chapter 9

Question 1

If it has more energy, does it make it less or more stable?

Answer 1

less stable

Question 2

thermochemistry definition

Answer 2

absorption or release of heat energy that accompanies chemical reactions

Question 3

if it has less energy, is it more or less stable

Answer 3

it is more stable

Question 4

define energy

Answer 4

capacity to do work or supply heat (kinetic or potential)

Question 5

define joule

Answer 5

SI unit for energy

Question 6

What is kinetic energy

Answer 6

energy of motion

Question 7

What is potential energy

Answer 7

stored energy

Question 8

conservation of energy law

Answer 8

energy can’t be created or destroyed, only be converted into another form

Question 9

define temperature

Answer 9

thermal energy (kinetic) of molecular motion

Question 10

define heat

Answer 10

amount of thermal energy transferred from one object to another as a result in a temp difference between the two.

Question 11

what is the first law in thermodynamics

Answer 11

energy can’t be created or destroyed, only converted from one to another.

Question 12

define system

Answer 12

starting reactants and final products of the experiment

Question 13

define surroundings

Answer 13

everything but the system (EX: flask, solvent, room)

Question 14

define internal energy

Answer 14

sum of all kinetic and potential energies for every molecule, in the system of an isolated system

Question 15

is it possible to completely isolate a chemical reaction from its surroundings

Answer 15

no

Question 16

How do you calculate internal energy

Answer 16

energy final minus energy initial

Question 17

if energy flows from a system to its surroundings, is it positive or negative?

Answer 17

negative

Question 18

internal energy depends on what?

Answer 18

identity, pressure, size, state, temperature

Question 19

if energy flows from its surroundings to a system, is it positive or negative?

Answer 19

positive

Question 20

state function

Answer 20

property whose value depends only on present state, condition, not path to get there.

Question 21

energy content in food is measure in?

Answer 21

calories

Question 22

define work

Answer 22

fore that produced movement times distance the object moved.

Question 23

thermal chemical equation

Answer 23

chemical equation with enthalpy change

Question 24

what is enthalpy change

Answer 24

amount heat released or absorbed when reactants convert to products

Question 25

thermodynamic standard state

Answer 25

most stable form of a substance at 1 atm pressure and at a specified pressure, usually 25 degrees C, 1M concentration for all substances in a solution

Question 26

standard enthalpy of reaction

Answer 26

enthalpy change under standard conditions

Question 27

endothermic

Answer 27

reactions in which the system gains heat

Question 28

exothermic

Answer 28

reactions that lose heat to their surroundings

Question 29

enthalpy of fusion

Answer 29

amount of heat necessary to melt a substance without changing its temperature

Question 30

enthalpy of vaporization

Answer 30

amount of heat required to vaporize a substance without changing its temperature

Question 31

sublimation

Answer 31

the direct conversion of a solid to a vapor at atm pressure without first melting it to a liquid

Question 32

calorimeter

Answer 32

device that can measure amount of heat transferred during a reaction

Question 33

bomb calorimeter

Answer 33

measures heat released during combustion reaction or flammable substance

Question 34

heat capacity

Answer 34

amount of heat required to raise temperature of a substance

Question 35

extensive property

Answer 35

depends on size and amount

Question 36

specific heat

Answer 36

amount of heat necessary to raise the temperature of a given object

Question 37

molar heat capacity

Answer 37

amount of heat necessary to raise the temp of 1 mol by 1 degree Celsius

Question 38

hess’s law

Answer 38

the overall enthalpy for a reaction is equal to the sum to the enthalpy changes for the individual steps in the reaction

Question 39

standards heats of formation

Answer 39

the enthalpy changes for the formation of 1 mol in its standards state from its constituent elements in their standard states

Question 40

rules for standard heat of formation

Answer 40

often the reaction is hypothetical and must be in stable form

Question 41

define bond dissociation energy

Answer 41

amount of energy supplied to break a chemical bond