chem 2 - exam 1

Question 1

energy (definition)

Answer 1

the capacity to do work or produce heat

Question 2

internal energy (E)

Answer 2

the sum of a system’s energy including its kinetic and potential energy

ΔE system = - ΔE surroundings

ΔE = E products - E reactants = q + w

Question 3

enthalpy (H)

Answer 3

definition: the sum of internal energy and the product of P and V (ie: H = E + PV)

ΔH = q : change in enthalpy is equal to the heat lost or gained by the reaction/system

Question 4

standard state conditions

Answer 4

25°C or 298.15L
1 atm

Question 5

standard enthalpy of formation (ΔH°f)

Answer 5

the amount of heat lost or gained when 1 MOLE OF A COMPOUND is formed

ΔH°f

Question 6

second law of thermodynamics

Answer 6

all spontaneous changes cause and increase in the entropy/disorder of the universe

class: “for a process to be spontaneous, the entropy of the universe must increase”

+ΔS universe

• to compensate for the increase in ΔS universe, reactiosn pay some of their final energy loss/gain; a heat tax; energy dissipates (disappears)

Question 7

spontaneous

Answer 7

a reaction/process that does not require outside energy to take place; (because) the collection of products is more stable than the reactants

product favored
increase in disorder

Question 8

spontaneity

Answer 8

think of it as “the likelihood that a reaction will form product”

Question 9

entropy (S)

Answer 9

a thermodynamic state function that measures the dispersal of energy and matter of a system

Question 10

Gibbs Free Energy (G)

Answer 10

the amount of energy in a system that is available to do useful work (at a constant temperature and pressure)

ΔG°= ΔH° - TΔS°

Question 11

ΔG°= ΔH° - TΔS°

entropy or enthalpy driven?

Answer 11

ΔH° is bigger than TΔS° : ENTHALPY (HEAT) DRIVEN

TΔS° is bigger than ΔH° : ENTROPY (SPONTANEOUS) DRIVEN

Question 12

activation energy

Answer 12

the energy threshold that must be overcome to produce a chemical reaction