unit 5 - Exothermic and endothermic reactions

Question 1

What does an exothermic reaction do?

Answer 1

transfers thermal energy to the surroundings leading to an increase in the temperature of the surroundings

Question 2

what does an endothermic reaction do?

Answer 2

takes in thermal energy from the surroundings, leading to a decrease in the temperature of the surroundings

Question 3

is delta H negative for exothermic or endothermic reactions?

Answer 3

exothermic reactions

Question 4

is delta H positive for exothermic or endothermic reactions?

Answer 4

endothermic reactions

Question 5

what is enthalpy change (delta H)

Answer 5

transfer of thermal energy during a reaction

Question 6

what is activation energy?

Answer 6

minimum energy that colliding particles must have to react

Question 7

is bond breaking endothermic or exothermic process?

Answer 7

endothermic process

Question 8

is bond making endothermic or exothermic process?

Answer 8

exothermic process

Question 9

what goes in the x axis of the reaction profile?

Answer 9

progress of reaction

Question 10

what goes in the y axis of the reaction profile?

Answer 10

energy

Question 11

where does bond breaking occur?

Answer 11

between reactants and peak (endothermic)

Question 12

where does bond making occur?

Answer 12

between peak and product (exothermic)

Question 13

examples of endothermic reactions (or exothermic)

Answer 13

dissolving and precipitatione

Question 14

examples of exothermic reactions

Answer 14

displacement/substitution and neutralisation

Question 15

formula for overall energy change

Answer 15

product - reactants

Question 16

what is the overall energy change between?

Answer 16

reactants and products

Question 17

what is the activation energy between?

Answer 17

reactants and peak

Question 18

where do reactants get their energy from?

Answer 18

around them (take thermal energy so surrounding feels cold = endothermic reaction) [to make products]

Question 19

what happens to the temperature in exothermic reactions?

Answer 19

increases

Question 20

what happens to the temperature in endothermic reactions?

Answer 20

decreases