Earth & Atmospheric Science (Edexcel GCSE Chemistry: Combined Science)

The Earth's atmosphere has evolved over the past 4.6 billion years. 

Which option correctly shows what has happened to the proportion of each gas during this time period?

This question is about changes to the Earth’s atmosphere.

Several processes change the composition of the Earth’s atmosphere.

Describe how the composition of the atmosphere is affected by burning fossil fuels.

The graphs in Figure 1 and Figure 2 show the concentration of carbon dioxide in the atmosphere and the mean global temperature between 1960 and 2000.

Explain whether these graphs provide evidence that an increase in carbon dioxide is causing the Earth’s temperature to rise.

Which of these pairs of gases are both greenhouse gases?

What is the approximate percentage of oxygen in the current atmosphere? 

The Earth’s atmosphere contains several gases.

Figure 1 shows the relative amounts of gases thought to be in the Earth’s early atmosphere.

Figure 1

The amount of water vapour in today’s atmosphere is much less than the amount in the Earth’s early atmosphere.
Explain why the amount of water vapour in the atmosphere has decreased.

The apparatus shown in Figure 2 is used to find the percentage of oxygen in dry air.

Figure 2

Syringe A contains 50 cm³ of dry air and syringe B contains no air.

The copper in the glass tube is heated strongly.
The air in the apparatus is passed backwards and forwards over the copper until
all the oxygen has been removed.

The Earth’s earliest rocks contained iron sulfide and no iron oxide.
Later the rocks contained iron oxide as well as iron sulfide.

Explain what happened to allow this change to occur.

Global climate change has serious consequences on the environment. 

Which of the following shows an incorrect effect of global climate change?

The two most common gases in today’s atmosphere are nitrogen and oxygen.

(1)

(1)

Give the name of the most common gas in the Earth’s early atmosphere.

This early atmosphere was hot and contained water vapour.
The atmosphere today contains less water vapour.

Explain what caused the amount of water vapour in the atmosphere to decrease.

The concentration of carbon dioxide in the atmosphere can be measured in parts per million (ppm).
Figure 1 shows the measurements in January 2018 and January 2019.

Figure 1

increase in concentration of carbon dioxide = .............................. ppm

Human activities are contributing to the enhanced greenhouse effect. 

Which two human activities contribute to the release of methane?

Air contains several gaseous elements.

Which of these shows the three most common gaseous elements in air, listed in order from the most common to the least common?

The density of a gas can be found using the equation

A student carried out an experiment to find the density of argon.

The mass of a stopper and flask, containing no gas, was known.
The flask was completely filled with argon and its mass measured.

Figure 4 shows the results the student wrote down.

Figure 4

density of argon = ........................................... gcm^-3

Figure 5

There is an error in the volume the student has used in the calculation.
This would give an incorrect value for the density of argon.

Identify this error and state what should be done to correct it.

(2)

error.................................

what should be done to correct it ........................................

Four of the noble gases are argon, helium, krypton and neon.

Give these gases in order of increasing density.

Higher Only

Much of the carbon dioxide present in the Earth’s early atmosphere dissolved into the oceans.

This led to the formation of compounds including calcium carbonate, CaCO₃.

Some of the calcium carbonate reacted with magnesium ions to form dolomite, CaMg(CO₃)₂.

Complete the ionic equation for the reaction of calcium carbonate with magnesium ions.

................ CaCO₃ + ......................... → CaMg(CO₃)₂ + Ca²⁺
                                               dolomite

P and Q are both mixtures of gases.
One has the same composition as the early atmosphere and the other has the same composition as the current atmosphere.

Tests are carried out on gas mixtures P and Q.

The test for carbon dioxide is to bubble the gas into limewater; if carbon dioxide is present calcium carbonate is formed.

The results of the tests are shown in Figure 6.

Figure 6

Explain, using the data in Figure 6, which gas mixture represents the early atmosphere.

What is the correct observation when a glowing splint is held at the entrance of a tube of pure oxygen gas? 

Diesel oil is a mixture of hydrocarbons that can be obtained from crude oil.

