chapter 3 👹👹👹

Question 1

Carnot Cycle

Answer 1

method to convert heat to work

Question 2

thermal efficiency (eq 3.1)

Answer 2

ratio of net work produced to the heat input, want to make thermal efficiency as large as possible

Question 3

Steps of Carnot Heat Engine

Answer 3

Converts heat into work by
1) isothermal expansion (heat absorbed)
2) adiabatic expansion (pressure drop)
3) isothermal compression (heat rejected)
4) adiabatic compression (volume decreases, pressure rises)

Question 4

what terms cancel in carnot energy balance?

Answer 4

internal energy, kinetic, potential, Wec

Question 5

What is the difference between the Carnot Heat Pump and the Carnot Heat Engine?

Answer 5

The pump reverses every step of the carnot cycle and is used as a refrigerator or freezer. REQUIRES work, absorbs heat from a cold reservoir and rejects heat to a warm reservoir.

(think extracting heat from a cold outside to pump into a warmer house)

Question 6

Coefficient of Performance (COP)

Answer 6

ratio of heat transferred from the cold reservoir to the work required (mirror of thermal efficiency)

Question 7

Energy of Mixing

Answer 7

Change in Internal Energy of Mixing = Internal energy of Mixture - (amount in the mixture) (internal energy of pure components)

Question 8

Enthalpy of Mixing

Answer 8

Change in Enthalpy of Mixing =Enthalpy of Mixture - (amount in the mixture) (enthalpy of pure components)

Question 9

Volume of Mixing

Answer 9

Change in Volume of Mixing =Volume of Mixture - (amount in the mixture) (Volume of pure components)

Question 10

Ideal Gas Mixture Properties (relating to internal energy)

Answer 10

ideal gas molecules do not have intermolecular potentials so the internal energy consists entirely of kinetic properties -> when components are mixed at constant T and P, U is just the sum of the component internal energies (kinetic energies)

Question 11

Energy of Mixing, Volume Change of Mixing, and Enthalpy Change of Mixing for an ideal gas are all equal to……..

Answer 11

0

Question 12

Ideal Solution

Answer 12

no synergistic effects of the components being mixed, each component operates independently

Question 13

Enthalpy (heat) of mixing, Energy of Mixing, and Volume of Mixing for an ideal solution are all equal to ……….

Answer 13

0

Question 14

Stoichiometric Numbers

Answer 14

v1c1=v2c2

The v’s, negative for reactants and positive for products
-> say how many molecules there are

Question 15

Stoichiometric Coefficient

Answer 15

absolute value of stoichiometric numbers

Question 16

Reaction Coordinate

Answer 16

Chi

nout= nin + chi (sum of v)

Question 17

Hess’ Law

Answer 17

enthalpy change of a reaction can be calculated by summing any component reactions, or by calculating the reaction enthalpy along a convienient reaction pathway between the reactants and the products.

Question 18

Standard State

Answer 18

a state for a pure substance at a specified (T,P) and type of phase (S,L,V) at which enthalpies of components are found. requires all specifications as a Reference State except T.

Question 19

Standard state Heat/Enthalpy of Reaction

Answer 19

decompose reactants into constituent elements in their naturally occurring states at the standard state conditions and then reform them into their products

Question 20

Standard Heat/Enthalpy of Formation

Answer 20

enthalpy of forming a substance from the constituent elements

Question 21

Exothermic

Answer 21

negative enthalpy

Question 22

Endothermic

Answer 22

positive enthalpy

Question 23

Work effects in a reactive system

Answer 23

Shaft work and Wec can be neglected in a reactive system energy balance

Question 24

can the carnot cycle ever be 100% efficient?

Answer 24

t the conversion of heat energy into mechanical energy cannot be 100% efficient, even if every operation in the process is 100% efficient.