Endothermic and Exothermic Reactions

Question 1

Define enthalpy

Answer 1

Enthalpy is the total energy present in the substance.

Question 2

How to calculate change in enthalpy?

Answer 2

Enthalpy of products - enthalpy of reactants

Question 3

Which reactions loses heat to its surroundings?

Answer 3

Exothermic reactions

Question 4

Which reactions has a negative enthalpy value?

Answer 4

Exothermic reactions

Question 5

Which reactions gain heat from its surroundings?

Answer 5

Endothermic reactions

Question 6

Which reactions have a positive enthalpy value?

Answer 6

Endothermic reactions

Question 7

Where would a negative enthalpy value be placed in a reaction (products or reactants)?

Answer 7

Products

Question 8

Where would a positive enthalpy value be placed in a reaction (products or reactants)?

Answer 8

Reactants

Question 9

Is bond breaking endothermic or exothermic? Explain.

Answer 9

Endothermic because it requires an input of energy

Question 10

Is bond making endothermic or exothermic? Explain.

Answer 10

Exothermic because when bonds are formed it releases energy.

Question 11

Draw an EXOTHERMIC energy diagram with activation energy labelled, transition state, products and reactants.

Answer 11

(search internet)

Question 12

Draw an ENDOTHERMIC energy diagram with activation energy labelled, transition state, products and reactants.

Answer 12

(search internet)