2.1

Question 1

Solutions: what are mixtures?

Answer 1

• most natural substances
• have variable composition
• retain component properties

Question 2

what is a solution?

Answer 2

• homogenous mixture (uniform distribution) of 2 or more substances in A SINGLE PHASE

Question 3

Gas and solid solutions what happens?

Answer 3

• gases completely miscible (be able to mix)

- gas dissolved in solid: occupies spaces in solid lattice eg. H2 in Pd

Question 4

What is an alloy?

Answer 4

solid solution of metals ( a metal made by combining 2 or more metallic element)

Question 5

true or false: substances with similar types of intermolecular forces will dissolve in each other

Answer 5

true

Question 6

The solution process: what are the factors which determine whether a substance dissolves

Answer 6

enthalpy- exothermic favors dissolving

entropy- always favors solution formation ( solutions form naturally; not pure substances)

Question 7

true or false: energy required to separate particles

Answer 7

true

Question 8

true or false: energy released when particles mixed and new attractions form

Answer 8

true

Question 9

What does delta H soln stand for?

Answer 9

Heat of solution: it = the total enthalpy change when solution forms from pure solvent and pure solute

Question 10

What does forming a solution involve?

Answer 10

1. ) solute particles separate - endothermic
2. ) solvent particles separate - endothermic
3. ) solute + solvent particles mix - exothermic

Question 11

express delta H solution = ….

overall enthalpy change - reflection of strength of intermolecular attractions

Answer 11

delta H solution = delta H solvent + delta H solute + delta H mixture

Question 12

What are the heats of solution measured by?

Answer 12

calorimeter

Question 13

true or false: When the delta H solution is highly positive, it is likely that the solute is highly insoluble

Answer 13

true

Question 14

What does hydration mean?

Answer 14

solvation in water

Question 15

true or false: solvation of ions in water is always exothermic

Answer 15

true

Question 16

delta H hydration =….

Answer 16

delta H h20solvent + delta H mix

Question 17

what is delta H hydration related to?

Answer 17

• charge density of ion

- distance between ion and dipole

Question 18

why does the higher the charge the more negative the delta H of hydration?

Answer 18

water molecules can experience a greater magnitude and attraction to ion

Question 19

why does the smaller the ion the more negative the delta H of hydration

Answer 19

the closer the ions can come to the water

Question 20

What does lattice energy mean?

Answer 20

it is the amount of energy required to separate a solid ionic compound into GASEOUS IONS

Question 21

express delta H solution when ionic compound is dissolved in water

Answer 21

delta H soln = delta H solute + delta H hydration

Question 22

define solubility

Answer 22

maximum amount of solute THAT WILL dissolve in a solvent at a certain temperature

Question 23

What are solutions classified as?

Answer 23

saturated and supersaturated

Question 24

Define saturated

Answer 24

contains maximum quantity of dissolved solute in presence of solid( at that temperature) ; if we add anymore will not dissolve anything

Question 25

define super saturated

Answer 25

contains more solute than equilibrium amount of solute dissolved is unstable

Question 26

what happens to solutions at equilibrium?

Answer 26

for solid in solution with time: | rate of dissolving = rate of crystallization

Question 27

What are the factors which affect rate of dissolution | solvent molecules must make contact with solute

Answer 27

rate of dissolution increased by: - increasing surface area of solute (also stirring) - increase temperature

Question 28

definition of dissolution

Answer 28

is the process in which a solute forms a solution in a solvent

Question 29

true of false: most ionic solids are more soluble at higher solvent temperatures

Answer 29

true

Question 30

Does increasing the temperature usually increase the amount of solute that dissolves to give a saturated solution

Answer 30

yes

Question 31

what does henry's law state

Answer 31

that the solubility of gas in liquid is proportional to gas pressure

Question 32

Express henry's law

Answer 32

Sg= KhPg

Question 33

what does Sg mean?

Answer 33

solubility of gas in liquid (mol L-1)

Question 34

what does Kh mean?

Answer 34

henry's constant (mol L-1 atm-1)

Question 35

what does Pg mean?

Answer 35

partial pressure of gas above solution (atm)

Question 36

the relationship of temperature and solubility

Answer 36

as solvent temperature increases, gas solubility decreases | think of cold water