State the name of the process used to separate diesel oil from crude oil.

Diesel oil contains alkanes.
These alkanes are part of an homologous series.

Which statement about compounds in this homologous series is true?

When fuels such as diesel oil are burned, the high temperatures produced can cause nitrogen and oxygen in the air to form the pollutant nitrogen dioxide.

Complete the balanced equation for the reaction.

Explain how the greenhouse effect is caused by the gases produced by the complete combustion of diesel oil.

Diesel oil can contain impurities of sulfur.
Burning diesel oil containing impurities of sulfur can result in acid rain.
Acid rain is harmful to the environment.

Explain how acid rain is formed and the harm it can do.

The greenhouse effect allows the Earth to stay warm enough to support life. 

Which statement describing the greenhouse effect is true?

This question is about potassium and zinc.

Which of the following temperatures is most likely to be the melting point of potassium?

Explain how the electronic configuration of an atom of potassium is related to its position in the periodic table.

Potassium reacts with oxygen to form potassium oxide.

(2)

(2)

potassium ion: ............................................
oxide ion: .............................................

Figure 6 shows two gas syringes connected by a glass tube.

Inside the glass tube there are some pieces of zinc.
Zinc reacts with oxygen at a temperature of over 225 °C.
Not all the oxygen reacts at once, the oxygen reacts only when in contact with the zinc.

Figure 6

Devise a plan to find the volume of oxygen contained in a known volume of air, using the apparatus shown in Figure 6.

Carbon dioxide is one of the gases in the Earth’s atmosphere.
The percentage of carbon dioxide in the Earth’s atmosphere has changed over time.

(1)

(4)

Carbon dioxide is a simple molecular, covalent compound.

It has a low boiling point of –78.5°C.

Explain why carbon dioxide has a low boiling point.

Calculate the number of molecules in 0.11 g of carbon dioxide.

Give your answer to two significant figures.

(relative formula mass : CO₂ = 44
Avogadro constant = 6.02 × 10²³)

This question is about the atmosphere of Mars.

The composition of its atmosphere is shown in the pie chart in Figure 1. 

Calculate the percentage of other gases on Mars.

It is thought when the Earth formed 4.5 billion years ago, the atmosphere was similar to that of Mars.

The growth of green plants and evolution of other organisms has changed the composition of the atmosphere over this period of time. 

Explain how.

Carbon dioxide is a greenhouse gas that contributes to global warming.

Suggest four effects of global climate change.

This question is about carbon dioxide.

Carbon dioxide gas levels have remained the same over the last 200 million years.

Complete the dot and cross diagram to show the bonding carbon dioxide gas in Figure 1. 

Figure 1

Explain why carbon dioxide is a gas at room temperature 

Describe the natural processes which remove carbon dioxide from the atmosphere. 

Explain why carbon dioxide levels have risen again over the last 150 years.

The atmosphere has evolved over the last 4.5 billion years. 

Explain why there is less water vapour in the atmosphere now, compared to 4.5 billion years ago. 

It is thought that the Earth's early atmosphere was similar to the atmosphere found on Venus today.

Table 1 shows the percentages of oxygen and carbon dioxide on each planet. 

Explain the processes that have led to the changes in oxygen and carbon dioxide levels on Earth.

Scientists cannot be certain about the proportion of gases that made up the early atmosphere of Earth.

Why not?

This question is about the atmosphere.

The planet Saturn has many moons, including one named Titan. 

Titan's atmosphere is warmer than other moons because it contains methane, a greenhouse gas. 

Explain how methane keeps Titan warmer than other moons.

In addition to methane, other gases are found in the atmosphere of Titan.

These gases and their percentages are shown in Table 1. 

Explain why life could not have evolved in the same way it is thought to have evolved on Earth. 

Higher Tier 

Methane can also be used as a fuel and undergo combustion to produce carbon dioxide and water.

The equation for this reaction can be shown as:

Table 1

Use the bond energies in Table 1 to calculate the energy change for the reaction. 

Explain, in terms of bond making and breaking, why this is an exothermic reaction.