Gases in the Atmosphere

7 marks · Normal

This question is about the reactions and environmental impact of oxides and carbon dioxide.

(a)

Describe what happens when copper(II) carbonate is heated strongly in a test tube, include the name and properties (acidic or basic) of the solid product.

[3 marks]

(b)

Write a balanced chemical equation for the thermal decomposition of copper(II) carbonate.

[1 mark]

(c)

Explain how the carbon dioxide gas formed from this reaction can contribute to global warming.

[3 marks]

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

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(a) When copper(II) carbonate is heated, it decomposes to form a black solid, copper(II) oxide (a basic oxide), and releases carbon dioxide gas. · must show Describes decomposition to copper(II) oxide and CO2, States the colour change (green to black), Identifies copper(II) oxide as a basic oxide

(b) · must show Correct balanced equation with state symbols

(c) Carbon dioxide is a greenhouse gas. When released, it absorbs infrared radiation from the Earth's surface, re-emits it in all directions, and warms the atmosphere, contributing to global warming. · must show States CO2 is a greenhouse gas, Mentions absorption of infrared radiation, Explains warming of atmosphere/global warming

Common mistakes: Omitting the colour change for copper(II) oxide; Not stating copper(II) oxide is basic; Incorrectly linking carbon dioxide to acid rain instead of greenhouse effect

Show mark scheme and worked solution

Marking points

B1 (a) · 1 mark · Describes thermal decomposition of copper(II) carbonate to copper(II) oxide and CO2

B2 (a) · 1 mark · Mentions solid turns black (green to black)

B3 (a) · 1 mark · Identifies copper(II) oxide as a basic oxide

B4 (b) · 1 mark · Correct balanced equation with state symbols

B5 (c) · 1 mark · States carbon dioxide is a greenhouse gas

B6 (c) · 1 mark · Mentions that CO2 absorbs infrared radiation

B7 (c) · 1 mark · Explains that this causes warming of the atmosphere/global warming

Worked solution

a) Upon heating, copper(II) carbonate decomposes to produce copper(II) oxide and carbon dioxide gas. The solid changes from green to black, as copper(II) oxide forms. Copper(II) oxide is a basic oxide.

c) Carbon dioxide released in this reaction is a greenhouse gas. As CO2 builds up in the atmosphere, it absorbs IR radiation from the Earth's surface and re-emits it, which leads to warming of the atmosphere (global warming effect).