Ch. 7

Question 1

physical change is caused by what? what TD quantity is closely related to change

Answer 1

changes inintermolecular forces between molecules or atoms NOT INTRAMOLECULAR (molecules interacting with other molecules causes changes). Temp is related to change

Question 2

entropy does what as we go from solid to gas

Answer 2

solid: lowest KE and lowest entropy
liquid: medium
gas: highest KE and highest entropy

Question 3

solid to liquid is called

Answer 3

fusion or melting

Question 4

liquid to solid is called

Answer 4

crystallization or freezing

Question 5

liquid to gas is called

Answer 5

vaporization or boiling

Question 6

gas to liquid is called

Answer 6

condensation

Question 7

solid to gas is called

Answer 7

sublimation

Question 8

gas to solid is called

Answer 8

deposition

Question 9

as KE and S increases, heat is what?
as KE and S decreases, heat is what?

Answer 9

as it increases: absorbed
as it decreases: released

Question 10

what is heat of transtion

Answer 10

the amount of energy required to complete a transition “heat of fusion or heat of condensation, etc)

Question 11

amount of heat is dependent on

Answer 11

1. type of substance and 2. amount of substance

Question 12

what is calorie

Answer 12

amount of heat required to raise temp of 1 gram of water by 1 Celsius. 1 Cal=4.2 Joules

Question 13

when a substance absorbs or releases heat what will occur

Answer 13

it will change temp or undergo a phase change, both will not occur at same time.

Question 14

what is heat capacity

Answer 14

amount of HEAT to be supplied to an object to produce a unit change in its temperature, temp is inversely proportional to heat capacity

Question 15

what is specific heat

Answer 15

how resistant it is to change in temp, the amount of ENERGY needed to change temp

Question 16

what is a phase transition diagram?

Answer 16

a graph that states that as heat is added to a substance, its temp will rise until it reaches a transition state. once it hits a transition state, the energy inputting is towards changing transition until it finishes and raises temp to reach next transition state

Question 17

what two main things causes a phase change

Answer 17

temp and pressure

Question 18

what are boundary lines in the phase transition diagram?

Answer 18

when phases are in equilibrium

Question 19

at 1 atm, temp at this point is called

Answer 19

normal melting or boiling point at certain boundary lines

Question 20

what is the triple point

Answer 20

temp and pressure in which all 3 phases exist simultaneously at equilibrium

Question 21

what is critical point? what is the phase that occurs after this point?

Answer 21

a critical point marks end of liquid-gas boundary and it creates supercritical fluid that no matter how high pressure, it cant become a liquid. it has high density and low viscosity

Question 22

what makes water special in its phase changes

Answer 22

it is denser in liquid phase than its solid phase making the solid liquid boundary to have a (-) slope compared to (+) like most other molecules

Question 23

how can you tell if a compound has strong IMF

Answer 23

Ionic and polar covalent compounds because they are more EN and can interact with more molecules if they can h-bond

Question 24

if a compound that is both liquid and solid is at equilibrium, what combination of liquid and solid should have lowest temp?

Answer 24

all combinations have temp at 0 because its at equilibrium

Question 25

when H and q is positive , what is heat

Answer 25

absorbed

Question 26

when H and q is negative, what is heat

Answer 26

released

Question 27

1 calorie is what in joules

Answer 27

4.2

Question 28

which solid will exhibit the smallest change in temp? Al (0.9), Pb (0.1), or Sn (0.2) (numbers are specific heat)

Answer 28

Al because it has highest specific heat and temp and specific heat are inversely proportional.

Question 29

what is formula to find amount of heat needed for a phase change?

Answer 29

q=n x H where n is number of moles and H is heat of transition

Question 30

temp is proportional to

Answer 30

q heat added/released by a sample

Question 31

Measurement of Heat Changes (calorimetry) formula

Answer 31

q=mc(delta)T where m is mass, c is specific heat, and t is temp change

Question 32

from right to left, where are the phases on the phase diagram

Answer 32

solid (left top side), liquid (middle), and gas (right and bottom)

Question 33

waters melting/boiling point increases as pressure

Answer 33

decreases

Question 34

A chemical that has weak intermolecular forces will be volatile or non-volatile

Answer 34

Volatile. Chemicals that act as hydrogen donors and receptors have increased intermolecular forces, causing them to be less volatile.