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1

Define the law of conservation of matter.

Matter can be neither created nor destroyed. The atoms are simply just rearranged to create new substances.

2

Define endothermic.

A reaction that absorbs heat, taking it from the surroundings and making it feel colder. The products have more energy than the reactants.

3

Define exothermic.

A reaction that releases energy. The reactants have more energy than the products.

4

Is photosynthesis endo or exothermic?

Endothermic.

5

Is respiration endo or exothermic?

Exothermic.

6

Define combustion.

Types of exothermic reactions that require a fuel and an oxygen.

7

Define complete combustion and provide an example.

A type of combustion that occurs only if sufficient oxygen is present, the products always being carbon dioxide and water. e.g. octane + oxygen gas -> carbon dioxide + water.

8

Define an incomplete combustion and provide an example.

A type of combustion that occurs when insufficient oxygen is present, the products always being carbon monoxide/water, and carbon. e.g. methane + oxygen gas -> water + carbon

9

What is the general equation of combustion?

fuel + oxygen gas -> carbon dioxide + water + energy

10

Define a corrosion reaction.

A type of reaction that requires oxygen and involves metals corroding

11

Define acids

substances that release hydrogen ions (H+) into aqueous solutions (e.g. hydrochloric acid in your stomach)

12

Define bases.

substances that release hydroxide ions (OH+). E.g. ammonia

13

What are the 6 properties of acids?

- corrosive
- turns blue litmus paper red
- have a sour taste
- conduct electricity
- are neautralised by bases
- react with some metals, releasing hydrogen gas and leaving salt behind.

14

What are the 6 properties of bases?

- caustic
- have a soapy, slimy feel
- have a bitter taste
- conduct electricity
- Turn red litmus paper blue
- are neutralised by acids, producing water and salt.

15

Define alkalis.

Bases that are soluble in water.

16

What is the pH scale;

A scale that measures how acidic or basic a substance is, with numbers ranging from 1-14.

17

Where does an acid fall on the pH scale?

any pH less than 7.

18

Where does a base fall on the pH scale?

any pH greater than 7

19

Define a neutral substance.

It is neither acidic nor basic, it contains the same amount of hydrogen and hydroxide ions. It falls on 7 in the pH scale.

20

What is the general reaction for neutralisation?

acid + base -> salt + water

21

What is the general reaction for acids and metals?

acid + metal -> salt + hydrogen gas

22

What is the general reaction for acids and carbonates?

acid + carbonate -> salt + water + carbon dioxide

23

What is the general reaction for acids and digestion?

hydrochloric acid + sodium hydrogen carbonate -> sodium chloride + water + carbon dioxide

24

What is a process in digestion that allows food to be digested?

Saliva in your mouth is slightly basic, so it helps to neautralise some of the acids that you eat like orange juice.