Energetics

Question 1

Exothermic Reactions

Answer 1

Give off heart energy (Temperature rises).

Eg. Combutsion, Respiration

Question 2

Endothermic Reactions

Answer 2

Absorb heat energy (Temperature falls)

E.g. Thermal Decomposition

Question 3

q= MCT

Answer 3

q= Heat energy change, J
m= Mass of water heated, g
c= 4.2
T= Change in temp, Tfinal - Tstart, degrees

Question 4

Calorimertry

Answer 4

The measurement of heat energy during a chemical reaction

Question 5

Why is your answer differrent to theirs? (Calculations)

Answer 5

Becuase the heat energy will always be lost to the surroundings

Question 6

Why is the reatcion Endothermic

Answer 6

Becuase breaking bonds requires energy to be put in

Question 7

Why is the reaction Exothermic

Answer 7

Because making bonds gives energy out

Question 8

△H

Answer 8

Overall change in energy in kj/mol

Question 9

Why can calcium metal not be used in experiments?

Answer 9

Because it is too reactive

Question 10

Why is it better to use a polystyrene cup?

Answer 10

Because tit insulates heat so it cannot be lost to surroundings

Question 11

Observations that can be made during reactions

Answer 11

• Colour change
• temp change
• fizzing
• bubbles