19.1 Flashcards

Internal energy and temperature

1
Q

when does energy transfer between two objects take place

A

if one objects exerts a force on the other object casting it to move ( does work on the other object)

if one object is hotter than the other object so the energy transfer of heat takes place via conduction, convection or radiation 9 energy is transferred due to the temperature difference)

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2
Q

explanation of why brakes heat up

A

the world done by the frictional force between the brake pads and the tyres heats the break pads which gain energy from the kinetic energy of the vehicle

temp increases and the internal energy of the break pad increases

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3
Q

what is the internal energy of an object due to its temperature called

A

thermal energy

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4
Q

what is the internal energy of an object increased because of

A

energy transfer by heating the object

work done on the object

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5
Q

what does it mean if the internal energy of an object stays constant

A

no energy is transferred by heating and no work is done

energy transferred by heating and work done balance each other out

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6
Q

the first law of thermodynamics

A

the change of internal energy of an object =
the total energy transfer due to work done and heating

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7
Q

why are the atoms in a solid held together

A

due to the forces of attraction between the electrical chases of protons and electrons

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8
Q

what are the molecules in a solid like

A

vibrate in a fixed position in a neat arrangement

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9
Q

what happens when particles gain in a solid heat up

A

they gain more kinetic energy and begin to vibrate

eventually the solid will melt when the bonds break between the molecules and they begin to move freely over each other

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10
Q

what does the energy supplied to melt a solid do to the potential energy of the molecules

A

raises them because they break free from each other

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11
Q

what are molecules like in a liquid

A

move about at random in contact with eachother
can move over each other
the forces between the molecules are not strong enough to hold them in fixed positions

when the temperature of a liquid is raised the kinetic energy of the liquid increases and the particles have sufficient energy to break away from each other and vaporise the liquid

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12
Q

molecules in a gas

A

move in random speeds in random directions further apart than in a liquid

heating a gas causes the particles to gain kinetic energy and speed up

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13
Q

what is the internal energy of an object

A

the sum of the random distribution of the kinetic and potential energies of molecules

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14
Q

hotter object =

A

more internal energy

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15
Q

what is thermal equilibrium

A

when no overall heat transfer occurs because the objects are at the same temperature

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16
Q

0 degrees celcius =

A

the temperature at which pure ice melts

17
Q

100 degrees c =

A

the temperature of steam at standard atmospheric pressure

18
Q

what is the absolute scale measured in

19
Q

what is 0 K

A

absolute 0 with is the lowest posible temperature

20
Q

what is the triple point of water

A

273.16 which is the point where ice, water and water vapour coexist in thermodynamic equilibrium

21
Q

when 0k what is it in degrees

22
Q

when 373K what is it in degrees

23
Q

what does the absolute 0 temp mean

A

no object can have a temp below thus. the object has minimum internal energy

24
Q

how was the value -273 found

A

if a gas is placed in a sealed container and the pressure is measured of it at ice point and steam point is measured they will always cut the temp axis at this point despite which gas is used

25
Q

what does temp =

26
Q

t1 x p2