Energetics Flashcards

1
Q

bond breaking is (exothermic/endothermic)

A

endothermic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

bond forming is (exothermic/endothermic)

A

exothermic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Endothermic reactions (release/absorb) energy

A

absorb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Exothermic reactions (release/absorb) energy

A

release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Endothermic reactions are (cold/hot)

A

cold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Exothermic reactions are (cold/hot)

A

hot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Endothermic reactions have a (positive/negative) delta H

A

positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Exothermic reactions have a (positive/negative) delta H

A

negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Temperature

A

average kinetic energy of a substance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Heat

A

the total kinetic energy of a substance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Units of heat

A

Joules (J) or kilojoules (kJ)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Specific heat capacity

A

the joules of heat that are needed to raise the temperature of one gram of a substance by one Kelvin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

units of specific heat capacity

A

J/g/K

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

q/delta H/energy change =

A
mc delta T
M = mass of the substance being heated
C = SHC
Delta T = temperature change
Unit of q is J
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

SHC calculations could be inaccurate due to:

A

Lack of insulation

Heating the container/vessel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Ways to improve accuracy of SHC calculation:

A

Insulate calorimeter

Use a lid on the calorimeter

17
Q

Which reactions have a negative enthalpy change (negative delta H)?

A

neutralisation, combustion

18
Q

Standard enthalpy change of formation

A

energy change when 1 mole of a substance is formed from its elements in their standard state

19
Q

Standard state

A

pure form of the substance at STP

20
Q

Standard enthalpy change of combustion

A

energy change when 1 mole of a substance is burnt at STP

21
Q

Enthalpy of formation of oxygen

A

zero

22
Q

Enthalpy change of a reaction =

A

enthalpy of formation of the products - enthalpy of formation of the reactants

23
Q

Lower energy means (more/less) stable

A

more

24
Q

Average bond enthalpy

A

the energy needed to break one mol of a bond in a gaseous molecule averaged over similar compounds

25
Q

Average bond enthalpy calculations

A

find the enthalpy for each compound, ones on the left are positive, ones on the right are negative, then sum up

26
Q

Why are ozone bonds easier to break than oxygen bonds?

A

Ozone has a resonance structure, so the bonds average out to 1.5, which makes it easier to break than O2, which has a double bond