Exam 3 Chapter 5

Question 1

heat

Answer 1

heat (q): transfer or thermal energy between two bodies at different temperatures

Question 2

thermal energy

Answer 2

kinetic energy associated with the random motion of atoms and molecules

Question 3

temperature

Answer 3

quantitative measure of “hot” or “cold”

Question 4

Energy

Answer 4

the capacity to supply heat or do work

Question 5

Exothermic Process

Answer 5

change that releases heat
ex: combustion reaction using a torch

Question 6

Endothermic Process

Answer 6

reaction or change that absorbs heat
ex: a cold pack

Question 7

calories (cal)

Answer 7

amount of energy required to raise one gram of water by one degree C (or 1 degree K)

Question 8

Joule (J)

Answer 8

amount of energy used when a force of 1 newton moves an object 1 meter
SI unit of heat, work, and energy

Question 9

1 calorie =

Answer 9

4.184 Joules

Question 10

heat capacity (C)

Answer 10

the quantity of heat (q) a body of matter absorbs or releases when it experiences a temperature change of 1 degree C (or 1 degree K)

C = q/deltaT

Question 11

specific heat capacity (c)

Answer 11

quantity of heat required to raise the temperature of 1 gram of substance by 1 degree C (or 1 degree K)

c = q/(mdeltaT)
q = (specific heat)(mass of substance)*(temperature change)

Question 12

calorimetry

Answer 12

way to measure the amount of heat involved in a chemical process

Question 13

system

Answer 13

the substance(s) undergoing the chemical/physical change

Question 14

surroundings

Answer 14

all other matter apart from the system, including the measurement apparatus, that serves to provide heat to the system or absorb heat from the system

Question 15

calorimeter

Answer 15

device used to measure the amount of heat involved in a chemical or physical process

Question 16

qreaction + qsolution =

Answer 16

0

Question 17

qreaction =

Answer 17

-qsolution

Question 18

bomb calorimeter

Answer 18

used to measure the energy produced by reactions that yield large amounts of heat and gaseous products, such as in combustion reactions

Question 19

1st Law of Thermodynamics

Answer 19

change in internal energy of a system (U) is equal to the heat and work of the system
*Law of Conservation of Energy
deltaU = q + w

Question 20

Enthalpy (H)

Answer 20

the sum of a system’s internal energy (U) and the product of its pressure and volume
is a state function
H = U+ PV

Question 21

Hess’s Law

Answer 21

if a process can be written as the sum of several stepwise processes, the enthalpy change of the total process equals the sum of the enthalpy changes of the various steps
*this is valid because enthalpy is a state function