⭐️Calorimetry Flashcards
Temperature
Measures average KINETIC ENERGY of particles (not heat energy) HIGHER TEMP=HIGHER KINETIC ENERGY, despite phase
Kelvin equation
K=’C+273 (in reference table)
Celsius equation w kelvin
‘C=K-273
Fahrenheit equation
‘F=9/5(C)+32
Celsius equation w Fahrenheit ⭐️
‘C=5/9(F-32)
What is currently used in thermometers and why?⭐️
Alcohol w red food coloring bc it has a low FP and high BP, mercury causes neurological damage
Kinetic molecules theory (KMT) ⭐️
1) matter is composed of smaller particles atoms
2) particles move in continuous motion (unless absolute 0)
3) collisions w each other result in transfer of energy
Specific heat (Cp)
Amount of heat energy (Joules) needed to raise 1g of a substance by 1’C
Heat energy absorbed/released equation
q=(m)(delta T)(Cp)
Calculating final temp
Solve for delta T.
If it says “absorbed”, add delta T to given temp.
If it says “released/given off”, subtract delta T from given temp.
Heat loss=heat gain when solving for final temperature
OBJECT DROPPED INTO WATER
(m)(temp-Tf)(Cp)=(m)(Tf-temp)(Cp)
Simplify each side (multiply/distribute) and then solve for Tf
Remember, cm3=g
Pure liquid ⭐️
Infinite freezing point (never freezes)
Pure solid ⭐️
Infinite melting point (never melts)
Vapor
Gaseous phase of a substance that is a solid/liquid at room temp (type of gas)
When is IMF (intermolecular force) strongest? ⭐️
If it has a high BP, lower vapor pressure
Sublimation
Solid to gas
WEAK IMF
“Dry ice” CO2
Iodine (I2)
Endothermic
Heat absorbed, uses joules
Solid phase heat curve
Kinetic/temp change
q=(m)(deltaT)(2.06 J/g’C)
Melting/freezing heat curve
Potential energy change
q=(m)(334 J/g)
Heat of fusion/heat of solidification
Liquid phase heat curve
Kinetic/temp change
q=(m)(deltaT)(4.18 J/g’C)
Boiling/vaporization/condensation heat curve
Potential energy change
q=(m)(2260 J/g)
Heat of condensation/heat of vaporization
(NOT evaporation bc there are bubbles)
Vapor/gas phase heat curve
Kinetic/temp change
q=(m)(deltaT)(2.02 J/g’C)
Heat of fusion (Hf)
Amount of heat energy needed to melt a substance at its melting point 334J/g
Heat of solidification
Amount of heat energy needed to freeze a substance at its freezing point 334J/g
Heat of vaporization (Hv)
Amount of heat energy needed to vaporize a substance at its boiling point 2260J/g
Heat of condensation
Amount of heat energy needed to condense a substance at boiling point 2260 J/g
When does the vapor pressure solid=vapor pressure liquid?
Melting/freezing point 0’C during phase change
When does the vapor pressure liquid=atmospheric pressure?
Boiling point 100’C during phase change (NOT necessarily heat of vaporization)
Gas shape/volume
Take shape/volume
Liquid shape/volume
Take shape/definite volume
Solid shape/volume
Definite shape/volume
Exothermic
Releasing heat
Multi step heat curve problems
Find joules for temp change, phase change, and any additional temp change. Add joules to get answer
Calculation tips
Round to lowest sig fig of given numbers
You can wait until end to round to sig fig but u don’t have to
Specific heat of ice
2.06
Specific heat of vapor
2.02
If a 200mL pool of water and a 2000mL pool of water are 27’C, which one has more HEAT?
The 2000mL pool has more heat because temperature does not measure heat, temp measures kinetic energy.
Equilibrium
When the items have reached a similar temperature
In which direction does heat flow?
Heat flows from high temp to low
On a HEATING CURVE, what do diagonal lines represent? Is kinetic increasing/dec/or staying the same? Is Potential incr/decr/or staying the same?
Kinetic energy is rising, while potential energy is staying the same.
On a COOLING CURVE, what do diagonal lines represent? Is kinetic increasing/dec/or staying the same? Is Potential incr/decr/or staying the same?
Kinetic energy is decreasing, while potential energy is staying the same.
On a HEATING CURVE, what do straight lines mean? Is kinetic increasing/dec/or staying the same? Is Potential incr/decr/or staying the same?
Kinetic energy stays the same, while potential increases
On a COOLING CURVE, what do straight lines mean? Is kinetic increasing/dec/or staying the same? Is Potential incr/decr/or staying the same?
Kinetic energy stays the same while potential decreases
What does vapor pressure depend on?
Current atmospheric pressure
Heat loss=heat gain
(m)(deltaT)(Cp)=(m)(deltaT)(Cp)
