thermal physics

Question 1

what is internal energy

Answer 1

The sum of kinetic energy and potential energy of all the particles in an object

Question 2

what is the first law of thermodynamics

Answer 2

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

Question 3

what is one of the ways energy transfer can take place

Answer 3

if one object does work on the other object

Question 4

how can a heat energy transfer take place

Answer 4

if one object is hotter than the other energy can be transferred by convection conduction or radiation

Question 5

what is specific heat capacity

Answer 5

the energy needed to raise the temperature of a unit mass of a substance by 1K without a change of state

Question 6

what assumptions would you make when estimating how long it takes for water to turn into ice

Answer 6

energy continues to be lost to the
surroundings at the same constant
rate
 the temperature of the ice
formed does not fall below 0 °C

Question 7

state one similarity and difference for the motion of particles of two different temperatures

Answer 7

both random motion

different mean kinetic energies

Question 8

name two assumptions of the motion of particles in an ideal gas

Answer 8

random movement of the particles
collisons are elastic
they do not attract each other
volume of molecules negligible compared with the volume of gas

Question 9

what is an ideal gas

Answer 9

a gas under conditions such that it obeys boyle’s law

Question 10

what is boyle’s law

Answer 10

at a constant temperature the pressure and volume of a gas are inversely proportional

Question 11

what does the temperature rise of an object depend on

Answer 11

mass of the object
amount of energy supplied to it
substance/substances from which it is made

Question 12

what is charles’ law

Answer 12

at a constant pressure the volume of a gas is directly proportional to its absolute temperature

Question 13

what is brownian motion

Answer 13

the zigzag random motion of particles suspended in a fluid

Question 14

what did the discovery of brownian motion provide

Answer 14

evidence for exisistance of atoms

Question 15

what is the pressure law

Answer 15

for a fixed mass of ideal gas at constant volume it’s pressure is directly proportional to its absolute temperature

Question 16

what is the avogrado constant

Answer 16

number of atoms in exactly 12g of carbon 12

Question 17

what is thermal energy

Answer 17

The internal energy of an object due to its temperature

Question 18

how can the internal energy of an object increases

Answer 18

if the object is heated

if work is being done on the object

Question 19

what is happening if the internal object remains constant

Answer 19

energy transfers by work done and heating balance out

there is no energy transfer by heating or work done

Question 20

what is specific latent heat of fusion

Answer 20

energy needed to change state of unit mass

of solid to liquid without temperature change

Question 21

what is specific latent heat of vaporisation

Answer 21

energy needed to change the state of unit mass

of liquid to gas without temperature change

Question 22

what is sublamation

Answer 22

when a solid vaporises directly when heated

Question 23

what is molar mass

Answer 23

the mass of one mole of a substance

Question 24

what is absolute 0

Answer 24

lowest possible temperature

temperature at which an object has minimum internal energy

Question 25

how do you calculate work done by an ideal gas

Answer 25

work=pressure x volume