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Course InformationCourse Information
Course Web Site
Syllabus OWL Grading Lecture Schedule
Laboratory
ThermodynamicsThermodynamics
“Thermodynamics is a funny subject. The first time you go through it, you don't understand it at all. The second time you go through it, you think you understand it, except for one or two small points. The third time you go through it, you know you don't understand it, but by that time you are so used to it, it doesn't bother you anymore.”
Arnold Sommerfeld, German theoretical physicist
What is What is Thermochemistry?Thermochemistry?
(aside from being (aside from being loads of funloads of fun, of course!), of course!)
Thermochemistry is the study of the relationship of heat and chemical reactions
Can tell us Whether a reaction will occur What drives a reaction In complex, systems, we can use
thermochemistry in combination with structural information to help elucidate mechanisms
The wonderful things you The wonderful things you can do with can do with
Thermochemistry Thermochemistry oror
How aminoglycoside How aminoglycoside antibiotics kill bacteriaantibiotics kill bacteria
Studying small changes in the heat absorbed or evolved by the system can tell us how this works
DNA RNA (bacteria use different
“machinery”)
Protein
/
Aminoglycoside-rRNA BindingAminoglycoside-rRNA Binding
Energy and Chemical ReactivityEnergy and Chemical Reactivity
Types of EnergyTypes of Energy
The First Law of The First Law of ThermodynamicsThermodynamics
Conservation of Energy= Energy is neither created nor destroyed
This means that Euniverse = 0
During a chemical or physical change, energy will be transformed from one type to another
Energy InterconversionEnergy Interconversion
Wind moves turbine
Turbine produces electricity
Electricity is used to lyse water into H2
and O2
H2 is stored and then burned
J kJ cal kcal BTU kWh
1 J = 1 0.001 0.2390 2.390 x 10-4 1055 2.778 x 10-7
1 kJ = 1000 1 239.0 0.2390 1.0557 2.778 x 10-4
1 cal = 4.184 4.184 x 10-3 1 0.001 252 1.162 x 10-6
1 kcal = 4184 4.184 1000 1 0.252 1.162 x 10-3
1 kWh = 3.6 x 106 3.6 x 103 8.604 x 105 860.4 2.93 x 10-4 1
Energy UnitsEnergy Units
Read as 1J = 0.2390 cal
Temperature and HeatTemperature and Heat
Heat (q) and Temperature (T) are not the same!
The more thermal energy something has, the greater the motion of its atoms
The total thermal energy in an object is the sum of the individual energies of all the atoms, molecules, or ions
What happens to thermal (heat) What happens to thermal (heat) energy?energy?
Warms another object (transfer)
Causes a change of state
Is used in an endothermic reaction
Which statement below best describes the Which statement below best describes the process of placing a thermometer initially at process of placing a thermometer initially at
22ºC into ice water?22ºC into ice water?
1 2 3 4
25% 25%25%25%1. Some of the thermal energy of
the ice water is transferred to the thermometer.
2. Some of the thermal energy of the thermometer is transferred to the ice water, melting some of the ice.
3. The atoms of mercury begin to move faster as a result of the thermal energy transfer between the thermometer and the ice water.
4. The mercury in the thermometer begins to expand as a result of the thermal energy transferred.
Heat TransferHeat Transfer
If heat (q) is transferred, in which direction does it go? From hotter to cooler (related to the 2nd Law,
but we’ll get to that later) Heat lost = Heat gained (1st Law)
qwarmer = -qcooler
Thermal equilibrium= when two objects in contact reach the same temperature
System and SurroundingsSystem and Surroundings
System = The thing under study Surroundings = Everything else in the
universe Energy transfer between system and
surroundings Exothermic- system gives off heat Endothermic- system takes in heat
Heat TransferHeat Transfer
When I heat an object, how much energy will it require? It depends . . .1. Quantity (How much stuff do I have?)
2. Size of the temperature change
3. Identity of the material
TmCq
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