Edexcel GCSE Combined Science Paper 3: Chemistry 1 Foundation June 2023 question paper 1SC0/1CF

In an experiment, paper chromatography was used to separate the coloured dyes in four different inks, W, X, Y and Z.

Figure 1 shows the chromatogram at the end of the experiment.

The chromatogram shows that only one of the inks contains a single dye.

Which ink contains a single dye?

Which ink contains the greatest number of dyes?

The R_f value of a dye can be calculated using the equation

At the end of the chromatography one dye had moved 3.60 cm and the solvent front had moved 9.20 cm.

Calculate the R_f value for this dye.

Give your answer to 2 decimal places.

R_f =_........

The substance used as the solvent in the chromatography was heated for 8 minutes.

Figure 2 shows how the temperature of the substance changed with time.

From A to B the substance was a liquid.

From C to D the substance was a gas.

Give the name of the change when a liquid becomes a gas.

Use Figure 2 to give the temperature of the substance at 4 minutes.

_........ C

Use Figure 2 to give the time when the substance has completely changed into a gas.

_........ minutes

The temperature of the substance at A was 25C.

Calculate the temperature rise of the substance from A to D.

_........ C

This question is about electrolysis.

Which statement describes what happens during electrolysis?

Figure 3 shows the electrolysis of copper chloride solution.

Use the words from the box to complete the labelling of the diagram in Figure 3.

The products of the electrolysis shown in Figure 3 are solid X and gas Y.

Draw one straight line from each product to its name.

The experiment is repeated using powdered solid copper chloride instead of copper chloride solution.

Nothing happens and no products are formed.

Explain why nothing happens and no products are formed.

When lead nitrate solution and potassium chloride solution are mixed, potassium nitrate and a precipitate of lead chloride are formed.

Complete the word equation for this reaction.

lead nitrate +_{........ ........} + lead chloride

Lead nitrate is toxic.

Which hazard symbol should be on a container of lead nitrate?

A student put 5 cm³ of potassium carbonate solution into a test tube and added 2 cm³ of calcium nitrate solution.

A precipitate formed and was allowed to settle as shown in Figure 4.

The height of the precipitate was measured.

Give the name of the piece of apparatus the student should use to find the volume of the potassium carbonate solution.

The student repeated the experiment.

The results are shown in Figure 5.

Use the data in Figure 5 to calculate the mean height of the precipitate.

mean height of precipitate =_........ cm

Describe how a pure, dry sample of the precipitate could be obtained from the mixture in the test tube.

The student investigated whether increasing the volume of calcium nitrate solution increased the height of the precipitate formed.

They repeated the experiment using different volumes of calcium nitrate.

State one variable that should be controlled in this investigation.

Magnesium is a metal.

State one physical property of magnesium.

Which element is in the same group of the periodic table as magnesium? Use the periodic table to help you answer this question.

Magnesium atoms have 12 electrons.

Complete the electronic configuration of a magnesium atom.

The electronic configuration of a chlorine atom is 2.8.7

Explain how the electronic configuration of chlorine is linked to its period in the periodic table.

1.20 g of magnesium reacts completely with 3.55 g of chlorine to form magnesium chloride.

Calculate the empirical formula of the magnesium chloride.

(relative atomic masses: Mg = 24.0, C l = 35.5)

You must show your working.

empirical formula =_........

Sodium reacts with chlorine to form sodium chloride, which contains ionic bonds.

Hydrogen reacts with chlorine to form hydrogen chloride, which contains covalent bonds.

Figure 6 shows dot and cross diagrams of these compounds.

Describe the differences between an ionic bond and a covalent bond.

In an experiment, powdered calcium hydroxide was added to dilute hydrochloric acid and the pH was measured.

The method used was

step 1 measure 200 cm3³ dilute hydrochloric acid into a beaker

step 2 aadd 0.1 g of powdered calcium hydroxide to the beaker

step 3 find the pH of the mixture

step 4 repeat steps 2 and 3 until the pH stops changing.

State what should be done after step 2 to make sure that any reaction is complete.

Complete the word equation for the reaction.

calcium hydroxide + hydrochloric acid _........

Which row of the table shows the state symbols for powdered calcium hydroxide and dilute hydrochloric acid in the balanced chemical equation?

The results of the experiment are shown in Figure 7.

mass of calcium hydroxide added in grams

Figure 7

Using Figure 7, give the pH of the acid at the start of the experiment.

pH =_........

Using Figure 7, give the mass of calcium hydroxide required to make a neutral mixture.

mass of calcium hydroxide =_........ g

Explain why the pH starts at a low value and ends at a higher value.

State what should be used to measure the pH of the mixture in this experiment.

The calcium hydroxide used is corrosive to the eyes and an irritant to skin.

Using this information, state one safety precaution that should be taken during the experiment when using any corrosive substance.

Figure 8 shows part of the reactivity series of metals.

Which metal reacts when added to cold water?

A student investigates the reactivity of four different metals.

The student adds an equal‑sized piece of each metal to separate test tubes containing dilute hydrochloric acid.

The student’s observations for zinc and copper are recorded in Figure 9.

Use the information in Figure 8 and in Figure 9 to predict the observations for the reactions of magnesium and of iron with dilute hydrochloric acid.

magnesium

iron

When metals react with acids, hydrogen gas is produced.

Describe the test to show that the gas is hydrogen.

When magnesium reacts with hydrochloric acid, magnesium chloride and hydrogen are formed.

Complete the balanced equation for the reaction.

Mg +_........ HCl MgCl₂ +_........

*(c) There are three common methods of obtaining metals from the Earth’s crust:

• mine the pure metal

• mine the metal ore and heat it with carbon

• mine the metal ore and electrolyse the molten compound.

The method used to obtain a metal is linked to its position in the reactivity series of metals.

Aluminium, gold, iron, and silver are some commonly used metals.

Use the reactivity series in Figure 8 to state and explain the method chosen to obtain each of these four metals.