THERMODYNAMICS

Question 1

what is thermodynamics

Answer 1

the study of energy and its relationship to chemical systems

Question 2

what two things are needed for a thermodynamic system

Answer 2

a system and its surroundings

Question 3

define system

Answer 3

object that experiences a thermodynamic transformation.

Question 4

define surroundings

Answer 4

Any part of the universe that is in direct contact with the system is its surroundings

Question 5

what are the three types of system

Answer 5

open, closed, and isolated

Question 6

what occurs in an open system

Answer 6

heat transfer
mass transfer

Question 7

what occurs in a closed system

Answer 7

heat transfer
no mass transfer

Question 8

what occurs in an isolated system

Answer 8

no heat or mass transfer

Question 9

define work in a thermodynamic context

Answer 9

any energy transfer that is not heat

Question 10

what is internal energy also called and how can we calculate this simply

Answer 10

average total mechanical energy (kinetic + potential) of the particles that make up the system.

Question 11

what are the three types of heat transfer

Answer 11

conduction, convection, and radiation

Question 12

what is heat

Answer 12

transfer of energy from a warmer body to a cooler body

Question 13

how does conduction carry out thermal energy transfer

Answer 13

thermal energy transfer via molecular collisions, requires direct physical contact

Question 14

what is required for the particles in conduction to transfer thermal energy

Answer 14

direct physical contact

Question 15

how do molecule collisions in conduction carry out thermal energy transfer

Answer 15

higher energy molecules of one system transferring some of their energy to the lower energy molecules of the other system via molecular collisions

Question 16

what is convection

Answer 16

thermal energy transfer via fluid movements

Question 17

how does convection transfer thermal energy

Answer 17

Warm fluid moves in the direction of cooler fluid due to differences in pressure or density

Question 18

what is radiation

Answer 18

Radiation is thermal energy transfer via electromagnetic waves

Question 19

what does the first law of thermodynamics state

Answer 19

energy of the system and its surroundings is always conserved

Question 20

what is Q

Answer 20

Q = Quantity of heat supplied to the system by its surroundings

Question 21

What is W

Answer 21

W = Net work done by the system

Question 22

what happens in the change in internal energy equation when work is done on the system

Answer 22

Work done on system = + W

Question 23

what happens in the change in internal energy equation when work is done by the system

Answer 23

Work done by system = - W

Question 24

what happens in the change in internal energy equation when heat is added to a system

Answer 24

Heat added to system = +Q

Question 25

what happens in the change in internal energy equation when heat is given off by a system

Answer 25

- Heat given off by system = -Q

Question 26

how do you calculate change in internal energy

Answer 26

Change in U = +/-Q +/- W

Question 27

what is the second law of thermodynamics trying to prove

Answer 27

heat cannot be completely changed to work in a cycle-like process

Question 28

what does the second law of thermodynamics show about heat transfer direction

Answer 28

allows for the determination of the preferred direction of a given transformation – for example, we know that heat flows from a hot source to a cold source

Question 29

what is the symbol and unit for internal energy

Answer 29

U Joule

Question 30

what is the symbol and unit for temperature

Answer 30

T Kelvin

Question 31

what is the symbol and unit for pressure

Answer 31

P Pascal

Question 32

what is the symbol and unit for volume

Answer 32

V m^3

Question 33

what is the symbol and unit for enthalpy

Answer 33

H kJ mol-1

Question 34

what is the symbol and unit for entropy

Answer 34

S JK mol^-1 (joules per kelvin)

Question 35

what is the symbol and unit for gibbs free energy

Answer 35

G kJ mol-1

Question 36

what is internal energy

Answer 36

collective energy of molecules

Question 37

in a system with constant volume and no work what is the internal energy the same as

Answer 37

heat

Question 38

for internal energy to be equated to heat, what is the condition

Answer 38

1. constant volume 2. no work done

Question 39

what is temperature an example of

Answer 39

thermodynamic property

Question 40

in fluid, temperature is directly proportional to what

Answer 40

the translational kinetic energy of its molecules

Question 41

in gas, what happens if the translation energy per mole of gas increases

Answer 41

greater the temperature greater pressure

Question 42

how do you convert from Celsius to Kelvin

Answer 42

0 celsius = 273.15K + 273.15 to whatever required then every 1kelvin = 1Celsius

Question 43

convert 30 celsius water to kelvin

Answer 43

273.15 + 30 = 303.15 kelvin

Question 44

if a pot of water is at 303.15 and you increase it by 1 celsius, what is the water temperature in kelvin

Answer 44

304.15 kelvin 31°C

Question 45

what is enthalpy's basic law

Answer 45

H = internal energy + (pressure x volume)

Question 46

what is standard enthalpy of formation

Answer 46

enthalpy to make one mole of compound from elements

Question 47

what is enthalpy used to approximate

Answer 47

heat

Question 48

what is the equation for change in enthalpy

Answer 48

Products - reactants

Question 49

what does hess' law state

Answer 49

when adding reactions, their enthalpies can be added because enthalpy is a state function

Question 50

what is an exothermic value in enthalpy

Answer 50

-ΔH enthalpy of products is less than enthalpy of reactants

Question 51

what is an endothermic value in enthalpy

Answer 51

+ΔH enthalpy of products is more than enthalpy of reactants

Question 52

what is entropy

Answer 52

degree of disorder in a system

Question 53

what state of matter has the highest entropy

Answer 53

gas

Question 54

how does entropy increase

Answer 54

solid to a liquid to a gas

Question 55

why does gas have a higher entropy than water

Answer 55

gas molecules exhibit an increased random motion of movement

Question 56

what does gibbs free energy determine

Answer 56

if a reaction is spontaneous or not, or if the reaction is at equilibrium

Question 57

what is the equation for gibbs free energy

Answer 57

∆G = ΔH - (T x ΔS)

Question 58

what happens if ∆G is less than 0 [at constant pressure]

Answer 58

spontaneous

Question 59

what happens if ∆G is 0

Answer 59

in a state of equilibrium

Question 60

what happens if ∆G is more than 0 [at constant pressure]

Answer 60

not spontaneous