Measurement and Experimental Techniques

Question 1

Unit for Mass

Answer 1

kg

Question 2

Unit for Time

Answer 2

s

Question 3

Unit for temperature

Answer 3

degree celsius

Question 4

How to collect gases? Suggest 2 methods.

Answer 4

Displacement of air
-upward delivery
-downward delivery
Displacement of water

Question 5

Displacement of water is suitable for

Answer 5

collecting gases that are insoluble/slightly soluble in water
e.g. CO2.H2.O2

Question 6

Downward delivery is suitable for

Answer 6

collect gas that are soluble in water and denser than air
e.g. chlorine and hcl

Question 7

Upward delivery is suitable for

Answer 7

gases soluble in water and less dense than air
E.G. NH3

Question 8

Drying gases, state 3 ways.

Answer 8

Quicklime, dry ammonia
Fused CaCl2
Concentrated H2SO4, dry most gases other than NH3

Question 9

what is a mixture?

Answer 9

substance made up of two or more substances not chemically combined

Question 10

what is a pure substance

Answer 10

made up of 1 single element or compound

Question 11

3 ways to test purity

Answer 11

melting point of solid
boiling point
chromatography

Question 12

what does impurities do to the melting point?

Answer 12

lowers melting pt & melt over range of temperature

Question 13

what does impurities do to boiling point?

Answer 13

increases boiling pt

Question 14

3 ways to separate solid liquid mixture

Answer 14

filtration
evaporation
crystallisation

Question 15

3 ways to separate solid solid mixture

Answer 15

sublimation
magnet
suitable solvent

Question 16

4 ways to separate liquid liquid mixture

Answer 16

distillation
separating funnel
paper chromatography
fractional distillation