C12 - experiential techniques & chemical analysis (Physical, chemical and separation techniques)

Question 1

define physical change

Answer 1

involves a change in substance’s form

Question 2

define chemical change

Answer 2

involves making a new substance and change in energy

Question 3

what measures time and units

Answer 3

-stop watch
-seconds

Question 4

what measures temperature and units

Answer 4

-thermometer
-degrees Celsius

Question 5

what measures mass and units

Answer 5

-mass balance
-grams

Question 6

what measures volume in liquid and units-1

Answer 6

-burette
-cm^3

Question 7

what measures volume in liquid and units- 2

Answer 7

-volumetric pipette
-cm^3

Question 8

what measures volume in liquid and gas and units

Answer 8

-measuring cylinder
-cm^3

Question 9

what measures volume in gas and units

Answer 9

-GAS syringe
-cm^3

Question 10

define pure

Answer 10

a substance that contains a single element or compound, not mixed with any other substances

Question 11

define impure

Answer 11

a substance that contains more than 1 element or compound, mixed with other substances

Question 12

define solvent

Answer 12

substance that dissolves a solute

Question 13

define solute

Answer 13

a substance that is dissolves in a solvent

Question 14

define solution

Answer 14

mixture that is made up of 1 or more substances

Question 15

define mixture

Answer 15

contains 2 or more substances not chemically combined

Question 16

define votality

Answer 16

how easily a substance evaporates (changes from liquid to gas)

Question 17

define solubility

Answer 17

how easily a substance dissolves

Question 18

is a solution a new product

Answer 18

no

Question 19

define saturated solution

Answer 19

solution containing maximum concentration of a solute dissolved in a solvent at a given temp.
(no more solute can dissolve in it)

Question 20

opposite of saturated

Answer 20

diluted

Question 21

define residue

Answer 21

a substance that remains after distillation, evaporation or filtration

Question 22

define crystallisation

Answer 22

when a liquids that contains soluble solute is evaporated to leave the soluble solute behind

Question 23

define filtrate

Answer 23

solution at pass through a filter paper

Question 24

explain diluted, concentrated, saturated

Answer 24

diluted:
-little solute
concentrated:
-moderate solute
saturated:
-max solute

Question 25

what must the solute be for filtration and why

Answer 25

insoluble so it's too big to pass through the holes in the filter paper

Question 26

names 6 separation techniques

Answer 26

-simple distillation -fractional distillation -filtration -evaporation -crystallisation -chromatography

Question 27

define evaporation

Answer 27

turning the liquid into gas to be lost from the substance using heat

Question 28

define filtration

Answer 28

passing solution over a filter paper and collecting the filtrate

Question 29

define immiscible and miscible

Answer 29

-immiscible- liquids that don't mix -miscible- liquids that mix

Question 30

how to get -insoluble solute from mixture of soluble and insoluble solute/ solution with insoluble solute

Answer 30

filtration

Question 31

how to get solute (soluble or insoluble) from solution

Answer 31

evaporation

Question 32

how to separate 2 immiscible liquids

Answer 32

separating funnel

Question 33

how to -at least 2 miscible liquids -solutions with liquids that have close boiling points to each other

Answer 33

-fractional distillation

Question 34

how to get solvent from soluble solute

Answer 34

-simple distillation

Question 35

how to separate 2 or more soluble solutes

Answer 35

-paper chromatography

Question 36

why does filtrations work to separate insoluble solute from solute

Answer 36

insoluble solute cannot pass through filter paper and is left as an residue. soluble solutes can pass through the paper

Question 37

why does evaporation work to get a solute from a solution

Answer 37

the solvent must have a lower boiling point than the solute

Question 38

why does a separating funnel work to separate 2 immiscible liquids

Answer 38

-there is a difference in density

Question 39

why does fractional distillation work to separate 2 miscible liquids

Answer 39

there is a difference in boiling points between the liquids

Question 40

why does simple distillation work to separate solvent from solute

Answer 40

there is a difference in boiling points between solvent and solute

Question 41

define chromatography

Answer 41

method of separating mixtures of soluble substances

Question 42

define stationary phase

Answer 42

the paper in paper chromatography

Question 43

define a chromatogram

Answer 43

result of separating the components of a mixture by chromatography

Question 43

define the mobile phase

Answer 43

solvent in paper chromatography

Question 44

define Rf value

Answer 44

retention factor

Question 45

formula for Rf value

Answer 45

distance travelled by substance ------------------------------------------------- distance of travelled by solvent (solvent front) (in decimal)

Question 46

define solvent front

Answer 46

-furthest point the solvent travels -for calculating Rf value

Question 47

define baseline

Answer 47

line that is drawn in an insoluble substance and where the inks are placed

Question 48

meaning of composition

Answer 48

what it's made up of

Question 49

the more it's attracted to stationary phase, the ?

Answer 49

closer it is to baseline

Question 50

the more soluble, the ?

Answer 50

further it travels up the paper

Question 51

how much must the solvent be

Answer 51

below the baseline but touches the paper

Question 52

what is the baseline drawn in and why

Answer 52

-pencil -it is insoluble so it doesn't travel up the paper

Question 53

where do you measure how far the solute travelled

Answer 53

the middle of the spot

Question 54

what happens if the solvent is above the baseline

Answer 54

solutes will just dissolve in liquid and not move up

Question 55

where is the water put from in the condenser of distillation

Answer 55

the lower part down the condenser

Question 56

3 ways purity of a substance can be assessed

Answer 56

-melting point -boiling point -chromatography

Question 57

what does impurities do

Answer 57

-lower melting point -increase boiling point (melts over a greater range)

Question 58

what is the difference between melting and boiling points of pure and impure substances

Answer 58

pure- has a sharp melting/ boiling point impure- melts/ boils over a range

Question 59

how many spots will a pure and impure substance have on chromatography

Answer 59

pure- 1 impure- more than 1

Question 60

describe how to obtain a pure dry sample of a substance from a chromatogram

Answer 60

-isolate substance -dissolve in solvent -evaporate solvent

Question 61

note: learn how to draw apparatuses

Question 62

do permanent markers work for chromatography

Answer 62

no, it's insoluble

Question 63

-substance melts at 96 but melts completely at 113. -date book says melting point of substance is 116. -explain is substance is impure or not

Answer 63

-impure -melts over a range -melting point is different to data book value.

Question 64

describe how to get a pure dry sample of a compound from a chromatogram

Answer 64

-isolate the substance -dissolve the compound in a solvent -evaporate the solvent

Question 65

explain if a substance is impure or pure

Answer 65

-range it melts over -different from data book value

Question 66

2 processes to obtain pure sodium chloride from mixture with insoluble sulfer and sodium chloride in water

Answer 66

filtration and crystaillisation

Question 67

2 processes to separate water from insoluble chalk and soluble salt

Answer 67

filtration and crystalisation

Question 67

apparatus to measure volume of gas

Answer 67

gas syringe

Question 68

-colorings S,T and U are -soluble -use chromatography in candy to find them measurements?

Answer 68

-height of each spot and height of solvent front -compare Rf values of colourings and candy

Question 68

-colorings S,T and U are -soluble -use chromatography in candy to find them method?

Answer 68

-crush candy and dissolve in solvent -pencil line on paper -add each colours and sweet solution to paper -remove paper before solvent reaches the top -mark solvent line and find Rf value

Question 69

-colorings S,T and U are -soluble -use chromatography in candy to find them use of results?

Answer 69

-if candy spots are same height up paper as S, T, S, then substances are in the candy -if same ratio of spot distance to solvent front distance (Rf value), substance is in candy