Chapter 8
Equation; for Calorimeters
(M (for mass))of A x (C)of A (Temp2-Temp1)= Mass of Bx Specific heat of B (Temp1-Temp2).
Water at 273 K (0 ºC)
...
Number of Joules in a calorie
1 calories=4.184 joules
Q=mL
A equation that shows how much heat is required to change a substance or system's phase. (temp has nothing to do with this).
Kinetic Energy.
All objects in motion have a kind of energy.
Specific Heat
Amount of energy required to increase the temperature of 1 substance to 1 K.
specific heat capacity (C)
Amount of heat required to raise the temperature of something by a degree .
Q = mC∆T
Calculate how much energy is gained or lost when something changes temperature.
1 calorie heat capacity of water
Causes a rise of 1 degree celcius in 1 g of water ( 1 cal/g times Celcius) .
Calorimeters
Devices that help transfer heat to one system to the other while preventing the minimum loss of heat to the enviroment.
2 types of Chemical Reactions in thermodynamics.
Endothermic reactions and exothermic reactions.
Work (Heat process).
Energy being transfered from a high energized object to a low energized object.
Law of thermodynamics.
Energy cannot be created or destroyed.
Kinetic Energy aka.
Energy of motion.
When finding Specific Heat (C)
Find how much on the table a substance's specific heat is and find out if the units is in Joules or calories.
How to calculate phase changes
Find out if the substance is changing from solid to liquid or vise versa or liquid to gas or vise versa, find out what the joules requirments are and temperatures. always use grams or kilograms for mass.
Particles of a liquid.
Have a moderate amount of Kinetic Energy.
Particles of a solid.
Have the least Kinetic Energy.
Particles of a gas.
Have the most amount of Kinetic Energy.
Exothermic
Heat being released.
Endothermic
Heat being taken in.
Law of Conservation of Energy.
Heat gained must equal the amount of heat lost.
Calorie
Heat is meausred in these terms like Joules is another common unit of meausring heat.
Calculation rules.
If the substance or system has its temperature changed use mcΔT (only temp) if its not use use the phase change equations (if they are changing physical states only) (mLfus, mLvap).
Energy release.
In order for something to get cooler.
Energy absorption.
In order for something to get warmer
m equals (Q = mC∆T)
Mass of the substance being heated or cooled can be measured in (grams) (g).
Temperature
Not dependent on energy present (an intensive property.)
How to calculate Calorimeters
Qgained-Qlost (both are set to equal each other.)
Q equals (Q = mC∆T)
The amount of energy gained or lost all together (measured in joules) (aka heat)(awnser to mC∆T).
Joules (J)
The amount of energy gained or lost measured (used in finding Q).
Heat dependency.
The amount of energy present (extensive property).
Heat (Q).
The flow of energy from an area of higher temperature to an area of lower temperature, it is aka energy process.
Latent Heat
The heat process that describes a system or substance changing phases without changing its temperature.
Latent heat of fusion (Lfus)
The heat that transforms of a solid to a liquid or a liquid to a solid.
Temperature.
The meausre of kinetic energy of all of the energy in a substance. Determines how much heat will flow when two objects are brought into contact.
Latent heat of vaporization (Lvap)
The process of a liquid to a vapor or vapor to a liquid.
Work (W)
The process of excuting the transmission of heat.
C equals (Q = mC∆T)
The specific heat of the substance being heated or cooled measured in Joules/kilo grams x Kelvins (must be in joules, kelvins and kilograms) .
Thermodynamics.
The study of energy changes accompanying physical and chemical changes.
Calculation rules #2
Use mcΔT to find the temp change plus phase change equation to calcuate the Joules.
Conservation of Energy
When two systems make contact with different temperatures, one will lose heat and one will gain heat until both reach an equilibrium, then heat transfer will cease.