Energy Changes

Question 1

Is the reaction between hydrogen and oxygen exothermic or endothermic?

Answer 1

exothermic

Question 2

Sodium hydroxide reacts with hydrochloric acid in a neutralisation reaction. Will the temperature of the solution increase or decrease during this reaction?

Answer 2

increase

Question 3

Sodium hydrogencarbonate (bicarbonate of soda) is added to a solution of citric acid. During the reaction, will the temperature go up or down?

Answer 3

it will go down

Question 4

5g of ammonium nitrate was dissolved in 60g of water in an insulated container. The temperature at the start of the reaction was 23.0°C and at the end it was 18.5°C. Was this an exothermic or an endothermic reaction?

Answer 4

endothermic

Question 5

Calcium carbonate can be broken down by heating. What is the scientific term for this?

Answer 5

thermal decomposition

Question 6

During an exothermic reaction, will the temperature of the reaction vessel increase, decrease or stay the same?

Answer 6

increase

Question 7

In a reversible, endothermic reaction, hydrated copper sulfate is converted to anhydrous copper sulfate and water. Would you expect the reverse reaction to give out or take in energy?

Answer 7

give out energy

Question 8

Which of the following is NOT an example of an exothermic reaction: Combustion, electrolysis, or neutralisation?

Answer 8

electrolysis

Question 9

A reaction has taken place, and as a result the mixture has warmed. What type of reaction has taken place?

Answer 9

exothermic

Question 10

During an _______________ reaction, the temperature increases.

Answer 10

exothermic

Question 11

During an exothermic reaction, the ______________ increases.

Answer 11

temperature

Question 12

During an exothermic reaction, the temperature __________.

Answer 12

increases

Question 13

True or false? Exothermic reactions do not have an activation energy.

Answer 13

false

Question 14

40 cm3 of acid were mixed with 60 cm3 of alkali in an insulated container. The average temperature of the two solutions before they were mixed was 19.5°C. The temperature after mixing was 27.5°C. Was this an exothermic or an endothermic reaction?

Answer 14

exothermic

Question 15

Professional sportspeople sometimes use special cooling packs as an alternative to ice packs after an injury. Are these packs based on an exothermic or an endothermic reaction?

Answer 15

endothermic

Question 16

What is a good insulator?

Answer 16

polystyrene

Question 17

Polystyrene is a good insulator, so it will prevent _____ ________ during the reaction.

Answer 17

heat transfer

Question 18

When magnesium is burned in air, large amounts of heat and light are given out. Is this an example of an exothermic or an endothermic reaction?

Answer 18

exothermic

Question 19

______________ is an exothermic reaction, so temperatures will increase.

Answer 19

neutralisation

Question 20

Neutralisation is an ____________ reaction, so the temperature would increase.

Answer 20

exothermic

Question 21

A sports injury pack that turns cold when activated is based on an __________ reaction.

Answer 21

endothermic

Question 22

________ ________________ reactions absorb heat, so they are endothermic.

Answer 22

thermal decomposition

Question 23

Thermal decomposition reactions _________ ______, so they are endothermic.

Answer 23

absorbs heat

Question 24

Thermal decomposition reactions absorb heat, so they are _____________.

Answer 24

endothermic

Question 25

Name a piece of equipment you would use to check if an endothermic reaction had taken place.

Answer 25

thermometer

Question 26

A reaction has taken place, and as a result the mixture has cooled. What type of reaction has taken place?

Answer 26

endothermic

Question 27

When sodium hydrogencarbonate (bicarbonate of soda) is added to a solution of citric acid, the solution becomes cold. Is this an exothermic or endothermic reaction?

Answer 27

endothermic

Question 28

What name is given to a reaction that takes in energy from the surroundings?

Answer 28

endothermic

Question 29

To find the ___________ _______ we always do the maximum energy - reactants energy

Answer 29

activation energy

Question 30

To find the activation energy we always do the ____________ _______ - reactants energy

Answer 30

maximum energy

Question 31

To find the activation energy we always do the maximum energy - __________ ______

Answer 31

reactants energy

Question 32

Would the temperature of a reaction vessel during an endothermic reaction increase, decrease or stay the same?

Answer 32

decrease

Question 33

What name is given to a reaction that gives out energy to the surroundings?

Answer 33

exothermic

Question 34

Photosynthesis is a reaction in plants that produces carbohydrates from water and carbon dioxide. It requires energy from sunlight. Is this an exothermic or an endothermic reaction?

Answer 34

endothermic

Question 35

Before a reaction between two particles can happen, the particles need to have a minimum amount of energy. What name is given to this minimum amount of energy?

Answer 35

activation energy

Question 36

In an exothermic reaction, which is greater: the energy released from forming new bonds, or the energy needed to break existing bonds?

Answer 36

energy released from forming new bonds

Question 37

In an endothermic reaction, which is greater: the energy released from forming new bonds, or the energy needed to break existing bonds?

Answer 37

energy needed to break existing bonds

Question 38

When calcium oxide reacts with water, the energy that is released when new bonds form in the product is greater than the energy that is needed to break the bonds in the reactants. What type of reaction is this?

Answer 38

exothermic

Question 39

During a chemical reaction, is energy supplied or released when bonds are broken?

Answer 39

supplied

Question 40

When ethanoic acid reacts with sodium carbonate, the energy that is needed to break the existing bonds in the reactants is greater than the energy that is released when new bonds form in the products. What type of reaction is this?

Answer 40

endothermic

Question 41

During a chemical reaction, is energy supplied or released when bonds are formed?

Answer 41

released

Question 42

True or false? A chemical change involves an energy change.

Answer 42

true