Chemistry - Chapter 17

Question 1

Thermochemistry

Answer 1

the study of energy changes that occur during chemical reactions and changes in state

Question 2

Chemical Potential Energy

Answer 2

The energy stored in the chemical bonds of a substance

Question 3

Heat

Answer 3

(q), energy that transfers from one object to another because of temperature difference between the objects

Question 4

System

Answer 4

part of the universe on which you focus your attention

Question 5

Surroundings

Answer 5

everything else in the universe

Question 6

Law of Conservation of Energy

Answer 6

states that in any chemical or physical process, energy is neither created nor destroyed

Question 7

Endothermic Process

positive or negative value?

Answer 7

heat is absorbed from the surroundings

Heat flowing into a system from its surroundings = positive

Question 8

Exothermic Process

positive or negative value?

Answer 8

one that releases heat to its surroundings

Heat flowing out of a system into its surroundings = Negative

Question 9

Specific Heat

what else is this called?

Answer 9

amount of heat it takes to raise the temp. of 1g of the substance 1° C

Specific Heat Capacity

Question 10

Calorimetry

Answer 10

measurement of the heat flow into or out of a system for chemical and physical processes

Question 11

calorimeter

Answer 11

the insulated device used to measure the absorption or release of heat in chemical or physical processes

Question 12

enthalpy (H)

Answer 12

accounts for the heat flow of the system at constant pressure

Question 13

molar heat of fusion

Answer 13

heat absorbed by 1 mole of a solid substance as it melts to a liquid at constant temp.

S –> L

Question 14

molar heat of solidification

Answer 14

the heat lost when 1 mole of a liquid substance solidifies at a constant temp.

L –> S

Question 15

molar heat of vaporization

Answer 15

amount of heat required to vaporize 1 mole of a given liquid at constant temp.

L –> G

Question 16

molar heat of condensation

Answer 16

the amount of heat released when 1 mole of vapor condenses at its normal boiling point

G –> L

Question 17

molar heat of solution

Answer 17

the enthalpy change caused by the dissolution of 1 mole of substance

Question 18

Calorie conversions (3)

Answer 18

1 Calorie = 1 Kilocalorie = 1000 calories

Question 19

Calorie

Answer 19

quantity of heat needed to raise the temperature of 1g of pure water at 1°C

Question 20

Joule conversions (2)

Answer 20

1 J = 0.2390 cal

1 cal = 4.184 J

Question 21

Energy

Answer 21

capacity for doing work or producing heat

Question 22

Specific Heat formula

Label the variables (4)

Answer 22

C = [q / (m x ΔT)]

C = specific heat 
q = heat (J)
m = mass (g)
ΔT = Tf-Ti

Question 23

How to calculate the heat absorbed / released by the surroundings

Label Variables (2)

Answer 23

qsurr = m x C x ΔT

m = mass of water (g)
C = specific heat of water (J/(g°C)

Question 24

How to calculate the heat absorbed / released by the system

Label Variables (2)

Answer 24

qsys = ΔH = -qsurr = -m x C x ΔT

-m = -mass of water (g) 
C = specific heat of water

Question 25

heat capacity

Answer 25

the amount of heat needed to increase the temperature of an object exactly 1°C

Question 26

Thermochemical Equation

Answer 26

a chemical equation that includes the enthalpy change (ΔH)

ex. CaO(s) + H2O(l) –> Ca(OH)2(s) + 65.2kJ

Question 27

Heat of Reaction

Answer 27

the enthalpy (ΔH) change for a chemical equation exactly as it is written

ex. ΔH = -65.2 kj = heat of reaction

Question 28

Heat of Combustion

Answer 28

The heat of reaction for the complete burning of 1 mole of a substance

ex. CH4(g) + 2O2(g) —> CO2(g) + 2H2O(l) + 890kJ or
CH4(g) + 2O2(g) —> CO2(g) + 2H20(l) ΔH = -890kJ

Question 29

units for the molar heat of…

Answer 29

kJ / mol

Question 29

What does energy lack? (2)

Answer 29

A mass or volume

Question 30

How is energy detected?

Answer 30

By its effects

Question 31

What determines the amount of energy stored in a substance?

Answer 31

The kind of atoms and the arrangement of the atoms in a substance

Question 32

How does heat flow?

Answer 32

From the warmer object to the colder object

Question 33

Heat capacity depends on….(2)

Answer 33

Mass and chemical composition

Question 34

What has a high specific heat? Low specific heat?

Answer 34

High - water

Low - metals