5.1 Thermal

Question 1

absolute zero

Answer 1

the temperature at which a substance has minimal internal energy; the lowest limit for temperature

Question 2

thermal equilibrium

Answer 2

when there is no net heat flow between two substances in contact with eachother

Question 3

kinetic model of matter

Answer 3

all matter is made of very small particles that are in constant motion.

Question 4

Internal energy

Answer 4

the sum of all the randomly distributed kinetic and potential energies of all the particles in a system

Question 5

Brownian motion

Answer 5

the random movement of small visible particles suspended in a fluid due to collisions with much smaller, randomly moving particles of the fluid

Question 6

specific heat capacity (definition)

Answer 6

the amount of energy needed to raise the temperature of 1kg of a substance by 1K

Question 7

Specific heat capacity (equation)

Answer 7

E=mcT

c=E/mT

Question 8

Specific heat capacity (investigation)

Answer 8

Use a circuit with a voltmeter and an ammeter to measure V and I. Use a stopwatch to time how long it takes to raise the temperature of the substance by 20K. Use VIt=mcT and rearrange for c

Question 9

Specific latent heat of fusion (Definition)

Answer 9

The amount of energy required to change the phase of 1kg of substance from a solid to a liquid

Question 10

Specific latent heat of fusion (Investigation)

Answer 10

Two ice funnels, measure the difference in mass of water melted, use L=VIt/(change in mass)

Question 11

Specific latent heat of vaporisation (Definition)

Answer 11

The amount of energy required to change the phase of 1kg of substance from a liquid to a gas

Question 12

Specific latent heat of vaporisation (Investigation)

Answer 12

Vaporise and condense water, measure mass of amount condensed. Equate VI(1)t=mL(1) + Q and VI(2)t=mL(2) + Q
Equate to get L=t(P1-P2)/(m2-m1)

Question 13

Mole

Answer 13

amount of substance that contains as many particles as exactly 12.0g of carbon 12.

Question 14

Avogadro’s constant

Answer 14

Na=6.02 x 10^23 mol^-1

Question 15

N=nNa

Answer 15

Number of particles = Avogadro’s constant x Number of moles

Question 16

Ideal gas

Answer 16

A gas that has internal energy only in the form of random kinetic energy

Question 17

Derive (1/2)mv^2 = (3/2)kT

Answer 17

pV=(1/3)Nmc^2 pV=NkT
(1/3)Nmc^2 = NkT
(1/3)mc^2 = kT
mc^2 = 3kT
(1/2)mc^2 = (3/2)kT

Question 18

Boyle’s Law

Answer 18

pV = constant

Question 19

Boyle’s law (investigation)

Answer 19

Pressure gauge connected to an air column. Plot Pressure against 1/Volume. Gradient should be a straight line

Question 20

pressure temperature law

Answer 20

p/T = constant

Question 21

Pressure- temp law (investigation)

Answer 21

Fixed mass of gas sealed in a flask submerged in water. Water is heated to different temperatures, pressure of gas in flask is measured. plot pressure against temperature. Gradient should be a straight line and can be extrapolated to find a value for absolute zero.

Question 22

Charles’ law

Answer 22

V/T = constant

Question 23

Boltzmann constant (equation)

Answer 23

k=R/Na