Chapter 5

Question 1

bomb calorimeter

Answer 1

device designed to measure the energy change for processes occurring under conditions of constant volume; commonly used for reactions involving solid and gaseous reactants or products

Question 2

calorie (cal)

Answer 2

unit of heat or other energy; the amount of energy required to raise 1 g of water by 1 degree C; 1 cal = 4.184 J

Question 3

calorimeter

Answer 3

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

Question 4

calorimetry

Answer 4

process of measuring the amount of heat involved in a chemical or physical process

Question 5

chemical thermodynamics

Answer 5

area of science that deals with the relationships between heat, work, and all forms of energy associated with chemical and physical processes

Question 6

endothermic process

Answer 6

chemical reaction or physical change that absorbs heat

Question 7

energy

Answer 7

capacity to supply heat or do work

Question 8

enthalpy (H)

Answer 8

sum of a system’s internal energy and the mathematical product of its pressure and volume

Question 9

enthalpy change (delta H)

Answer 9

heat released or absorbed by a system under constant pressure during a chemical or physical process

Question 10

exothermic process

Answer 10

chemical reaction or physical change that releases heat

Question 11

expansion work (pressure-volume work)

Answer 11

work done as a system expands or contracts against external pressure

Question 12

first law of thermodynamics

Answer 12

internal energy of a system changes due to heat flow in or out of the system or work done on or by the system

Question 13

heat (q)

Answer 13

transfer of thermal energy between two bodies

Question 13

heat capacity (C)

Answer 13

extensive property of a body of matter that represents the quantity of heat required to increase its temperature by 1 degree C (1 K)

Question 14

Hess’s law

Answer 14

if a process can be represented as the sum of several steps, the enthalpy change of the process equals the sum of the enthalpy changes of the steps

Question 15

hydrocarbon

Answer 15

compound composed only of H and C; the major component of fossil fuels

Question 16

internal energy (U)

Answer 16

total of all possible kinds of energy present in a substance or substances

Question 17

joule (J)

Answer 17

SI unit of energy; 1 is the kinetic energy of an object with a mass of 1 kg moving with a velocity of 1 m/s, 1 J = 1 kg m^2/s^2 and 4.184 J = 1 cal

Question 18

kinetic energy

Answer 18

energy of a moving body, in joules, equal to 0.5mv^2

Question 18

nutritional calorie (Calorie)

Answer 18

unit used for quantifying energy provided by digestion of foods, defined as 1 kcal

Question 19

potential energy

Answer 19

energy of a particle or system of particles derived from relative position, composition, or condition

Question 19

specific heat capacity (c)

Answer 19

intensive property of a substance that represents the quantity of heat required to raise the temperature of 1 g of the substance by 1 degree C (1 K)

Question 20

standard enthalpy of combustion (delta Hc^o)

Answer 20

heat released when 1 mole of a compound undergoes complete combustion under standard conditions

Question 20

standard enthalpy of formation (delta Hf^o)

Answer 20

enthalpy change of a chemical reaction in which 1 mole of a pure substance is formed from its elements in their most stable states under standard state conditions

Question 21

standard state

Answer 21

set of physical conditions as accepted as common reference conditions for reporting thermodynamic properties; 1 bar of pressure, and solutions at 1 M, usually at a temperature of 298.15 K

Question 22

state function

Answer 22

property depending only on the state of a system, and not the path taken to reach that state

Question 22

surroundings

Answer 22

all matter other than the system being studied

Question 23

system

Answer 23

portion of matter undergoing a chemical or physical change being studied

Question 24

temperature

Answer 24

intensive property of matter that is a quantitative measure of “hotness” and “coldness”

Question 25

thermal energy

Answer 25

kinetic energy associated with the random motion of atoms and molecules

Question 26

thermochemistry

Answer 26

study of measuring the amount of heat absorbed or released during a chemical reaction or a physical change

Question 27

work (w)

Answer 27

energy transfer due to changes in external, macroscopic variables such as pressure and volume; or causing matter to move against an opposing force