Energy changes

Question 1

What is a exothermic reaction?

Answer 1

When energy is transferred to the surrounding area.

Question 2

What is a endothermic reaction?

Answer 2

When energy is drawn from the surrounding area.

Question 3

What is a reaction profile?

Answer 3

Shows whether a reaction is exothermic or endothermic.

Question 4

What is activation energy?

Answer 4

The activation energy is the minimum ammount of energy that particles must have to react when they collide.

Question 5

What energy is produced when a bond is broken?

Answer 5

endothermic

Question 6

What energy is produced when a bond is made?

Answer 6

exothermic

Question 7

How is a chemical cell used in batteries?

Answer 7

A battery is formed of two or more chemical cells connected in series.

Question 8

What is a chemical cell?

Answer 8

In a metal displacement reaction, one metal is oxidised - it loses electrons. THese electrons are transferred to another metal, which gains the electrons so is reduced.

Question 9

What are hydrogen fuel cells?

Answer 9

Hydrogen fuel cells generate electricity by reacting hydrogen and oxygen. 2H² + O² –> 2H²O

Question 10

What are the advantages of hydrogen fuel cells?

Answer 10

• The only waste is water
• Do not need to be electrically recharged

Question 11

What are the disadvantages of hydrogen fuel cells?

Answer 11

• Hydrogen is highly flammable and difficult to store
• Hydrogen is often produced from non-renewable resources