U2 AOS2 Chapter 12

Question 1

dilution

Answer 1

process of decreasing concentration of a solution by adding more solvent

Question 2

Molarity

Answer 2

concentration unit, mol/L

Question 3

what does concentration depend on?

Answer 3

ratio of solute to volume, not solely number of solute particles

Question 4

concentration formula

Answer 4

c = n/V

Question 5

real world application of concentration

Answer 5

liquid medications must specify concentration of active ingredients (in g/L or mg/L

Question 6

real world application of ppb and ppm

Answer 6

detecting active concentrations of ingredients in drugs, measuring greenhouse gas levels

Question 7

ppm units

Answer 7

= 1mg/kg or 1mg/L

Question 8

percentage calculations

Answer 8

solute to solution concentration (same units in calculation except for m/v)

Question 9

% (m/v) calculation

Answer 9

c=m(g)/v(ml) x 100%

Question 10

dilution equation

Answer 10

C1 x V1 = C2 x V2

Question 11

alum

Answer 11

inorganic chemical compound composed of hydrated aluminium salt, used to treat water by reducing concentration of phosphate

Question 12

crystalisation

Answer 12

process where solute molecules leave solution to form a highly organised crystal structure

Question 13

eutrophication

Answer 13

excessive algal growth due to increased nutrient concentration

Question 14

solubility curve

Answer 14

plots solubility vs temperature

Question 15

solubility trends solid/liquid solutes

Answer 15

as temp increases, solubility increases

Question 16

solubility trends gaseous solutes

Answer 16

as temp increases, solubility decreases

Question 17

benefits/uses of solubility curves

Answer 17

1. provide a visualisation of solubility at a given temperature
2. display trend in solubility of a single solute as temp changes
3. displays whether solution is supersaturated/unsaturated at a given temp (under/over the line)

Question 18

disadvantage of solubility curve

Answer 18

does not show the affect of temp on solubility

Question 19

applications of solubility curves

Answer 19

used in pharmaceutical industry to determine temp a reaction should take place/ determine point a solution becomes supersaturated

Question 20

affects of eutrophication

Answer 20

excess algae, deteriorates water quality = depletes amount of dissolved oxygen

Question 21

cause of eutrophication

Answer 21

phosphate from: human/animal waste, cleaning/waste water, industrial sewerage, fertiliser runoff

Question 22

process of using alum for eutrophication

Answer 22

1. reacts w/ water to form aluminium hydroxide (alum + H2O -> Al(OH)3)
2. phosphate reacts with Al(OH)3 to form aluminium phosphate precipitate (Al(OH)3 + PO43- -> AlPO4 + 3OH-)
3. Precipitate settles, no longer contributes to eutrophication

Question 23

solubility

Answer 23

the extent to which a solute is able to dissolve in a solvent

Question 24

when does the formation of crystals occur?

Answer 24

when a supersaturated solution is disturbed or a saturated solution is cooled

Question 25

effect of decreasing temp on solids/liquids

Answer 25

decreases solubility

Question 26

g to mg conversion

Answer 26

x 1000

Question 27

mg to microgram conversion

Answer 27

x 1000

Question 28

kg/L to kg/ML

Answer 28

x 1,000,000

Question 29

why do gases decrease in solubility as the temperature increases?

Answer 29

gas molecules have more kinetic energy, gas can move around and escape solution = solubility decreases

Question 30

what effect does decreased pressure have on the solubility of gases?

explain

Answer 30

more gas dissolves when pressure is higher, smaller amount of pressure = lower solubility

Question 31

factors affecting solubility (solids and liquids)

Answer 31

• temp (higher temp = higher solubility),
• ion charge (higher charge = lower solubility)
• ion size (larger ion = higher solubility)