EXPERIMENTAL TECHNIQUES

Question 1

State the SI units of Time, Temperature, Mass, Volume [4]

Answer 1

-second(s)
-kelvin(K)
-kilogram(kg)
-cubic metre(m3)

Question 2

Apparatus used to measure TIME, TEMPERATURE, MASS [3]

Answer 2

-stopwatch
-thermometer
-electronic balance

Question 3

APPARATUS USED TO MEASURE VOLUME
1) approx volume
2) approx volume of larger quantities
3) measure volume of liquids 10.0cm3 or 25cm3
4) measure nearest 0.5cm3 of liquid
5) measure accurately nearest 0.05 cm3
6) measure volume of gases

Answer 3

1) BEAKER
2) VOLUMETRIC FLASK
3) PIPETTE (10cm3 or 25cm3)
4) MEASURING CYLINDER (nearest 0.5cm3)
5) BURETTE (nearest 0.05cm3)
6) GAS SYRINGE

Question 4

COLLECTION OF GAS:
1) collect gases NOT VERY SOLUBLE IN WATER such as OXYGEN & HYDROGEN
2) collect gases which are DENSER than air such as CARBON DIOXIDE, HYDROGEN CHLORIDE & CHLORINE
3) collect gases LESS dense than air such as AMMONIA & HYDROGEN

Answer 4

1) Displacement of water
2) Downward delivery
3) Upward delivery

Question 5

DRYING OF GAS:
1) dry gases which do not react with CALCIUM CHLORIDE
2) dry gases acidic gases such as CARBON DIOXIDE & CANNOT dry gases which are basic
3) dry basic gases such as AMMONIA & cannot dry gases which are acidic

Answer 5

1) FUSED CALCIUM CHLORIDE
2) CONCENTRATED SULPHURIC ACID
3) CALCIUM OXIDE

Question 6

Mg+H2SO4-> MgSO4 + H2
(a) describe using a method, including the apparatus needed, that can be used to find out how fast magnesium reacts with sulphuric acid
(b) how can the gas produced in the reaction be collected?

Answer 6

the volume of hydrogen gas can be measured at regular time intervals. To carry out this experiment, first prepare a conical flask containing sulphuric acid. Then, connect a gas syringe to the conical flask. Add the magnesium ribbon into the sulphuric acid and start measuring and recording the volume of hydrogen gas produced at regular time intervals until there is no further change. Lastly, plot a graph of volume of hydrogen gas produced against time.
Rate of reaction = volume of gas produced / time taken OR
Rate of reaction = decrease in mass of reaction mixture/time taken
(b) hydrogen gas can be collected using displacement of water