Chapter 6 - Thermochemistry

Question 1

calorie

Answer 1

the amount of energy needed to raise the temperature of one gram of water one degree Celsius, 1 cal = 4.184 J

Question 2

calorimeter

Answer 2

a device used to determine the heat associated with a chemical or physical change

Question 3

calorimetry

Answer 3

the experimental determination of the enthalpy changes of reactions

Question 4

endothermic

Answer 4

a chemical reaction or physical change in which heat is absorbed by the system [q is positive]

Question 5

energy

Answer 5

the capacity to do work or transfer heat

Question 6

enthalpy

Answer 6

the sum of the internal energy of the system and the product of its pressure and volume

Question 7

enthalpy of reaction

Answer 7

the change in enthalpy for a reaction at a given temperature and pressure

Question 8

exothermic

Answer 8

a chemical reaction or physical change in which heat is evolved or is released from the system [q is negative]

Question 9

first law of thermodynamics

Answer 9

a law stating that the energy of the universe is constant, so the internal energy of a system is equal to the sum of heat and work exchanged between the system and surroundings

Question 10

heat

Answer 10

the flow of energy due to a temperature difference

Question 11

heat capacity

Answer 11

the quantity of heat needed to raise the temperature of a sample one degree Celsius

Question 12

Hess’s law

Answer 12

if a reaction is the sum of two or more other reactions, the enthalpy change for the overall process is the sum of the enthalpy changes for the constituent reactions

Question 13

internal energy

Answer 13

the sum of the potential and kinetic energies of the particles in the system

Question 14

joule

Answer 14

a unit of measurement for energy, 1 cal = 4.184 J

Question 15

kinetic energy

Answer 15

energy associated with the motion of an object

Question 16

law of conservation of energy

Answer 16

energy cannot be created or destroyed, only converted from one form to another

Question 17

potential energy

Answer 17

energy due to position or composition

Question 18

molar heat capacity

Answer 18

the quantity of heat needed to raise the temperature of one mole of a sample one degree Celsius

Question 19

specific heat capacity

Answer 19

the quantity of heat needed to raise the temperature of one gram of a sample one degree Celsius

Question 20

standard enthalpy of formation

Answer 20

the enthalpy change for the formation of one mole of a substance in its standard state from its elements in their reference forms and in their standard states

Question 21

standard state

Answer 21

the most stable form of a substance at standard thermodynamic conditions [1 atm and usually 25°C]

Question 22

state function / state property

Answer 22

a property that is independent of the pathway

Question 23

surroundings

Answer 23

everything outside the system in a thermodynamic process

Question 24

system

Answer 24

the substance[s] being evaluated for energy content in a thermodynamic process

Question 25

thermodynamics

Answer 25

the study of energy and its interconversions

Question 26

work

Answer 26

force acting over a distance