MASTER THERMOCHEMISTRY #1: STUDY OF HEAT IN CHEMICAL REACTIONS
TYPES OF SYSTEMS
^What to catch from the above slides;
Open system: system where flow of both matter and energy is possible
Closed system: system where only flow of energy is possible
Isolated system: system where flow of neither matter nor energy is possible
Kinetic energy: energy of motion
Potential energy: stored energy (e.g. in chemical bond)
ENERGY EXCHANGE
Heat (q) and work (w) are interchangeable forms of energy
System is where the chemical reaction is taking place
Surrounding is anywhere outside of where the reaction is taking place
Whenever the system GAINS heat or energy from work, it is assigned a POSITIVE (+) sign.
Whenever the system RELEASES heat or energy by doing work, it is assigned a NEGATIVE (-) sign
FORMULAS TO MEMORIZE
Formula 1: Heat Capacity
q= heat energy
Cp = heat capacity
ΔT = change in temperature
(refer to below for units)
Formula 2: Specific Heat Capacity
q= heat energy
m = mass
Cs = specific heat capacity (=the amount of heat energy needed to raise the temperature of 1g of substance by 1°C)
ΔT = change in temperature
Formula 3: Molar heat capacity
q= heat energy
n = number of mole
Cp,m = molar heat capacity (=the amount of heat energy needed to raise the temperature of 1 mol of substance by 1°C)
ΔT = change in temperature
PRACTICE Qs ON SPECIFIC HEAT CAPACITY (BEST RESOURCES)
ANSWER KEY
EXOTHERMIC VS. ENDOTHERMIC REACTIONS
^What to catch from the above slide:
Exothermic rxn: chemical reaction where heat is released. Heat is found in the product side of the chemical equation
Endothermic rxn: chemical reaction where heat is absorbed. Heat is found in the reactant side of the chemical equation
BOMB CALORIMETER**
^What to catch from the above slide:
Bomb calorimeter is an apparatus used to measure the heat energy (q) generated or RELEASED by a given chemical reaction. The calorimeter consists of the steel bomb and water (see pic above), thus why we can come up with "q bomb" and "q water" separately.
It is always denoted with a negative sign in the front, "-q reaction" as heat is being released (exothermic, thus negative) by the chemical reaction.
PRACTICE Qs ON BOMB CALORIMETRY
ANSWER KEY
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