Ch - 10 (Thermal Properties of Matter) Flashcards

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1
Q

What happens when thermal expansion takes place?

A
  • Temp increases
  • Volume increases
  • molecules move faster
  • molecules move farther
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2
Q

Which state of matter expands the most?

A

Gas > Liquid > Solid

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3
Q

If an object tht is small and big expanded, which one would expand faster and why?

A

The one that is bigger because it has more particles.

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4
Q

What is an example of expansion in real life?

A
  • The railway tracks.
  • When there is a gap there is no buckling.
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5
Q

What is an example of contraction in real life?

A
  • Power towers with pylons.
  • They are not straight tied so they do not contract.
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6
Q

What happens when a material expands?

A
  • Particles don’t get bigger
  • They move around more and take up more space.
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7
Q

Define specific heat capacity.

A

Energy needed to raise temperature of 1kg of the substance by 1°C.

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8
Q

What is the formula for thermal energy?

A

Mass (kg) x speciofc heat capacity (Jkg°C) x Temp change

E = mv delta T

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9
Q

What is the formula for energy transferred?

A

Mass (kg) x specific latent heat (Jkg)

E = ml

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10
Q

Define latent heat.

A
  1. Energy transferred in a process without the change of the body’s temperature.

Or

  1. Heat or energy that is absorbed or released during a phase of a substance.
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11
Q
A
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12
Q

What is internal energy made up of?

A

KE
Chemical PE

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13
Q

What happens of we supply thermal energy to an object?

A

Gain KE

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14
Q

What is the specific heat capacity of water?

A

4200 J/kg°C

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15
Q

What is the specific heat capacity of aluminium?

A

910 J/kg°C

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16
Q

What is the specific heat capacity of polythene?

A

2300 J/kg°C

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17
Q

What is the specific heat capacity of steel?

A

420 J/kg°C

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18
Q

What is the specific heat capacity on land and water? And what warms up quickly?

A

Land: lower SHC = heats up faster

Water: Higher SHC = heats up slower

Land

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19
Q

Which state/s does thermal expansion happen in?

A

Solids, liquids, gases

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20
Q

What are the applications of thermal expansion?

A
  • Thermometers (liquid expands with temp)
  • Switches (bimetallic strip bends upwards)
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21
Q

What are the consequences of thermal expansion?

A
  • Solids: Buckle if too hot.
  • Ex: Metal railway tracks, Road surfaces, bridges
22
Q

Define internal energy.

A

The total energy stored inside a system by the particles that make up the system due to their motions and positions.

23
Q

What affects the kinetic energy?

A

Motion of the particles

24
Q

What affects the potential energy?

A

position of the particles relative to each other

25
Q

What can the increase in KE (IE) do?

A
  • Temp increases
  • Change of state
26
Q

What factors affect how much the temp of a system increases?

A
  • Mass
  • Type of material
  • Amount of thermal energy into system
27
Q

Define fixed points.

A

The melting and boiling points of pure water are known as fixed points.

28
Q

What temp does ice melts?

A

0°C

29
Q

What temp does pure water boil at?

A

100°C

30
Q

What happens when a substance is changing state?

  • melting or freezing
  • boiling or condensing
A

The substance does not change temperature

31
Q

What happens during boiling?

A
  • Thermal energy supplied
  • at b.p., temp does not increase (internal energy does not rise)
  • additional thermal energy overcomes intermolecular forces
  • liquid evaporates
32
Q

What is another name for evaporation?

A

Vaporisation

33
Q

How is the process reversed?

A

Cooling energy is transferred away

  • A gas turns into a liquid (condensation)
34
Q

What happens during melting?

A
  • ice is heated using thermal energy
  • at m.p. Temp does not change (internal energy not rising)
  • additional thermal energy overcomes intermolecular forces in solid.
  • solid turns to liquid from melting
  • heat transferred away and it freezes
35
Q

Define heating.

A

Energy is transferred to the system and the KE of molecules increases (arrow to right)

36
Q

Define cooling.

A

Energy is transferred away from the system (dissipates to surroundings)

37
Q

Define the procces of condensation.

A
  • Lose KE and move slowly
  • no enough energy to overcome intermolecular forces
  • particles get close together
  • particles flow over each other
  • gas condenses to liquid (no change of themp)
38
Q

Define the process of solidification.

A
  • particles lose KE and move slowly
  • don’t have energy to overcome intermolecular forces
  • particles get close togetehr
  • vibrate in fixed position n it turns from liquid to solid.
39
Q

What does a heating/cooling curve if a substance show?

A

Energy changes the temp is increased/decreased

40
Q

Define evaporation.

A

Change in state of a liquid to gas

41
Q

When does evaporation happen?

A
  • at any temp
  • only from surface of liquid
42
Q

How is the energy in a liquid?

A
  • molecules have range of energy
  • average energy relates to temp of liquid
43
Q

When does evaporation occur?

A
  • more energetic molecules move near to the surface of the liquid. Particles evaporate
  • average energy of liquid is reduced
  • liquid is cooled down by evaporation
44
Q

What affects the rate of evaporation?

A

Temperature, SA, air movements

45
Q

What happens when temp is increased for evaporation?

A
  • KE of molecules increases
  • molecules overcome intermolecular forces (holds in liquid to escape from sueface)
  • High temp –> High SA
46
Q

What happens when SA increases for evaporation?

A

Molecules only escape the intermolecular forces of attraction at the surface of the liquid.

47
Q

How does air movement affect evaporation?

A
  • dries air and allows more water movement
48
Q

What happens in evaporation and cooling?

A
  • An object in contact with an evaporating liquid, both solid and liquid cools.
  • refrigerator and air conditioner
49
Q

Define boiling.

A

Change in state from liquid to gas.

50
Q

When does boiling happen?

A
  • happens only at b.p.
  • happens all through the liquid