ENDO & EXO Thermic

Question 1

Exothermic means?

Answer 1

Heat is given out

Question 2

What transfer of energy happens during an exothermic reaction?

Answer 2

Energy is tranferred to the surroundings and the temperature of the surroundings increases.

Question 3

Endothermic means?

Answer 3

Heat is taken in

Question 4

What happens to energy during endothermic reactions?

Answer 4

Energy and the temperature of the surroundings decreases.

Question 5

Combustion reactions are classed as endothermic or exothermic?

Answer 5

Exothermic

Question 6

Many oxidation reactions are classed as endothermic or exothermic?

Answer 6

Exothermic

Question 7

Hand warmers would be classed as endothermic or exothermic?

Answer 7

Exothermic

Question 8

Thermal decomposition is classed as endothermic or exothermic?

Answer 8

Endothermic

Question 9

Ice packs are classed as endothermic or exothermic?

Answer 9

Endothermic

Question 10

What are the 3 requirements of the fire triange?

Answer 10

Heat

Oxygen

Fuel

Question 11

In the endothermic process, bonds are?

Answer 11

Broken

Question 12

In the exothermic process, bonds are?

Answer 12

Formed

Question 13

What piece of apparatus is used to measure temperature changes?

Answer 13

Thermometer

Question 14

What term is given to a reaction which transfers heat energy to the surroundings?

Answer 14

Exothermic

Question 15

When barium hydroxide and ammonium chloride react, the temperature of the mixture decreases. What kind of reaction is this?

Answer 15

Endothermic

Question 16

Which of the following should be used to contain the solution when investigating an energy change?

• A polystyrene cup
• A glass beaker
• A measuring cylinder

Answer 16

A polystyrene cup

A polystyrene cup should be used because it insulates the contents from losing or gaining heat from the surroundings. A measuring cylinder is useful for measuring the volumes of liquids.

Question 17

If the energy change on an energy level diagram is negative, what does this tell you about the reaction?

Answer 17

It is exothermic

Exothermic reactions have a negative energy change on an energy level diagram. Endothermic changes have a positive energy change.

Question 18

On a reaction profile, what does the height of the hump represent?

Answer 18

The activation energy

Question 19

Which of these is an endothermic reaction?

• Combustion
• Thermal decomposition
• Oxidation of magnesium

Answer 19

Thermal decomposition

Question 20

What can you deduce from the reaction profile below?

• The reaction is endothermic
• A catalyst is present
• More energy is released than absorbed

Answer 20

The reaction is endothermic

This reaction profile shows an endothermic reaction. In an endothermic reaction, more heat is absorbed than released.

Question 21

When calcium reacts with water, the temperature changes from 18°C to 39°C. Is this endothermic or exothermic?

Answer 21

Exothermic

Question 22

If a reaction releases more energy when new bonds are made than the amount of energy absorbed to break bonds in the reactants, which statement is true? - Higher

• It is endothermic
• It is exothermic
• It is very slow

Answer 22

It is Exothermic

An exothermic reaction releases more energy when new bonds are made than the amount of energy which was absorbed to break the bonds in the reactants.