Midterm-Definitions

Question 1

Energy

Answer 1

the capacity to do work ( force acting through a distance)

the ability of one physical system to do work on in another physical system

Question 2

Types of energy

Answer 2

Kinetic Energy
Potential Energy (Electrical, Chemical, Mass)
Thermal Energy
Radiant Energy

Question 3

Kinetic energy

Answer 3

energy required to move objects

Question 4

Electrical energy

Answer 4

energy associated with the forces of attraction and/or repulsion between charged particles

Question 5

Chemical energy

Answer 5

Energy resulting from the net attraction of the electrons and nuclei in molecules and compounds

Question 6

Radiant energy

Answer 6

energy associated with electromagnetic radiation

Question 7

Thermal energy

Answer 7

The total energy of random movements of molecules Thermal energy is related to the kinetic energy of particles

Question 8

Mass energy

Answer 8

Source of energy released in nuclear reactions

Question 9

Thermodynamics

Answer 9

The study of energy transfers and transformations

“how much energy goes where”

Question 10

System

Answer 10

whatever we want to describe and study by itself.

Question 11

Surroundings

Answer 11

everything else but the system

Question 12

Boundary

Answer 12

what separates the system from its surroundings

Question 13

Conservation of Energy (First Law of Thermodynamics)

Answer 13

Energy is neither created nor destroyed in any process, although it may be transferred from one body to another or transformed from one form into another

Question 14

What does the change in temperature depend on?

Answer 14

on the amount of heat transferred, q
on the direction of heat flow
inversely on the amount of material
on the identity of the material

Question 15

Actual temperature (T) vs Difference in temperature (ΔT)

Answer 15

Actual temperature (T): different for the Celsius and Kelvin scales - 0°C = 273.15 K
Difference in temperature (ΔT):  is the same for the Celsius and Kelvin scales - an increase of 10°C =  an increase in 10 K

Question 16

Heat capacity

Answer 16

quantity of energy required to increase the temperature of a sample by 1°C

Question 17

What does heat capacity depend on?

Answer 17

mass and type of material

Question 18

Specific heat capacity (Cs)

Answer 18

measure of a substance’s intrinsic ability to absorb heat

amount of heat energy required to raise the temperature of one g of a substance by 1°C

Question 19

Molar heat capacity

Answer 19

amount of heat energy required to raise the temperature of one mole of a substance by 1°C

Question 20

In liquids and solids, what types of forms does kinetic energy come in?

Answer 20

In liquids
-rotations
-vibrations
-translations
In solids 
-vibrations only

Question 21

What is the equation showing the direction of heat transfer?

Answer 21

q surroundings = –q system

What is lost by one is gained by the other

Question 22

Identify the relationship between the delta T and the heat capacity.

Answer 22

• smaller the heat capacity, bigger the delta T

- when heat capacities are the same, the temperatures must be equal as well

Question 23

Work

Answer 23

energy used to move and object against an opposing force

Question 24

What happens to the work when you push and pull on a piston inside a cylinder?

Answer 24

Expansion: wsys < 0
Contraction: wsys > 0

Question 25

what is required in a system to do work?

Answer 25

Must have expansion or contraction in order to do work, so these two systems with the same volume does no work.

Question 26

State functions vs Path functions

Answer 26

State Functions: Properties that depend only on the current state of a system and not on the way the system acquired that state.
Example) E, H, S, G, p, V, m, composition
Path Functions (the opposite!) Properties that describe the transition of a system from one state to another. Examples: q, w

Question 27

Is energy, heat and work path functions or state functions?

Answer 27

Energy is a state function, but heat and work are path functions

Question 28

State the definition of path independence.

Answer 28

The energy change in a chemical reaction is independent of the manner in which the reaction takes place.