UNIT SEVEN

Question 1

thermodynamics

Answer 1

every chemical reaction accounted for by change in energy

Question 2

thermochemistry

Answer 2

study of changes in heat energy that accompany chemical reactions and physical changes

Question 3

heat

Answer 3

total of kinetic energies of particles in sample of matter

Question 4

temperature

Answer 4

measure of average kinetic energy of particles in sample of matter (measured in joules, (kg/m^2)/s^2

Question 5

heat transfer

Answer 5

when collisions between particles result in transfer of energy

Question 6

thermodynamic equilibrium

Answer 6

average kinetic energy and temperature is the same

Question 7

calorimetry

Answer 7

study of the transfer of heat

Question 8

calorimeter

Answer 8

device that measures heat absorbed/released in chemical/physical change

Question 9

3 processes of changing energy

Answer 9

1. Heating/cooling
2. Phase transitions
3. Chemical reactions

Question 10

heat of reaction

Answer 10

quantity of heat released/absorbed during chemical reaction

q=mCpAT

Question 11

specific heat (Cp)

Answer 11

amount of energy required to raise temperature of 1 g by 1C

Question 12

bond enthalpies

Answer 12

bonds formed/broken during reaction cause change in system potential energy; average energy needed to break all bonds estimated by adding average bond energies of all bonds in reactants (reactants-products)

Question 13

Hess’s Law

Answer 13

overall enthalpy change in reaction equal to sum of enthalpy changes for individual steps

Question 14

endothermic

Answer 14

when energy of system increases; energy gained from surroundings

Question 15

exothermic

Answer 15

when energy of systems decreased; energy lost gained by surroundings

Question 16

entropy (s)

Answer 16

degree of randomness in a system (higher entropy=higher disorder)

Question 17

Gibbs Free Energy

Answer 17

maximum amount of non-expansion work that can be extracted from thermodynamically closed system

Question 18

chemical kinetics

Answer 18

studies reaction rates and reaction mechanisms

Question 19

differential rate law

Answer 19

expresses rate dependent on concentration

Question 20

rate determining step

Answer 20

slowest elementary step

Question 21

catalyst

Answer 21

increases reaction rates

Question 22

chemical equilibrium

Answer 22

opposing processes occur at the same time and rate

Question 23

reversible reaction

Answer 23

chemical reaction where products react to reform reactant

Question 24

reversible chemical reaction

Answer 24

chemical equilibrium when rate of forward reaction equals rate of reverse reaction

Question 25

buffered solution

Answer 25

resists change in pH, weak acid and salt of the weak acid

Question 26

solubility constant

Answer 26

product of molar concentration of ions in saturated solution, each raised to power that is coefficient of that ion in the chemical equation

Question 27

LeChatelier’s principle

Answer 27

if system at equilibrium is subjected to stress, equilibrium shifted in stress-relieving direction

Question 28

common-ion effect

Answer 28

when addition of common ion brings precipitation/reduced ionization