Entropy/Enthalpy

Question 1

What is the definition of temperature?

Answer 1

a measure of the average kinetic energy of the particles in a system.

Question 2

True or False: Heat and temperature are the same thing.

Answer 2

False

heat measures the transfer of thermal energy, while temp measures how much particles move

Question 3

What is heat?

Answer 3

energy transferred between systems or objects with different temperatures.

Question 4

Fill in the blank: The SI unit of temperature is ____.

Answer 4

Kelvin

Question 5

What is heat capacity?

Answer 5

the amount of heat required to change the temperature of a substance by one degree Celsius.

Question 6

True or False: Specific heat capacity is the heat capacity per unit mass.

Answer 6

True

Question 7

What is the formula for calculating heat (Q)?

Answer 7

Q = mcΔT, where m is mass, c is specific heat capacity, and ΔT is the change in temperature.

Question 8

What is enthalpy?

Answer 8

the total heat content of a system.

Question 9

Multiple Choice: Which of the following is the correct unit for enthalpy?

Answer 9

Joules (J)

Question 10

What does the symbol ΔH represent?

Answer 10

change in enthalpy.

Question 11

True or False: Enthalpy can be directly measured.

Answer 11

False

Question 12

Fill in the blank: The law of conservation of energy states that energy cannot be ____ or ____.

Answer 12

created; destroyed

Question 13

What is the relationship between enthalpy and heat in a constant pressure process?

Answer 13

In a constant pressure process, the change in enthalpy equals the heat absorbed or released.

Question 14

What is entropy?

Answer 14

a measure of the disorder or randomness of a system.

Question 15

True or false: Entropy tends to decrease in isolated systems.

Answer 15

false

increase

Question 16

True or False: A decrease in entropy indicates a more ordered system.

Answer 16

True

Question 17

What is the Second Law of Thermodynamics?

Answer 17

The Second Law states that the total entropy of an isolated system can never decrease over time.

Question 18

Fill in the blank: The unit of entropy is ____.

Answer 18

Joules per Kelvin (J/K)

Question 19

What is specific heat capacity?

Answer 19

the amount of heat required to raise the temperature of one kilogram of a substance by one degree Celsius.

Question 20

True or False: Water has a high specific heat capacity.

Answer 20

True

Question 21

What is the effect of temperature on the kinetic energy of particles?

Answer 21

As temperature increases, the kinetic energy of particles also increases.

Question 22

What is the formula for calculating change in temperature (ΔT)?

Answer 22

ΔT = T_final - T_initial

Question 23

What happens to the entropy of a system when it undergoes a phase change from solid to liquid?

Answer 23

The entropy increases.

Question 24

Fill in the blank: The heat required for a phase change is called ____.

Answer 24

latent heat

Question 25

What does the term 'thermal equilibrium' refer to?

Answer 25

the condition where two objects in contact do not exchange heat, meaning they are at the same temperature.

Question 26

True or False: Heat always flows from a cooler object to a warmer object.

Answer 26

False

Question 27

What is the relationship between heat capacity and temperature change?

Answer 27

Higher heat capacity means a smaller temperature change for a given amount of heat.

Question 28

What is the significance of the critical point in thermodynamics?

Answer 28

The critical point is the temperature and pressure at which the distinction between liquid and gas phases disappears.

Question 29

What is the formula for calculating the change in enthalpy during a reaction?

Answer 29

ΔH = H_products - H_reactants

Question 30

Fill in the blank: The process of heat transfer without a medium is called ____.

Answer 30

radiation

Question 31

What is the term for the measure of energy dispersal in a system?

Answer 31

Entropy

Question 32

True or False: A reversible process is one that can proceed in both directions without increasing the entropy of the universe.

Answer 32

True

Question 33

What is the significance of the Gibbs free energy in thermodynamics?

Answer 33

Gibbs free energy indicates the maximum reversible work that can be performed by a thermodynamic system at constant temperature and pressure.

Question 34

Fill in the blank: The change in Gibbs free energy is given by the equation ΔG = ΔH - TΔS, where T is the ____.

Answer 34

temperature

Question 35

What is the effect of increasing temperature on the entropy of an ideal gas?

Answer 35

Increasing temperature increases the entropy of an ideal gas.

Question 36

What does it mean if a process is exothermic?

Answer 36

An exothermic process releases heat to the surroundings.

