Thermodynamics/Thermochemistry & Work/Energy

Question 1

What is a system?

Answer 1

the matter being observed, the total amount of reactants and products in a chemical reaction

Question 2

What is an isolated system?

Answer 2

A system that cannot exchange energy (heat and work) or matter with the surroundings?

Question 3

Energy can be transferred in the forms of

Answer 3

• Work: mechanical
• Electrically
• Heat: thermodynamics
• Radiation

Question 4

What is a closed system?

Answer 4

A system that can exchange energy (heat and work) but not matter with the environment

Question 5

What is an open system?

Answer 5

A system that can exchange both energy (heat and work) with the surroundings
ex: a boiling pot of water

Question 6

What is the equation for the first law of thermodynamics?

Answer 6

Delta U=Q-W

Question 7

Describe an isothermal process

Answer 7

The temperature is constant–so there is no heat added t making Q, Q=W so the heat added to a system is equal to the work done by the system–so U is Zero
Delta U=0

Question 8

What is a process?

Answer 8

When a system undergoes a change in one or more of its properties

Question 9

____ processes occur when no heat is exchanged between the system and the environment

Answer 9

Adiabatic

Question 10

Describe the properties of an Adibatic process

Answer 10

-no heat is exchanged so Q=0

so Delta U will equal -W so the change in internal energy is equal to the work done ON the system since W is negative

Question 11

A ____ process occurs when the pressure of the system is constant

Answer 11

Isobaric

Question 12

How does the graph of an isobaric process appear?

Answer 12

Straight line, with a slope of zero

Question 13

A ____ process experiences no change in volume

Answer 13

Isovolumetric (Isochoric) System

Question 14

Delta U = Q in what type of system and why?

Answer 14

Isovolumetric.

If the volume is constant (no compression or expansion), no work is being done so W=0 leaving Delta U=Q

Question 15

How does an isovolumetric graph appear?

Answer 15

Vertical Line

Question 16

___ is the transfer of energy from one substance to another as a result in differences in temperature

Answer 16

Heat

Question 17

_____ is the average kinetic energy of the particles of a substance

Answer 17

Temperature

Question 18

_____ states that objects are in thermal equilibrium when their temperatures are equal

Answer 18

Zeroth law of thermodynamics

Question 19

What does the first law of thermodynamics state?

Answer 19

The change in total internal energy of a system is equal to the difference in amount of energy transferred into the system and the amount of energy transferred out of the system

Question 20

Heat is a _____ function not a _____ function

Answer 20

Process, state

Question 21

What are the most important process functions

Answer 21

Work (W) and Heat (Q)

Question 22

What is a process function?

Answer 22

The way by which an equilibrium state is reached

Question 23

The processes in which heat is absorbed (Q>0) is

Answer 23

endothermic

Question 24

The process in which heat is released (Q<0) is

Answer 24

exothermic

Question 25

Enthalpy (H) is equivalent to heat (Q) under

Answer 25

constant pressure

Question 26

What is calorimetry

Answer 26

Measuring transferred heat

Question 27

What is the equation for heat given a specific heat

Answer 27

q=mc(delta T)

where q is the heat absorbed or released and c is the specific heat

Question 28

What is specific heat?

Answer 28

the amount of energy needed to raise the temperature of one gram of substance by one degree Celsius ( or one Kelvin)

Question 29

Mass times specific heat is

Answer 29

heat capacity

Question 30

Temperature is related to ______ of particles of a substance

Answer 30

average kinetic energy

Question 31

What is the measurement of Delta T during phase change

Answer 31

zero