Chapter 3: Energy and its Conservation Flashcards
3.1-3.6
What are the 4 types of energy?
Kinetic energy
Potential energy
Thermal energy
Radiant energy
What is kinetic energy?
Energy of movement (dependant on the velocity (v) and mass (m) of an object
What is electrical energy?
Energy from positive and negative ions held a small distance apart
What is chemical energy?
Attraction of the electrons and nuclei in molecules (bond energy)
What is thermal energy?
Total energy of random movements of molecules
What is radiant energy?
Energy as a result of electromagnetic radiation
What is thermodynamics?
The study of energy transfers and transformations
What is the first law of thermodynamics?
Energy is neither created nor destroyed, only transferred or transformed from one form into another
What is heat?
Thermal energy that is exchanged with its surroundings
What is heat capacity?
The quantity of heat required to raise the temperature of the system by 1 degrees celsius or 1 k. Depends on the mass of the heated object
What is molar heat capacity?
The amount of heat needed to raise the temperature of 1 mol of substance by 1 degrees celsius
What is specific heat capacity?
The amount of heat required to raise the temperature of 1 gram of the substance by 1 degree celsius of 1 k
Do we have to keep track of the signs associated with heat flows? (is energy transfer directional?)
Yes. If Tf<Ti, then delta T should be negative
What is work?
The energy used to move an object against an opposing force (W surroundings = -W system)
What is a state function?
Properties that depend only on the conditions that describe the system (ex. energy)
What are path systems?
Depend on how the change occurs (ex. distance; multiple paths to the same spot)
Are state and path functions dependant on one another?
No.
Bond breakage ______ energy
Bond formation ________ energy
Requires
Releases
What is bond energy? (BE)
Energy required to break a bond (always positive)
Is the amount of energy released or absorbed in a chemical reaction proportional to the amounts of chemicals that react?
Yes (molar ratios)
What do bond energies depend on?
- The types of atoms that are bonded together
- The type of bond between two similar atoms
- In polyatomic atoms BE depends on the rest of the molecular structure (ex multiple carbons might have different BE even though they are the same element)
What does a calorimeter measure?
Heat flow from a chemical reaction
What is the difference between a constant-pressure calorimeter and a constant-volume calorimeter?
Constant-pressure: The volume is changing (used for studying liquids) (styrofoam cup)
Constant-volume: Pressure is changing (used for studying gases) (bomb calorimeter)
Does an open system mean constant-pressure, or volume?
Is there work?
What is changing?
Constant-pressure
Yes
Volume
