Edexcel GCSE Combined Science Paper 4: Chemistry 2 Foundation June 2023 question paper 1SC0/2CF

Figure 1 shows the structure of a molecule of each of four compounds, A, B, C and D.

The formula of a molecule of compound A is H₂O.

Give the formula of a molecule of compound D.

The names of two of the compounds in Figure 1 are shown below.

Draw one straight line from each name to the structure of a molecule of that compound.

Figure 2 shows information about the number of electrons in the outer shell of each of the different atoms in a molecule of compound C.

Use the information in Figure 2 to complete the dot and cross diagram for a molecule of compound C.

The atomic number of phosphorus, P, is 15.

One atom of phosphorus has a relative atomic mass of 31.

Give the number of protons, neutrons and electrons in this atom of phosphorus.

number of protons =_........

number of neutrons =_........

number of electrons =_........

For steps 2 and 3, the student obtained the mass measurements shown in Figure 4 for the first salt.

Use the mass measurements in Figure 4 to calculate the mass of salt, in grams, added to the water.

mass of salt =_........ g

The student repeated the method for three different salts, A, B and C.

The same mass of each salt was used.

Figure 5 shows the temperature readings obtained for the three different salts.

Calculate the temperature change for salt C.

Include a sign to show if the temperature change is an increase or a decrease.

temperature change =_........ °C

Explain which salt produces the biggest exothermic change.

Explain why a polystyrene cup is a better container to use for this investigation than a glass beaker.

A scientist produced the information in Figure 6 about the Earth’s atmosphere and the Earth’s average surface temperature.

Use words from the box to complete the following sentence.

Over the past 3 billion years the average surface temperature of the Earth

The Earth’s atmosphere 3 billion years ago contained much more water vapour than today’s atmosphere.

Explain what happened to the water vapour.

Scientists think that the decrease in percentage of carbon dioxide was partly due to this gas being used in the growth of primitive plants.

Carbon dioxide was used in the growth of primitive plants and produced oxygen.

Give the name of the process in plants that takes in carbon dioxide and produces oxygen.

Which of the following tests would show that a gas is oxygen?

Many people are concerned by the increasing amount of carbon dioxide in the atmosphere.

The amount of carbon dioxide in the atmosphere is measured in parts per million (ppm).

Figure 7 shows the amount of carbon dioxide in the atmosphere in June 2001 and in June 2021.

Calculate the increase in the amount of carbon dioxide, in ppm, from June 2001 to June 2021.

Give your answer to the nearest whole number.

increase in amount of carbon dioxide =_........ ppm

State one possible effect that could be caused by the increasing amount of carbon dioxide in the atmosphere.

Chlorine is an element in group 7 of the periodic table.

What name is given to group 7 of the periodic table?

Chlorine reacts with sodium to form sodium chloride.

Write the word equation for this reaction.

Chlorine, Cl₂, is made of simple molecules.

Describe what is meant by the term molecule.

Sodium, like all metals, conducts electricity.

Explain how sodium conducts electricity.

Sodium chloride contains sodium ions, Na⁺, and chloride ions, Cl^–.

Use this information to state the formula of sodium chloride.

Sodium chloride is made of a giant structure of ions.

Which diagram shows the arrangement of particles in sodium chloride?

Sodium chloride solution conducts electricity.

State what can be put into the circuit in Figure 8 to show that a current is flowing.

Figure 9 shows a flow diagram of how hydrochloric acid can be made.

Balance the equation for the reaction between hydrogen and chlorine to form hydrogen chloride.

H₂ + Cl_{2 ........} HCl

State how hydrogen chloride can be converted into hydrochloric acid.

A student used the apparatus shown in Figure 10 to investigate the reaction between marble chips and dilute hydrochloric acid.

The student recorded the volume of gas every minute as shown in Figure 11.

On the grid, plot the results shown in Figure 11.

Draw a curve of best fit.

Rate of reaction can be calculated using

Figure 12 shows the rates of reaction calculated from the results of this experiment.

The rate of reaction for the time interval 2 to 3 minutes is missing.

Calculate the rate of reaction for the time interval 2 to 3 minutes.

rate of reaction =_........ cm³min^–1

State and explain what happens to the rate of reaction as the acid reacts with the marble chips in this experiment.

The student repeated the experiment using the same volume of acid and the same mass of marble chips but used smaller marble chips.

All other conditions remained the same.

The student found that the reaction with the smaller marble chips was faster to start with but produced the same volume of gas.

Using this information, draw a line on the grid to show the results for the reaction with the smaller marble chips.

Label this line ‘C’.

Which of the following changes would make the reaction faster?

State what could be used to measure time in the investigation.

Figure 13 shows some information about some group 1 metals.

Explain, in terms of their electronic configurations, why these metals are placed in group 1 of the periodic table.

Which row shows two correct properties of group 1 metals?

The word equation for the reaction of potassium with bromine is

potassium + bromine potassium bromide

Add the missing state symbol and balance the equation for this reaction.

_........ K(_........ ) + Br₂(g) _........ KBr(s)

A sample of potassium contains three isotopes, potassium-39, potassium-40 and potassium-41.

Explain the meaning of the term isotopes.

*(e) The reactivity of the group 1 metals increases from lithium to caesium.

Often, teachers demonstrate the reactions of lithium, sodium and potassium with water.

These reactions can be used to predict the behaviour and reactions of rubidium and caesium with water.

Describe the reactions of each of the group 1 metals with water including the predicted behaviour and reactions of rubidium and caesium.

You may use word equations in your answer.