactivity series. Your method should give valid results.

Draw a fully labelled reaction profile for the reaction between zinc and copper sulfate solution on Figure 5.

Titanium is a transition metal. Titanium is extracted from titanium dioxide in a two stage industrial process. Stage 1 TiO₂ + 2 C + 2 Cl₂ TiCl₄ + 2 CO Stage 2 TiCl₄ + 4 Na Ti + 4 NaCl

Suggest one hazard associated with Stage 1.

Water must be kept away from the reaction in Stage 2. Give one reason why it would be hazardous if water came into contact with sodium.

Suggest why the reaction in Stage 2 is carried out in an atmosphere of argon and not in air.

Titanium chloride is a liquid at room temperature. Explain why you would not expect titanium chloride to be a liquid at room temperature.

In Stage 2, sodium displaces titanium from titanium chloride.

Sodium atoms are oxidised to sodium ions in this reaction. Why is this an oxidation reaction?

Complete the half equation for the oxidation reaction.

In Stage 2, 40 kg of titanium chloride was added to 20 kg of sodium. The equation for the reaction is:

Relative atomic masses (A_r): Na = 23 Cl = 35.5 Ti = 48 Explain why titanium chloride is the limiting reactant. You must show your working.

For a Stage 2 reaction the percentage yield was 92.3% The theoretical maximum mass of titanium produced in this batch was 13.5 kg. Calculate the actual mass of titanium produced.