Mixtures and separation techniques

This question is about mixtures.

Draw one line from each type of mixture to the representation of that mixture.

A student had a mixture of salt and sand.

Salt is soluble in water.

Sand is insoluble in water.

Plan a method to obtain pure dry samples of salt and of sand from the mixture.

Figure 11 shows the chemicals and equipment that can be used.

A mixture of salt and sand contained 16.0 g of salt.

The student obtained 13.6 g of salt after separation from the mixture.

Calculate the percentage yield of the salt.

Use the equation

This question is about elements, compounds and mixtures.

Figure 1 shows diagrams which represent the atoms and molecules in different substances.

Which diagram in Figure 1 represents a pure compound?

Tick () one box.

Which diagram in Figure 1 represents a mixture of an element and a compound?

Tick () one box.

Elements are metals or non-metals.

Figure 2 shows an outline of the periodic table.

The periodic table is divided into sections.

Where are metals found in the periodic table?

Tick () one box.

Which two of the following are typical properties of a transition metal?

Tick () two boxes.

Potassium and chlorine react to produce potassium chloride.

An atom of potassium loses an electron to form a potassium ion.

An atom of chlorine gains an electron to form a chloride ion.

Complete the dot and cross diagram.

Mixtures are separated by different methods.

Figure 3 shows the apparatus for separating four different types of mixture.

Figure 3

Which apparatus could be used to collect water from sodium chloride solution?

Use Figure 3.

Tick () one box.

Which apparatus shows filtration?

Use Figure 3.

Tick () one box.

This question is about elements, compounds and mixtures.

Which type of substance is hydrogen?

Tick (✓) one box.

The diagrams in Figure 2 represent different substances.

represent atoms of three different elements.

Use Figure 2 to answer questions 02.2 and 02.3.

Which diagram represents a mixture of compounds?

Which diagram represents a mixture of elements?

Substances can be separated from mixtures by using different methods.

Complete the sentence.

Sand can be separated from a mixture of sand and water by

A mixture of four liquids was fractionally distilled.

Figure 3 shows the apparatus used.

Table 2 shows the boiling points of the four liquids in the mixture.

Which liquid in Table 2 would distil and be collected in the beaker first?

Suggest what would happen to the temperature of the water as the water flows through the condenser.

Describe how to obtain sodium chloride crystals from sodium chloride solution by crystallisation.

This question is about aluminium.

Aluminium is a metal. Draw one line from each property of aluminium to the correct reason for that property.

Property Reason

Aluminium can be used to make alloys. What is meant by an ‘alloy’?

Aluminium is extracted from bauxite. Bauxite is a mixture which contains aluminium oxide.

Bauxite contains between 15% and 25% aluminium. Aluminium oxide always contains 53% aluminium. How does this show that bauxite is a mixture and not a compound?

The waste material from the bauxite is stored in lakes of mud. The lakes of mud are held in place by dams. Figure 6 shows one of these lakes.

Suggest two possible problems with storing the waste material in lakes of mud.

Aluminium is extracted by electrolysis. The aluminium oxide is mixed with cryolite and melted. The mixture is then electrolysed.

The formula of cryolite is Na₃AlF₆ Give the total number of atoms in the formula.

What is the reason for adding cryolite to the aluminium oxide? Tick (✓) one box.

Complete the sentences. Choose answers from the box.

When the molten aluminium oxide and cryolite mixture is electrolysed the product

This product reacts with the positive electrode because the positive electrode is

A sample of bauxite contains 25% aluminium. Calculate the maximum mass of aluminium that can be extracted from 300 000 kg of the sample of bauxite. Give your answer in standard form.

This question is about silver iodide. Silver iodide is produced in the reaction between silver nitrate solution and sodium iodide solution. The equation for the reaction is: AgNO₃(aq) + NaI(aq) → AgI(s) + NaNO₃(aq)

A student investigated the law of conservation of mass. This is the method used.

1. Pour silver nitrate solution into a beaker labelled A.

2. Pour sodium iodide solution into a beaker labelled B.

3. Measure the masses of both beakers and their contents.

4. Pour the solution from beaker B into beaker A.

5. Measure the masses of both beakers and their contents again.

Table 7 shows the student’s results.