Question 37

Multiple Choice: Which of the following is an example of an endothermic process?

Answer 37

Melting of ice

Question 38

What is the heat of fusion?

Answer 38

The heat of fusion is the amount of heat required to convert a unit mass of a solid into a liquid without a change in temperature.

Question 39

True or False: The heat of vaporization is greater than the heat of fusion for most substances.

Answer 39

True

Question 40

What does the term 'thermal conductivity' refer to?

Answer 40

Thermal conductivity is a measure of a material's ability to conduct heat.

Question 41

What is the effect of pressure on the boiling point of a liquid?

Answer 41

Increasing pressure raises the boiling point of a liquid.

Question 42

True or false: (-) q is endothermic because heat is absorbed, while (+) q is exothermic because heat is released

Answer 42

false ## Footnote (-) q is exothermic because heat is released, while (+) q is endothermic because heat is absorbed

Question 43

What is the change in enthalpy of fusion?

Answer 43

The change in enthalpy of fusion is the amount of energy required to change a substance from solid to liquid at its melting point.

Question 44

True or False: The change in enthalpy of vaporization is always greater than the change in enthalpy of fusion for a given substance.

Answer 44

True

Question 45

What does a positive change in enthalpy indicate?

Answer 45

the process is endothermic, absorbing heat from the surroundings.

Question 46

Which of the following processes involves change in enthalpy of vaporization? A) Melting B) Boiling C) Freezing

Answer 46

B) Boiling

Question 47

What is typically the unit for measuring enthalpy changes?

Answer 47

Kilojoules per mole (kJ/mol)

Question 48

Short answer: How does temperature affect enthalpy of vaporization?

Answer 48

Generally, the enthalpy of vaporization decreases with increasing temperature.

Question 49

What is the relationship between enthalpy of fusion and enthalpy of vaporization for water?

Answer 49

The enthalpy of vaporization for water is significantly higher than the enthalpy of fusion due to the stronger intermolecular forces that must be overcome.

Question 50

True or False: The enthalpy of fusion is the same for all substances.

Answer 50

False

Question 51

What is the enthalpy change when ice melts to water called?

Answer 51

Enthalpy of fusion

Question 52

what is q = mL

Answer 52

* q = heat absorbed/released during phase changes * m = mass * L = latent heat of fusion or vaporization

Question 53

how many J is in 1 cal?

Answer 53

4.184 J

Question 54

What is spontaneity in the context of chemistry?

Answer 54

Spontaneity refers to a process that occurs without needing to be driven by an external force.

Question 55

True or False: A spontaneous reaction always occurs quickly.

Answer 55

False

Question 56

Fill in the blank: A spontaneous process is generally characterized by a decrease in ______ energy.

Answer 56

free

Question 57

What is the role of Gibbs free energy in determining spontaneity?

Answer 57

A reaction is spontaneous if the change in Gibbs free energy (ΔG) is negative.

Question 58

Multiple choice: Which of the following factors can affect the spontaneity of a reaction? A) Temperature B) Pressure C) Concentration D) All of the above

Answer 58

D) All of the above

Question 59

What is the significance of the second law of thermodynamics in relation to spontaneity?

Answer 59

It states that the total entropy of an isolated system can never decrease, which supports the concept of spontaneous processes increasing overall disorder.

Question 60

True or False: All spontaneous reactions are exothermic.

Answer 60

False

Question 61

What does a positive ΔS indicate about the spontaneity of a process?

Answer 61

It suggests that the process is more likely to be spontaneous due to an increase in entropy.

Question 62

Fill in the blank: A reaction with a negative ΔH and a positive ΔS is always ______.

Answer 62

spontaneous (exothermic)

Question 63

What is the impact of temperature on a reaction that has a positive ΔH and a negative ΔS?

Answer 63

The reaction will be non-spontaneous (endothermic) at all temperatures.

Question 64

the more molecule that spread, the _______ the entropy will be

Answer 64

more

Question 65

when products are greater than reactants, what's the effect on the change in entropy?

Answer 65

ΔS will be positive

Question 66

**E**ric **R**eads **F**iction **I**nside

Answer 66

**E**xothermic **R**eleased **F**orms **I**ncreased

Question 67

**E**than **A**te **B**ad **D**inner

Answer 67

**E**ndothermic **A**bsorbed **B**roken **D**ecreased