AP Chem - Chapter 6 - Energy

Question 1

what is the law of conservation of energy

Answer 1

energy cannot be created nor destroyed

Question 2

what is energy

Answer 2

for our purposes, the capacity to produce heat

Question 3

what is heat

Answer 3

the transfer of energy

Question 4

what is temperature

Answer 4

a measure of kinetic energy

Question 5

what is the relationship between temperature and kinetic energy

Answer 5

directly proportional

Question 6

what is a state function

Answer 6

refers to a property of the system that depends only on its present state. a change in this function in going from one state to another state is independent of the particular pathway taken between the two states

Question 7

is energy a state function

Answer 7

yes

Question 8

is wrok a state function

Answer 8

no

Question 9

is heat a state function

Answer 9

no

Question 10

what is endothermic

Answer 10

refers to a reaction where energy (as heat) flows into the system

Question 11

what is exothermic

Answer 11

refers to a reaction where energy (as heat) flows out of the system

Question 12

if a reaction has a negative change in H, it is

Answer 12

exothermic

Question 13

if a reaction has a positive change in H, it is

Answer 13

endothermic

Question 14

energy released is

Answer 14

exothermic

Question 15

energy absorbed is

Answer 15

endothermic

Question 16

what is a calorimeter

Answer 16

a device used experimentally to determine the heat associated with a reaction

Question 17

what does q stand for

Answer 17

heat

Question 18

what is specific heat capacity

Answer 18

the amount of energy needed to raise the temp of 1 g of a substance by 1 degree C

Question 19

what are the units for specific heat capacity

Answer 19

J/degree C x g

Question 20

is the heat of reaction/change in enthalpy intensive or extensive

Answer 20

extensive

Question 21

is temperature intensive or extensive

Answer 21

intensive

Question 22

is change in enthalpy a state function

Answer 22

yes

Question 23

what is Hess’s law

Answer 23

in going from a particular set of reactants to a particular set of products, the change in enthalpy is the same whether the reaction takes place in one step or a series of steps

Question 24

what happens to the change of H if a reaction is reversed

Answer 24

the sign of change of H is reversed

Question 25

what do you do to the value of the change of H if the coefficients in a balanced equation are multiplied by an integer

Answer 25

multiply the change of H by the same integer

Question 26

what is standard enthalpy of formation

Answer 26

the change in enthalpy that accompanies the formation of one mole of a compound from its elements with all substances in their standard states

Question 27

what are “standard state” temperature and pressure

Answer 27

25 degrees celcius

1 atm

Question 28

what is the standard state concentration for a substance in a solution

Answer 28

1 M

Question 29

how do you find the change in enthalpy for a given reaction using standard enthalpies of formation

Answer 29

using the chart, add the standard enthalpies of formation pf the reactants and of the products (elements are not included; they’re 0). Then multiply each SEF by the amount of moles you have of it. Then subtract what you get for the products from what you got for the reactants.