26:Practical Chemistry

Question 1

What is a standard solution

Answer 1

A solution whose concentration is accurately known

Question 2

How to prepare a standard solution

Answer 2

(i) Calculate the mass of solute needed to make the required volume (eg 250 cm³) of solution.
(ii) Weigh this amount accurately using an electronic balance.
(iii) Dissolve this material in a limited amount of distilledwater, in a beaker.
(iv) Transfer this solution to a volumetric flask. Wash any remaining solution from the beaker into the flask with distilled water. Then make the volume up to the mark (eg 250 cm³) by adding more distilled water.
(v) Invert the flask several times to mix the solution thoroughly.

Question 3

What is a burrete measured to

Answer 3

to the nearest 0.05cm³

Question 4

What is the equation for percentage error

Answer 4

%error = (maximum error / value measured) x100

Question 5

What apparatus is used in titration

Answer 5

Burette, Conical flask, pipette, clamp

Question 6

Where should the meniscus be relative to the line you are trying to measure

Answer 6

Should be ontop of the line

lowest point of liquid is ontop of the line

Question 7

What apparatus is used in thermal decomposition experiments

Answer 7

Bunsen Burner, tripod, heatproof mat, crucible and lid, pipeclay triangle

Question 8

How can you tell if thermal decomposition is finished

Answer 8

When the mass doesn’t change after more heating

Question 9

Describe the apparatus setup used in reflux

Answer 9

A round bottom flask with a condenser on top being heated from the bottom (by a Bunsen burner or waterbath and heater)

Question 10

How can insoluble organic liquids be separated from water

Answer 10

A separating funnel

Question 11

3 methods of purifying organic liquids

Answer 11

Separating funnel,

Drying,

Distillation

Question 12

Describe the apparatus used in distillation

Answer 12

Round bottom flask connected to condenser that goes into a beaker. Heat source under the flask. Thermometer in the flask.