Heat and materials (C14,15)

Question 1

Name 4 temperature scales

Answer 1

kelvin
farenheit
celsius
centrigrade

Question 2

What is the zeroth law of thermodynamics

Answer 2

If A is in TE with B and B is in TE with C then A is in TE with C

Question 3

What defines celsius scale

Answer 3

0 is the triple point (solid, liquid gas)

100 is steam point

Question 4

What is a thermometric propety?

Answer 4

What changes due to temperature (e.g. volume, pressure)

Question 5

Whats an advantage and disadvantage of mercury thermometers

Answer 5

Expands uniformly as it conducts heat well

expensive and poisonous

Question 6

What is an advantage and disadvantage of alcohol based thermometer

Answer 6

Large expansion

wets surface

Question 7

what is the absolute scale and what is based on

Answer 7

0 is when there is no internal energy –> kelvin

Question 8

what is absolute zero in celsius

Answer 8

-273 deg C

Question 9

Describe the particle model of a solid

Answer 9

essentially touching
often crystalline
vibration
strong electrostatic attraction

Question 10

What is brownian motion

Answer 10

this is the random collisions of particles

Question 11

Why do objects expand as they heat up

Answer 11

PE rises, the vibrations increase
The rupulsion (proton to proton) increases quicker than the attraction (proton to electron) so the equlibrium shifts out

Question 12

What is internal energy

Answer 12

sum of potential and kinetic energy

Question 13

what is absolute zero

Answer 13

when a substance has zero kinetic energy

Question 14

What happens to temperature when state changes

Answer 14

stays the same

Question 15

Why is bond energy negative

Answer 15

as energy must be supplied to break the bonds

Question 16

How can SHC be determined

Answer 16

mixing with a pre determined substance
measuring their masses and the temperature change
(energy is equal)

Question 17

What is latent heat of fusion

Answer 17

energy to change state between solid and liquid or liquid to solid

Question 18

What is latent heat of vaporisation

Answer 18

energy to change state between liquid to gas or vice versa

Question 19

What is a mole

Answer 19

the number of atoms in 12g of carbon-12

Question 20

Formula for number of atoms

Answer 20

N = n*Na

number of moles * avogadros

Question 21

Formula for mass

Answer 21

number of moles * molar mass

Question 22

6 ideal gas assumptions

Answer 22

large number of gas particles
random direction, random speeds
elastic collisions
time during collisions is neglible
electrostatic forces only matter in collisions
particles operate a neglible volume compared to gas

Question 23

What is gas pressure

Answer 23

molecules colliding with thei contaoners and as there is a change in momentum there is a force exerted

Question 24

What is Boyle’s law

Answer 24

p inversely proportional to volume

Question 25

What is charles law

Answer 25

volume is proportional to temperature

Question 26

gay lussac

Answer 26

p is proportional to temperature

Question 27

What is n in pV=nRT

Answer 27

number of moles

Question 28

whats is N in pV=NkT

Answer 28

Number of molecules

Question 29

What’s the average velocity of gas particles in a container

Answer 29

0 (vector)

Question 30

How is root mean square speed calculator

Answer 30

square everything
find mean
square root

Question 31

What does the Maxwell-Boltzmann curve show

Answer 31

the whole range of speeds in a substance

Question 32

Temperature is proportional to

Answer 32

Kinetic energy and therefore related to the speed

Question 33

What must temperature always be in

Answer 33

kelvin

Question 34

Why are there few lighter molecules in our atmosphere

Answer 34

they reached excape velocity

Question 35

internal energy for an ideal gas is

Answer 35

only kinetic