Week 1 ThermoChemistry

Question 1

Energy
Work
Heat

Answer 1

Energy: Capacity to do work
Work: Result of force acting through a** distance **
Heat: Flow of** thermal energy** due to **temperature difference **

Question 2

Two types of energy and their difference

Answer 2

Kinetic energy: due to motion
Potential energy: due to position or compositon

Question 3

What are 4 examples of Kinetic Energy

Answer 3

Mechanic energy: ordered motion of macroscopic objects
Thermal energy: disorganized, random motion by atoms and molecules
Radiant energy: Movement of EM waves/photons
Electrical energy: Movement of charges in a conducting material

Question 4

3 Examples of Potenial energy

Answer 4

Chemical energy: relative positions of electrons and nuclei in atoms and molecules
Nuclear energy: interaction of neutrons and protons in nucleus
Gravitational potential energy: heigh of an object from Earths gravitational field

Question 5

First Law of thermodynamics

Answer 5

𝝙E(uni)=0
𝝙E(sys)=-𝝙E(surr)
The change in energy of the surroundings has the oppisite sign to the change in energy of the system

Question 6

Internal Energy
How does this work with reactants/products?

Answer 6

The sum of the potential and kinetic energy of all the particles in the system
If changes in internal energy is negative, rectants have higher internal energy than products
If changes in internal energy is positive, products have higher internal energy than products

when theres no subscript, assume it refers to the system (E=E(sys))

Question 7

If the system gives out energy to the surroundings, is 𝝙E(sys) +,-

Answer 7

Negative

Question 8

Energy Exchange (𝝙E), what is the equation

Answer 8

The transfer of internal energy from the surroundings to the system can be in the form of heat or work
𝝙E=q+w

Question 9

Work equation
Also what is 1 L x atm= to in J

Answer 9

w=-P𝝙V(force times distance)
101.325 J

Question 10

Heat/Thermal energy (what is a measure of T.E)

Answer 10

Heat is the echange of thermal energy due to TEMP difference
Thermal energy is associated with the random and disorganized motiion of particles
Temperature is a measure of thermal energy

Question 11

Extensive/Intensive Heat Capacities
(examples)

Answer 11

Extensive=depends on the amount of substance heated (C)
Intensive= does not depend on the amount of substance being heated (Cs or Cm)

Question 12

State function/Examples

Answer 12

Depends on the initial and final ONLY
𝝙E, P, V, T, H is a state function
q, w NOT state functions

Question 13

Enthalpy

Answer 13

The sum of the internal energy and the product of pressure and volume
H=E+PV
Useful for studying chemical reactions at constant pressure

Question 14

Enthalpy change is equivalent to…

Answer 14

Hear at constant pressure
𝝙H=q(p)

Question 15

What are the 2 types of calorimetry, how does one decide which type to use?

Answer 15

Constant Volume, Constant Pressure
Constant volume= 𝝙E=q(v constant)
Constant Pressure= 𝝙H=q(p constant)