C5 20 Questions

Question 1

What do we call reactions which transfer energy to the surroundings?

Answer 1

Exothermic

Question 2

A white powder dissolves in water to form a solution. The temperature falls by 2oC. State and explain the type of reaction that has taken place.

Answer 2

Endothermic – the temperature falls because energy is taken in from the surroundings.

Question 3

The sketch on the right shows a reaction profile.
Does it represent an exothermic or an endothermic reaction?

Answer 3

Endothermic

Question 4

If you calculate the overall change in bond energy for an exothermic reaction, would you expect it to be positive or negative?

Answer 4

Negative

Question 5

What property of metals makes them suitable for use as electrodes?

Answer 5

They conduct electricity

Question 6

What is activation energy?

Answer 6

The minimum energy required to start a reaction.

Question 7

A chemical reaction gives out more energy when new bonds are formed in the products than it takes in to break the bonds in the reactants. What sort of reaction is it?

Answer 7

Exothermic