Chemistry Topic 2

Question 1

Classify reaction as one of 5 types (with correct names)

Answer 1

CoDeS 1D2D

Single displacement 
Double displacement
Combustion
Synthesis
Decomposition

Question 2

Collision theory: How do chemical reactions happen?

Answer 2

In order for a reaction to occur, atoms and molecules must collide with each other.

Question 3

What are the three conditions for chemical reactions to occur?

Answer 3

Particles must collide
Reactants must have the activation energy to react
Particles must collide in the correct orientation in order to react (steric effect).

Question 4

What is the difference between temperature and heat?

Answer 4

The heat of an object is the total energy of all the molecular motion inside that object. Temperature is a measure of the average heat or thermal energy of the molecules in a substance.

Question 5

What is reaction rate and how can we calculate it?

Answer 5

The rate of reaction is the change of concentration over time. It can be measured by the gradient of the slope.

Question 6

What are the factors that can alter the reaction rate?

Answer 6

Amount of reactant used- More particles in the same area
Temperature- Particles move around with more energy/speed
Surface area- Increases the amount of opportunities for more collisions
Is a catalyst used or not?- More particles will have enough energy to react, which means more reactions.

Question 7

What is an endothermic reaction?

Answer 7

When energy in the system is lower at the end than the start, so there is a release of energy (usually as heat).

Question 8

What is an exothermic reaction?

Answer 8

When energy in the system is higher at the end than the start, so energy has been absorbed.

Question 9

How does temperature affect endothermic and exothermic reactions?

Answer 9

If the temperature is increased the amount of product is increased.