Y10 Spring Term Chemistry Round Up

Question 1

What is an exothermic reaction?

Answer 1

A reaction where more energy comes out than in. In an exothermic reaction the reactants have more energy than the products

Question 2

What’s an endothermic reaction?

Answer 2

A reaction where more energy comes in than out. In a endothermic reaction the products have more energy than the reactants

Question 3

Give an example of an exothermic reaction

Answer 3

Combustion, oxidation, neutralisation etc.

Question 4

Give an example of a endothermic reaction

Answer 4

Thermal decomposition

Question 5

What’s an example of an everyday use of an exothermic reaction and how does it do this?

Answer 5

Self-heating cans, hand warmers etc. They give out heat energy to the surroundings

Question 6

What’s a example of an everyday use of a endothermic reaction and how does it do this?

Answer 6

Cool packs for sports injuries. Chemicals take in heat energy and cool the surroundings

Question 7

What’s the reaction profile for an exothermic reaction?

Answer 7

Products are at a lower energy level than reactants

Question 8

What’s the reaction profile for a endothermic reaction?

Answer 8

Products are at a higher energy level than reactants

Question 9

What is activation energy?

Answer 9

The energy needed to start a reaction

Question 10

What does the acronym BINMIX stand for?

Answer 10

(Bond) Breaking
Is
eNdothermic
(Bond) Making
Is
eXothermic

Question 11

How does bond energy work in exothermic reactions?

Answer 11

More energy comes out making bonds

Question 12

How does bond energy work in endothermic reactions?

Answer 12

More energy comes in breaking bonds

Question 13

What is a pure substance?

Answer 13

A single element/compound that isn’t mixed with any other substance

Question 14

What is formulation?

Answer 14

A mixture that has been designed as a useful product

Question 15

What is chromatography?

Answer 15

A technique that can be used to separate mixtures and identify the substances

Question 16

How do you test for carbon dioxide gas?

Answer 16

It turns limewater cloudy/milky

Question 17

How do you test for hydrogen gas?

Answer 17

Bringing a lit splint into the presence of hydrogen gas causes it to make a squeaky pop sound

Question 18

How do you test for oxygen gas?

Answer 18

You hold a glowing splint at the open end of a test tube If the glowing splint relights then the test tube contains oxygen

Question 19

How do you test for chlorine gas?

Answer 19

To test for chlorine, you use damp litmus paper. When chlorine gas is present the gas bleaches the paper white

Question 20

What was Earth’s early atmosphere like?

Answer 20

It is unclear what Earth’s early atmosphere was like. However most scientists agree that Earth’s atmosphere most likely contained carbon dioxide, nitrogen, methane and ammonia

Question 21

What caused the makeup of Earth’s early atmosphere?

Answer 21

Heavy volcanic activity

Question 22

How were oceans formed?

Answer 22

From condensed water. Carbon dioxide dissolved in the oceans, carbonates precipitated (turned into solid bits) to form sediments

Question 23

How were plants/algae formed?

Answer 23

Took in carbon dioxide and released oxygen in photosynthesis.

Question 24

How were sedimentary rocks/fossil fuels formed?

Answer 24

Decreased carbon dioxide levels

Question 25

What are the greenhouse gases?

Answer 25

- Carbon dioxide - Methane - Water Vapour

Question 26

What are the stages of the Greenhouse Effect?

Answer 26

1) Some short-wavelength radiation (ultraviolet) passes straight through the atmosphere and is reflected, without heating it up. This radiation doesn’t interact with the gases in the atmosphere 2) Most radiation is absorbed by Earth’s surface and warms it 3) The Earth’s surface re-emits energy as longer wavelength infrared radiation that interacts with the gases in the atmosphere 4) Some of the infrared radiation is absorbed by greenhouse gas molecules. This warms up the Earth’s surface and the atmosphere

Question 27

What causes climate change?

Answer 27

Human activities increase the levels of carbon dioxide and methane

Question 28

What human activities contribute to climate change?

Answer 28

CO2: - Burning fossil fuels - Deforestation Methane: - Cow farming (and rice paddies) - Landfill sites

Question 29

What are the effects of climate change?

Answer 29

- Rising sea levels - Droughts - Extreme weather events - Changes in wildlife distribution

Question 30

Why do some people deny that humans contribute to climate change?

Answer 30

- Difficult to model - Models are simplified - The media can be biased - Must check that the evidence is peer reviewed

Question 31

What is a “carbon footprint”?

Answer 31

The total amount of CO2 and other greenhouse gases emitted over the full life cycle of a product, service or event

Question 32

What are some solutions to combat climate change?

Answer 32

- Reduce carbon footprint - Use less fossil fuels - Carbon capture and storage - Eat less meat - Send less food waste to landfill

Question 33

What are the gases released in the combustion of fossil fuels and how do they effect the planet?

Answer 33

Carbon dioxide: - Released when all fossil fuels burn - Causes global warming Water Vapour: - Released when all fossil fuels burn - Has no harmful consequences Carbon monoxide: - Released by incomplete combustion of fossil fuels (not enough O2) - Causes a poisonous gas deadly to humans Solid particulates: - Released when solid fuels burn incompletely - Causes global dimming and asthma Sulphur dioxide: - Released when coal burns - Causes acid rain and respiratory problems Nitrous oxides: - Released when nitrogen in the air reacts with oxygen - Causes acid rain and respiratory problems