Heat and materials (C14,15) Flashcards
Name 4 temperature scales
kelvin
farenheit
celsius
centrigrade
What is the zeroth law of thermodynamics
If A is in TE with B and B is in TE with C then A is in TE with C
What defines celsius scale
0 is the triple point (solid, liquid gas)
100 is steam point
What is a thermometric propety?
What changes due to temperature (e.g. volume, pressure)
Whats an advantage and disadvantage of mercury thermometers
Expands uniformly as it conducts heat well
expensive and poisonous
What is an advantage and disadvantage of alcohol based thermometer
Large expansion
wets surface
what is the absolute scale and what is based on
0 is when there is no internal energy –> kelvin
what is absolute zero in celsius
-273 deg C
Describe the particle model of a solid
essentially touching
often crystalline
vibration
strong electrostatic attraction
What is brownian motion
this is the random collisions of particles
Why do objects expand as they heat up
PE rises, the vibrations increase The rupulsion (proton to proton) increases quicker than the attraction (proton to electron) so the equlibrium shifts out
What is internal energy
sum of potential and kinetic energy
what is absolute zero
when a substance has zero kinetic energy
What happens to temperature when state changes
stays the same
Why is bond energy negative
as energy must be supplied to break the bonds
How can SHC be determined
mixing with a pre determined substance
measuring their masses and the temperature change
(energy is equal)
What is latent heat of fusion
energy to change state between solid and liquid or liquid to solid
What is latent heat of vaporisation
energy to change state between liquid to gas or vice versa
What is a mole
the number of atoms in 12g of carbon-12
Formula for number of atoms
N = n*Na
number of moles * avogadros
Formula for mass
number of moles * molar mass
6 ideal gas assumptions
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
What is gas pressure
molecules colliding with thei contaoners and as there is a change in momentum there is a force exerted
What is Boyle’s law
p inversely proportional to volume
What is charles law
volume is proportional to temperature
gay lussac
p is proportional to temperature
What is n in pV=nRT
number of moles
whats is N in pV=NkT
Number of molecules
What’s the average velocity of gas particles in a container
0 (vector)
How is root mean square speed calculator
square everything
find mean
square root
What does the Maxwell-Boltzmann curve show
the whole range of speeds in a substance
Temperature is proportional to
Kinetic energy and therefore related to the speed
What must temperature always be in
kelvin
Why are there few lighter molecules in our atmosphere
they reached excape velocity
internal energy for an ideal gas is
only kinetic
