C2 Experimental techniques

Question 1

which piece of equipment is used to measure time and what are the units? (2)

Answer 1

stopwatch in seconds

Question 2

which piece of equipment is used to measure temperature and what are the units? (2)

Answer 2

thermometer in degrees Celsius

Question 3

which piece of equipment is used to measure mass and what are the units? (2)

Answer 3

mass balance in grams

Question 4

which 3 pieces of equipment are used to measure volume of a liquid and what are the units? (4)

Answer 4

measuring cylinder.
volumetric pipette.
burette.
in cm^3

Question 5

which piece of equipment is used to measure the volume of a gas and what are the units? (2)

Answer 5

gas syringe in cm^3

Question 6

how do you calculate Rf values in paper chromatography? (1)

Answer 6

distance moved by solute / distance moved by solvent

Question 7

define a pure substance (1)

Answer 7

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

Question 8

what process is used to separate two or more solid which are soluble? (1)

Answer 8

paper chromatography

Question 9

describe 3 ways that the purity of a substance can be assessed (3)

Answer 9

melting point.
boiling point.
chromatography.

Question 10

describe how melting point / boiling point can be used to assess purity (2)

Answer 10

a pure substance will have a sharp melting / boiling point.
an impure substance will melt over a temperature range.

Question 11

describe how chromatography can be used to assess purity (1)

Answer 11

a pure substance will produce only one well defined spot on a chromatogram

Question 12

describe two examples of where purity of a substance is important (2)

Answer 12

manufacture of compounds used in drugs and food additives

Question 13

what is solvent (1)

Answer 13

a substance that dissolves a solute

Question 14

what is solute (1)

Answer 14

a substance that is dissolved in a solvent

Question 15

what is solution (1)

Answer 15

a liquid mixture composed of two of more substances

Question 16

define volatility (1)

Answer 16

how easily a substance evaporates / changes from liquid to gas

Question 17

define solubility (1)

Answer 17

how easily a substance dissolves

Question 18

what is filtration used for (1)

Answer 18

to separate an insoluble solid from a liquid

Question 19

what is the filtrate in filtration (1)

Answer 19

the liquid or solution that has passed through the filter

Question 20

what is crystallisation (1)

Answer 20

when a liquid that contains a dissolved salt is evaporated to leave the salt behind

Question 21

what is distillation used for (1)

Answer 21

to separate a solvent from a solution

Question 22

what is the difference between immiscible and miscible liquids (2)

Answer 22

immiscable liquid doesn’t mix, while miscible liquid mix

Question 23

how can immiscible liquids be separated (1)

Answer 23

by using a separation funnel

Question 24

how can fractional distillation be used to separate miscible liquids / gases (1)

Answer 24

because the liquids / gases have different boiling points

Question 25

what is a residue in filtration (1)

Answer 25

a substance that remains after evaporation, distillation, filtration or similar processes