Thermal Physics

Question 1

what are volume, pressure and temperature

Answer 1

macroscopic (large-scale) properties.
if one is changed, at least one of the others will change.
they depend on how much gas is present, experiments must have a fixed gas

Question 2

what is boyles law

Answer 2

(volume and pressure)
for a fixed mass of gas at constant temp, volume is inversely proportional to applied pressure
[pressure x volume= constant]

Question 3

boyles law

why must oil have a low vapour pressure

Answer 3

oil content will change with pressure, in turn causing mass to change

Question 4

boyles law

explain the use of the hand/foot pump

Answer 4

we very slowly inc pressure. compressing gas warms it slightly therefore after every compression wait a few moments for temp to dec

Question 5

boyles law

what is isothermal

Answer 5

the same temperature

Question 6

what is charles law

Answer 6

(volume and temperature)
for a fixed mass of gas at constant pressure, volume is directly proportional to Kelvin temp
[V/T=constant]

Question 7

pressure law

why must water be stirred regularly

Answer 7

to ensure trapped air is same temp as water

Question 8

charles law

what is the purpose of the concentrated sulfuric acid

Answer 8

traps and dries air to give better results

Question 9

charles law

what is length y

Answer 9

a measure of volume of air
vol=πr² x h

Question 10

charles law

what must water be stirred regularly

Answer 10

to ensure trapped air is same temp as water

Question 11

charles law

what does a vol-temp(celcius) graph show

Answer 11

for a fixed mass of gas at constant pressure, volume increases uniformly with temp

Question 12

what is the pressure law

Answer 12

(volume and temperature)
for a fixed mass of gas at constant volume, pressure is directly proportional to the kelvin temperature
[P/T=constant]

Question 13

simple

state the ideal gas equation

Answer 13

pV/T=constant

p₁V₁/T₁ = p₂V₂/T₂

Question 14

what is a mole

Answer 14

the amount of substance which contains as many particles as there are atoms in 0.012kg of carbon 12

Question 15

avogadros number

Answer 15

6.02x10²³mol⁻1

Question 16

what does avogadros number mean

Answer 16

the number of particles per mole

n=no. of molecules/avogadros no.

Question 17

assumptions for kinetic theory

to define characteristics of an ideal gas

Answer 17

1. no intermolecular forces (only when molecules collide)
2. volume of molecules negligible to gas volume
3. elastic collisions (moleucles and walls)
4. time of collision negligible to time between collisions
5. molecules have constant velocity (a=0)

Question 18

moles

ideal gas equation

Answer 18

pV=nRT

Question 19

pV=nRT

what is R

Answer 19

universal gas equation

8.31Jmol⁻1K⁻1

Question 20

how to get boltzmann constant

Answer 20

k=R/avogadros number

Question 20

boltzmann constant

Answer 20

1.38x10⁻23JK⁻1

Question 20

what else is equal when p, V, T are equal

Answer 20

no. of molecules

Question 20

mean square speed

ideal gas equation

Answer 20

pV=⅓Nmc²

Question 20

boltzmann constant

ideal gas equation

Answer 20

pV=NkT

Question 20

mean square speed

Answer 20

{c²}=c²+c²+c² ÷ N
<c²>

Question 20

root mean square speed

Answer 20

c(rms)=√{c²}

Question 20

density of gas

Answer 20

p=⅓ρ{c²}

Question 20

speed and temp

kinetic energy

Answer 20

½m{c²}=NkT

kinetic energy directly proportional to Klevin temp

Question 20

what is internal gas

Answer 20

the sum of potential and kinetic energy

Question 20

what is the only energy monatomic gas possess ∴ ideal gases

Answer 20

translational kinetic energy

Question 20

what is specific heat capacity

Answer 20

(c), the quantity of heat energy needed to raise the temp of 1kg of material by 1K

units J kg⁻1 K⁻1

Question 20

specific heat capacity equation

Answer 20

Q=mcΔT

Question 20

out of solid, liquid, gas what is the order of SHC

highest to lowest

Answer 20

gases>liquids>solids

Question 20

SHC solid practical

what is the use of the small amount of oil in the hole with the thermometer

Answer 20

to improve thermal contactbetween thermometer and metal

Question 20

SHC solid practical

what is the use of the metal being wrapped in insulator

Answer 20

to reduce heat loss, imporve accuracy

Question 20

SHC solid practical

why must the experiment continue for several minutes after the heater is switched off

Answer 20

the temp of the heater is higher than the temp of block and takes time for equilibrium to be established

Question 20

SHC liquid practical

what is the conatiner called that holds the liquid

Answer 20

calorimeter

Question 20

SHC liquid practical

why must water be stirred throughout experiment

Answer 20

temp of liquid and temp of calorimeter must be the same

Question 21

SHC liquid practical

ways to reduce error

Answer 21

• cool liquid in refridgerator to around 5° (liquid temp quickly rises until calorimeter and liquid are in equilibrium)

Question 22

SHC liquid practical

describe when the heating starts and stops

Answer 22

• begins liquid and calorimeter are below 5° below room temp
• ends liquid is 5° above room temp