8A.2 Heat Transfer Flashcards
as molecules move what happens to neighbor molecules and apply that to solids
as a molecule moves. their bonds can pull neighboring molecules, meaning a lattice vibration in the solid can pass energy through the solid
what happens when a rod is being heated from one side
the molecules on the side being heated are vibrating faster and further, compared with the molecules on the side away from the heat source where they move slowly.
the molecules from the hot side will pull the one with less energy as they share it evenly with the faster one slowing down and the slow one speeding up, the effect of these transfers increases the internal Kinetic energy which is caused by heating (particles) moves throughout the substance
heat is only referred when
one energy is moved from one object/material to another.
Transferred heat energy affects the temp of an object depending on 3 things what are they
- the amount of heat energy transferred
- the mass of the object
- the specific heat capacity of the material from which an object is made from
what is the specific heat capacity
the energy required to raise the temperature of 1 Kilogram, of a substance by 1 degree kelvin
what is the equation to measure the amount of energy transferred to a material
E = mc(change in Temp)
what are the Si units of specific heat capacity
J/Kg*K
how can we measure specific heat capacity experimentally
meausre the heat energy put into a known mass of material while insulating it very well making sure that all of the heat is used to raise the temp, (there I think with temp, msdd and heat energy you can then find yk the C)
how can we measure specific heat capacity experimentally
measure the heat energy put into a known mass of material while insulating it very well making sure that all of the heat is used to raise the temp, (there I think with temp, mass, and heat energy you can then find yk the C)
Note: more insulation better result
immersion heaters must never
have their tops under water as steam may be produced in side the heater which makes this explode
what are the safety notes required to know when finding the specific heat capacity experimentally
- the heaters and the metal blocks will get hot enough to burn your skin
- immersion heaters must never have their tops under water as steam maybe be produced inside the heater which causes an explosion
for an object thats already at the temp to change states (like a solid at its melting them) what is additionally needed to for it to melt
the input of additional energy which does not raise the temp but is used to break bonds between the molecules to change the state
the amount of additional energy needed to change the state of a substance is determined by (2 things)
- the mass of the substance
- the specific latent heat of fusion/vaporisation
what is specific latent heat
the energy required to change the state of one kilogram of a substance at a constant temp
why is the specific heat capacity not needed when changing the state
because temp change is always zero at any phase change
what is the formula to calculate the addition energy in to change state
E = Lm
what is specific latent heat of fusion for
melting
what is specific latent heat of vaporisation
boiling
how can we calculate the specific latent heat of fusion of water
get a funnel full of ice a beaker under it and a weighing scale, then place an immersion heater within the ice making sure that all the heat goes towards melting the ice, then take another funnel of ice and without heating let it melt for the same time as the first funnel from there you can find the change in mass and you already have the additional energy in so find L
to change state, molecules gain
potential energy as this is accociated with the bonds between the molecules
potential energy is negative so increasing it means
getting closer to zero
