Edexcel GCSE Combined Science Paper 4: Chemistry 2 Foundation June 2019 question paper 1SC0/2CF

Plants release oxygen into the atmosphere.

What is the name of the process that releases oxygen into the atmosphere?

The atmosphere contains 21% of oxygen.

Figure 1 shows an incomplete bar chart of the main gases in the atmosphere.

Complete the bar chart by showing the percentage of oxygen in the atmosphere.

Calculate the volume of oxygen present in 300 cm³ of air.

(volumes are measured under the same conditions of temperature and pressure)

volume of oxygen =_........ cm³

An atom of an element has an atomic number and a mass number.

Draw one straight line from each of these to the numbers of subatomic particles it shows to be present in an atom.

number of subatomic particles in an atom

Which test shows a gas is oxygen?

Complete the following sentences.

The name given to group 7 in the periodic table is_........ .

The name given to group 0 in the periodic table is_........ .

Which of the following rows gives the colours of the group 7 elements chlorine and bromine at room temperature?

Figure 2 shows the melting and boiling points of bromine and iodine.

element	melting point in C	boiling point in C
bromine	–7	59
iodine	114	184

Using the information in Figure 2, which row shows the physical states of these elements at 50C?

The densities of some elements in group 0 are shown in Figure 3.

Use the information in Figure 3 to suggest the density of krypton.

density of krypton =_........ g cm^–3

For many years, argon was used to fill filament light bulbs.

A filament light bulb is shown in Figure 4.

When the bulb is in use the metal filament becomes extremely hot.

Explain why argon, rather than air, was used to fill filament light bulbs.

A student poured 50 cm³ water into a beaker and measured the water’s temperature.

The student added 1.00 g calcium chloride to the water, stirred the mixture and then recorded the temperature.

Give the name of the apparatus that could be used to measure 1.00 g of calcium chloride.

The student’s results were

temperature of water at start = 21C temperature of mixture after stirring = 32C

Explain, using these results, the type of heat energy change that occurs when calcium chloride dissolves in water.

Calcium chloride is hazardous to health.

Which hazard symbol would be expected to be seen on a container of calcium chloride?

Give a safety precaution that the student should take during the experiment.

State one way in which the apparatus could be changed to reduce the amount of heat energy lost during the experiment.

The concentration of a calcium chloride solution is 12 g dm^–3.

Calculate the volume of this solution, in cm³, that contains 9.0 g of calcium chloride.

You must show your working.

volume of solution =_........ cm³

The word equation for the reaction between magnesium and dilute hydrochloric acid is

magnesium + hydrochloric acid magnesium chloride + hydrogen

The reaction was carried out using the apparatus shown in Figure 6.

A strip of magnesium ribbon was placed in the conical flask. 100 cm³ of dilute hydrochloric acid was added to the conical flask.

The mass of the flask and contents was measured at regular intervals. The loss in mass was calculated. Figure 7 shows a graph of the results.

Name the apparatus that could be used to measure out 100 cm³ of dilute hydrochloric acid.

Explain why there is a loss in mass of the flask and contents.

The graph shows that the rate of reaction slows as the reaction takes place.

Explain, in terms of particles, why the rate of reaction between magnesium ribbon and dilute hydrochloric acid slows as the reaction takes place.

The experiment was repeated using the acid at a higher temperature. All other conditions were kept the same.

State the effect of the higher temperature on the mass loss after two minutes.

The original experiment was repeated using the same mass of magnesium powder instead of the magnesium ribbon. All other conditions were kept the same.

Sketch, on the graph in Figure 7, the line you would expect for this experiment.

Some reactions are affected by the presence of a catalyst.

State the effect of a catalyst on a reaction.

Devise a simple experiment to find out what happens to the mass of a solid catalyst during a reaction.

Most of the fuels used today are obtained from crude oil.

Which statement about crude oil is correct?

Crude oil is separated into several fractions by fractional distillation. Two of these fractions are kerosene and diesel oil.

State a use for each of these fractions.

kerosene_........

diesel oil_........

Figure 8 shows where the fractions kerosene and diesel oil are produced in the fractionating column.

Kerosene is obtained higher up the column than diesel oil. Kerosene and diesel oil fractions have slightly different properties.

Choose a property. State how this property for kerosene compares with the property for diesel oil.

property_........

comparison_........

Figure 9 shows the formulae of a molecule of butane and of a molecule of pentane. Butane and pentane are neighbouring members of the same homologous series.

Explain, using these formulae, why butane and pentane are neighbouring members of the same homologous series.

Butane has the formula C₄H₁₀.

Calculate the mass of carbon in 100 g of butane.

Give your answer to three significant figures.

(relative atomic masses: H = 1.00, C = 12.0; relative formula mass: C₄H₁₀ = 58.0)

You must show your working.

mass of carbon =_........ g

Butane burns completely in air to form carbon dioxide and water.

Write the word equation for this reaction.

An aluminium atom has the atomic number 13 and the mass number 27.

Which row shows the numbers of subatomic particles present in an

Magnesium burns in excess oxygen to form magnesium oxide. The balanced equation for this reaction is

Starting with 1.35 g of magnesium, calculate the maximum mass of magnesium oxide that could be formed in this reaction. (relative atomic masses: O = 16.0, Mg = 24.0)

You must show your working.

mass of magnesium oxide =_........ g

Chlorine reacts with hydrogen to form hydrogen chloride.

Write the balanced equation for this reaction.

*(d) Sodium chloride is an ionic compound, containing sodium ions, Na⁺, and chloride ions, Cl^–.

Figure 10 shows the electronic configuration of sodium and chlorine.

Explain how sodium and chlorine atoms form the ions in sodium chloride and how the ions are arranged in the solid sodium chloride.

You may wish to use diagrams in your answer.