Explain how the results demonstrate the law of conservation of mass. You should use data from Table 7 in your answer.

Suggest how the student could separate the insoluble silver iodide from the mixture at the end of the reaction.

The student purified the separated silver iodide. This is the method used.

1. Rinse the silver iodide with distilled water.

2. Warm the silver iodide.

Suggest one impurity that was removed by rinsing with water.

Suggest why the student warmed the silver iodide.

Calculate the percentage atom economy for the production of silver iodide in this reaction. The equation for the reaction is: AgNO₃(aq) + NaI(aq) → AgI(s) + NaNO₃(aq) Give your answer to 3 significant figures. Relative formula masses (M_r): AgNO₃ = 170 NaI = 150 AgI = 235 NaNO₃ = 85

Give one reason why reactions with a high atom economy are used in industry.

This question is about silver iodide. Silver iodide is produced in the reaction between silver nitrate solution and sodium iodide solution. The equation for the reaction is: AgNO₃(aq) + NaI(aq) → AgI(s) + NaNO₃(aq)

A student investigated the law of conservation of mass. This is the method used.

1. Pour silver nitrate solution into a beaker labelled A.

2. Pour sodium iodide solution into a beaker labelled B.

3. Measure the masses of both beakers and their contents.

4. Pour the solution from beaker B into beaker A.

5. Measure the masses of both beakers and their contents again.

Table 3 shows the student’s results.

Explain how the results demonstrate the law of conservation of mass. You should use data from Table 3 in your answer.

Suggest how the student could separate the insoluble silver iodide from the mixture at the end of the reaction.

The student purified the separated silver iodide. This is the method used.

1. Rinse the silver iodide with distilled water.

2. Warm the silver iodide.

Suggest one impurity that was removed by rinsing with water.

Suggest why the student warmed the silver iodide.

Calculate the percentage atom economy for the production of silver iodide in this reaction. The equation for the reaction is: AgNO₃(aq) + NaI(aq) → AgI(s) + NaNO₃(aq) Give your answer to 3 significant figures. Relative formula masses (M_r): AgNO₃ = 170 NaI = 150 AgI = 235 NaNO₃ = 85

Give one reason why reactions with a high atom economy are used in industry.

This question is about elements, compounds and mixtures. Figure 5 shows five different substances, A, B, C, D and E.

Use Figure 5 to answer Questions 03.1 to 03.3

Which substance is only one compound? Tick (✓) one box.

Which substance is a mixture of elements? Tick (✓) one box.

Which substance is a mixture of an element and a compound? Tick (✓) one box.

Substances are separated from a mixture using different methods.

Draw one line from each method of separation to the substance and mixture it would separate.

Method of separation Substance and mixture

Sand does not dissolve in water. A student separates a mixture of sand and water by filtration. Draw a diagram of the apparatus the student could use. You should label:

• where the sand is collected

• where the water is collected.

Diagram

A student distils a sample of salt solution to produce pure water. Figure 6 shows the apparatus.

What temperature would you expect the thermometer to show?

Tick (✓) one box.

Describe how the process of distillation shown in Figure 6 produces pure water from salt solution.

This question is about mixtures.

Substances are separated from a mixture using different methods.

Draw one line from each substance and mixture to the best method of separation.

Substance and mixture
Method of separation

A student filters a mixture.

Figure 1 shows the apparatus.

Suggest one improvement to the apparatus.

Complete the sentences.

Choose answers from the box.

Figure 2 shows the arrangement of atoms in a pure metal and in a mixture of metals.

Calculate the percentage of metal B atoms in the mixture of metals shown in Figure 2.

What is a mixture of metals called?

Tick one box.

Why is the mixture of metals in Figure 2 harder than the pure metal?

Tick one box.

A nanoparticle of pure metal A is a cube.

Each side of the cube has a length of 20 nm.

Figure 3 shows the cube.

What is the volume of the nanoparticle?

Tick one box.