Thermochemistry - Nature of Energy Flashcards
1
Q
What is thermochemistry?
A
The study of energy changes during physical or chemical changes in matter
2
Q
What do all thermodynamics depend on?
A
The law of conservation of energy
3
Q
The law of conservation of energy states…
A
Energy cannot be created nor destroyed
4
Q
Potential Energy (PE)
A
- Energy due to the position or composition of an object
- Stored Energy
5
Q
Examples of Potential Energy
A
- Gravitational PE
- Elastic PE
- Chemical PE
6
Q
Kinetic Energy (KE)
A
- Energy of motion
- Depends on mass of object and its velocity
7
Q
Calculation of thermal energy
A
Thermal Energy=PE + KE
8
Q
Changes that occur in matter may be classified into….
A
Physical, chemical or nuclear changes
9
Q
Physical Change
A
- Change in form or state of a substance
- No chemical bonds are broken
- Least energy
10
Q
Example of physical change
A
Hydrogen boils at -252℃
11
Q
Chemical Change
A
- Change in chemical bonds between atoms resulting in new substances
12
Q
Example of chemical change
A
Hydrogen is burned as fuel in the space shuttle’s engine
13
Q
Nuclear Change
A
- Change in the protons or neutrons in an atom resulting in a new atom
- Most energy
14
Q
Example of nuclear change
A
- Hydrogen undergoes nuclear fusion in the sun
- Produces helium
15
Q
What is a System?
A
The substance undergoing a change
16
Q
What are the surroundings?
A
- Describes the system’s environment
- Includes all matter that is not part of the system
