Chemical Reactions

Question 1

What are the 5 main types of chemical reactions?

Answer 1

Synthesis
Decomposition
Combustion
Single replacement
Double replacement

Question 2

What is Combustion?

Answer 2

Combustion describes any chemical reactions in which a reactant burns in oxygen (from the air) to produce heat (and light).

Question 3

Does Combustion occur quickly?

Answer 3

Combustion reactions occur quickly

Question 4

What type of reaction is Combustion?

Answer 4

This is an exothermic reaction.

Question 5

What are the two types of Combustion?

Answer 5

Incomplete and complete combustion

Question 6

Synthesis is?

Answer 6

Combination / Synthesis reactions occur when 2 reactants form 1 product.

Question 7

What is complete combustion？

Answer 7

Fuels such as natural gas and petrol contain hydrocarbons. These are compounds of hydrogen and carbon only. When they burn completely:
The carbon oxidises to carbon dioxide.
The hydrogen oxidises to water

Question 8

What is incomplete combustion？

Answer 8

Incomplete combustion occurs when the supply of air or oxygen is poor, which stops the fuel from burning completely.
Water is still produced, but carbon monoxide and carbon are produced instead of carbon dioxide.

Question 9

What is the other name for combination reactions?

Answer 9

Synthesis reactions

Question 10

What is single replacement?

Answer 10

The removal of one element or group of elements and replacing them with another element of group of elements.

For instance:

Copper + Silver Nitrate → Silver + Copper Nitrate

Question 11

What is double replacement?

Answer 11

These reactions involve two compounds reacting and swapping ions to form two new compounds.
- metals swap
For instance:
Potassium Iodide + Lead Nitrate
→ Potassium Nitrate + Lead Iodide

Question 12

What is the other name for double replacement?

Answer 12

Double replacement or precipitation

Question 13

What is Decomposition?

Answer 13

When a single reactant breaks apart to form several products, the reactant is said to decompose.

Question 14

What is a chemical reaction?

Answer 14

The processes by which chemicals interact to form new chemicals with different compositions. AKA In a chemical reaction new products are formed.

For instance:
When a piece of sodium is put into water, it fizzes about and a gas is formed.

Question 15

What does an Acid + base make?

Answer 15

water + salt

Question 16

What does an Acid + Metal make?

Answer 16

Salt + Hydrogen Gas

Question 17

Acid + Carbonate = ???

Answer 17

Salt + Water + Carbon dioxide

Question 18

What is a precipitate?

Answer 18

2 soluble reactants combine to form an insoluble product called a precipitate.

The precipitate may make the solution look murky if the solid is very fine or will settle to the bottom of the container as a sediment, if the solid is denser.

The precipitate is often a different colour to the reactants.

Question 19

What is the Law of Conversation of Mass?

Answer 19

The law of conservation of mass states that mass cannot be created nor destroyed during a chemical reaction, it can only be transferred or transformed. Therefore, the number of atoms on both sides of the equation must be equal.

Question 20

A + B –》ab

WHICH IS THE REACTANT?

Answer 20

A + B BECAUSE IT IS BECOMING SOMETHING ELSE. ALSO BECAUSE ITS SHOOTING AN ARROW !!!

Question 21

What are exothermic reactions?

Answer 21

When these reactions occur, the amount of energy stored in the reactants is greater than that stored in the products.

As a result, energy is released and we call the reaction exothermic.

The energy released takes the form of light or heat.

Question 22

Endothermic

Answer 22

When the products have more energy than the reactants, energy in the form of heat/light is absorbed, leaving the surrounding area colder.

Question 23

Does heat exit in an exothermic reaction?

Answer 23

EXO like EXIT!
It releases heat, causing the temperature of the immediate surroundings to rise

Question 24

Examples of Exothermic reactions

Answer 24

Burning of candles - heat is being released.
Freezing of water into ice - heat is being released that it freezes.
Rusting of iron

Question 25

Examples of endothermic reactions

Answer 25

Melting ice cubes - Cuz heat is being ABSORBED Photosynthesis Chemical cold packs

Question 26

What is particle theory?

Answer 26

Particles are constantly moving, some with more energy than others. For a chemical reaction to take place between two reactants, their particles must collide first. For the collision to be effective, (meaning, for a reaction to occur), the particles must have the right amount of energy. The minimum amount of energy required for an effective collision is called the activation energy.

Question 27

What factors can influence The Rate of Reaction?

Answer 27

Agitation, Surface Area, Temperature, Catalyst, Concentration

Question 28

Temperature affects the rate of reaction by？

Answer 28

Increasing temperature increases the rate of reaction. Particles have more energy, which means that they collide more frequently, which allows for new products to be formed. Moreover, they will be able to meet the demands of activation energy.

Question 29

Concentration affects the rate of reaction by？

Answer 29

Increasing the concentration of the reactants means that more particles are available to react. Hence, particles are more likely to collide and rearrange to form new products.

Question 30

Agitation affects the rate of reaction by？

Answer 30

Agitation or stirring the solution ensures the reactants are kept in contact. This will prevent clumps or sediment being formed, which might otherwise reduce the rate of reaction. Magnetic stirrers can be used in the laboratory to create agitation:

Question 31

Catalyst affects the rate of reaction by？

Answer 31

Catalysts are chemicals that speed up chemical reactions but are not used up in the reaction. They do this by either: reducing the amount of energy required to convert the reactants into products providing an alternative pathway for reactants to combine to form new products

Question 32

Surface Area affects the rate of reaction by？

Answer 32

By cutting up or crushing solid reactants into smaller pieces, the reactants will have more surface area. If the surface area of a reactant is increased, more particles are exposed to the other reactant. This creates a greater chance of particles colliding, which leads to more successful collisions per second - increasing the rate of reaction.

Question 33

Why are chemical reactions important?

Answer 33

Chemical reactions are important as the allow living beings to grow, develop reproduce and adapt. Photosynthesis is a chemical reaction and without it most plants would die. Moreover, chemical reactions are vital in the production of many consumer products such as alcohol which uses yeast and fermentation. Whereas chemical reactions are slowed down to preserve and and extend the lifespan of buildings and structures.