Energy Change

Question 1

exothermic vs endothermic
surrounding temp rise/fall?

Answer 1

Exo -> rise
Endo -> fall

exo -> release energy to surrounding
endo -> absorb energy from surrounding

Question 2

all chemical reactions involve…

Answer 2

energy change, surroundings

Question 3

example exothermic reaction

Answer 3

in heat packs
MgO + Acid

Question 4

endothermic vs exothermic

Answer 4

exo
1. heat energy given out, surroundings
2. temp, surroundings rise
3. energy change negative
4. break bonds

Question 5

exothermic reaction e.g.

Answer 5

1. combustion, fuel (i.e. burn charcoal)
2. rust iron, corrode metal
3. respiration
4. neutralisation
5. make bonds

Question 6

endothermic reaction e.g.

Answer 6

dissolve ammonium salt
photosynthesis
film photography

Question 7

energy lvl, profile diagram
H2o
used for wat?

Answer 7

for any (aq) soln. reaction i.e. aq sodium hydroxide

page 19 https://docs.google.com/document/d/1Ep_FO9CxYSFbxmf3Zqg9mgm9NNyt2enpfMDr49gufrU/edit?tab=t.0

Question 8

reversible reaction

exothermic or endothermic?

Answer 8

forward: exothermic
backward: endothermic

Question 9

define Triangle H

Answer 9

change in energy, reaction

Question 10

how to find out reaction endo/exo w/ energy

Answer 10

depends, break/make bonds, need more energy?
i.e. 25kJ energy break O2 bond, 20 kJ energy bond O and N

1. (break o2 bonds form O, O) 25kJ

minus

2. (form O, N bonds for NO) 20kJ

= +5kJ