MT2

Question 1

How can chemical reactions be identified?

Answer 1

Energy changes

Question 2

What are the two energy changes?

Answer 2

Exothermic reaction & Endothermic reaction

Question 3

What is an exothermic reaction?

Answer 3

An exothermic reaction RELEASES energy to their surroundings, the temperature will INCREASE and the PRODUCTS will have LESS chemical energy than the REACTANTS.

Question 4

What is an endothermic reaction?

Answer 4

An endothermic reaction ABSORBS energy, causing the temperature to DROP. The products (of the reaction) will have MORE chemical energy than the reactants.

Question 5

What are reactants in a word equation?

Answer 5

The substances that react together

Question 6

What are the products in a word equation?

Answer 6

The substances formed

Question 7

What are the state symbols in a word equation?

Answer 7

Solid = (s)
Liquid = (l)
Gas = (g)
Aqueous solution = (aq) (means dissolved in pani)

Question 8

What is a fuel?

Answer 8

A substance that BURNS in OXYGEN to release ENERGY

Question 9

What is the composition of air?

Answer 9

Nitrogen (79%) Oxygen (19%) Carbon Dioxide (0.04%) Argon (1.96%)

Question 10

What is combustion?

Answer 10

Combustion is another name for a chemical reaction of a fuel burning (in oxygen)

Question 11

What does it mean when a substance burns?

Answer 11

Reacts with oxygen

Question 12

What is the test for oxygen?

Answer 12

Oxygen relights a glowing splint.

Question 13

When carbon burns in oxygen, what does it produce?

Answer 13

Carbon dioxide (CO₂). Or Carbon monoxide, if INCOMPLETE COMBUSTION takes place.

Question 14

What is the test for carbon dioxide?

Answer 14

Carbon dioxide turns lime water cloudy.

Question 15

What is incomplete combustion?

Answer 15

When a lack of oxygen is produced.

Question 16

What is produced as a result of incomplete combustion?

Answer 16

Carbon monoxide.

Question 17

What is the word equation for carbon dioxide?

Answer 17

carbon + oxygen → carbon dioxide

Question 18

What is the test for hydrogen?

Answer 18

Hydrogen burns with a squeaky pop.

Question 19

What is the word equation for water?

Answer 19

hydrogen + oxygen → hydrogen oxide (water)

Question 20

What are the three fossil fuels?

Answer 20

Crude oil, natural gas and coal

Question 21

When were fossil fuels formed?

Answer 21

Millions of years ago.

Question 22

How are crude oil and natural gas made?

Answer 22

They were made MILLIONS OF YEARS AGO when DEAD CREATURES UNDER THE SEA BED are exposed to HEAT and PRESSURE. Natural gas can also be found next to it.

Question 23

How is coal made?

Answer 23

Coal is made when trees/plants millions of years ago were exposed to HEAT and PRESSURE, causing them to change chemically.

Question 24

What are hydrocarbons?

Answer 24

Hydrocarbons are compounds that only contain hydrogen and carbon.

Question 25

What is the word equation for burning a hydrocarbon?

Answer 25

hydrocarbon + oxygen → water + carbon dioxide

Question 26

How can we prove that water + carbon dioxide is produced from burning a hydrocarbon?

Answer 26

Lime water turned cloudy which indicates carbon dioxide is present Water vapour condensed at 100°C

Question 27

What does it mean when fossil fuels are FINITE?

Answer 27

It means that they run out. Another way to say this is that they are NON-RENEWABLE.

Question 28

What is hydrogen being hailed as?

Answer 28

A fuel of the future because it is inexpensive and can be extracted from water. It is also the most abundant element in the universe

Question 29

A REACTION IS ENDOTHERMIC IF… (CHOOSE ONE) A - energy is required to start the reaction B - heat is released during the reaction C - the temperature drops during the reaction D - the temperature rises during the reaction

Answer 29

C - the temperature drops during the reaction

Question 30

A REACTION IS EXOTHERMIC IF… (CHOOSE ONE) A - energy is absorbed from the surroundings B - energy is released to the surroundings C - energy is required to start the reaction D - there is no energy change

Answer 30

B - energy is released to the surroundings

Question 31

What do crude oil and natural gas mainly consist of?

Answer 31

Hydrocarbons.

Question 32

What are the 3 things required for burning?

Answer 32

Oxygen, heat energy, fuel

Question 33

What are fossil fuels?

Answer 33

Fossil fuels are fuels that contain hydrocarbons, are finite and are made from plants, trees and animal remains millions of years ago.