+++++ Energy In Chemical Reactions

Question 1

What is an exothermic reaction

Answer 1

An exothermic reaction is one that gives out heat

Question 2

What is observed in an exothermic reaction

Answer 2

A temperature rise is observed when an exothermic reaction takes place

Question 3

Example of an exothermic reaction

Answer 3

The burning of coal or natural gas

Question 4

What is an endothermic reaction

Answer 4

An endothermic reaction is one that takes in heat

Question 5

What is observed in an endothermic reaction

Answer 5

A temperature drop

Question 6

Example of an endothermic reaction

Answer 6

Reaction of sherbet with water or photosynthesis

Question 7

What happens during photosynthesis

Answer 7

Plants take in energy from the sun and cause carbon dioxide and water to change into glucose and oxygen

Question 8

what is more common

Exo or endothermic

Answer 8

Exothermic

Question 9

What is an effective collision

Answer 9

It is one that results in the formation of products

Question 10

What is the collision theory

Answer 10

theoryused to predict the rates of chemical reactions, particularly for gases

Question 11

For a reaction to occur, what must happen

Answer 11

The reacting particles must collide with each other

Question 12

What is activation energy

Answer 12

It is the minimum energy that colliding particles must have for a reaction to occur, that is, the minimum energy required for effective collisions between particles to take place

Question 13

How do we explain why reactions are faster at higher temperatures

Answer 13

There is an increased number of collisions since the molecules have more energy.
More of the collisions have enough energy for the reaction to occur.

Question 14

What is the diagram used to show an exothermic or endothermic reaction

Answer 14

An energy profile diagram or a reaction profile diagram

Question 15

What is an energy profile diagram

Answer 15

It is a graph that shows the change in energy of a chemical reaction with time as the reaction takes place

Question 16

Do exothermic reactions products have more or less energy than the reactants

Answer 16

They have less energy than the reactants

Question 17

Do endothermic reactions products have more or less energy than the reactants

Answer 17

They have more energy than the reactants

Question 18

How is the energy given out represented by

Answer 18

Delta H

Question 19

Why does particle size affect the rate of reaction

Answer 19

The smaller the particle the more surface area is exposed causing more collisions
The number of collisions that are effective will increase because of this

Question 20

How does the concentration affect the rate of reaction

Answer 20

The molecules are crowded closer together. Therefore there number of effective collisions will increase
The rate of reaction will also increase

Question 21

Why do catalysts affect the rate of reaction

Answer 21

A catalyst works by providing an alternative route for the reaction to occur