chapter 4 separation techniques

Question 1

Where should the thermometer be placed when carrying out a fractional and simple distillation?

Answer 1

The bulb of the thermometer should be placed just beside the side arm leading from to the condenser

Question 2

When carry out simple and fractional distillation on volatile liquids what are some measurements that should be carried out to prevent them from evaporating?

Answer 2

The receiver should be placed on ice to keep the volatile liquids in liquid state

Question 3

What are the safety precautions when carrying out a chromatogram?

Answer 3

1. should not be tasting or smelling any of the chemicals
2. safety goggles should be worn
3. make sure that at the end of the experiments, the chemicals are safely disposed of

Question 4

definition of fractional distillation and least some examples

Answer 4

fractional distillation is different from simple distillation as it makes use of a fractionating column. Fractionating distillation separates miscible liquids with different boiling points

1. ethanol ( 78 ) and water ( 100 )
2. liquid air
3. crude oil ( which is a compound which consists of kerosene which is flammable, diesel oil, naphthene and gasoline )

Question 5

definition of simple distillation
and least some examples

Answer 5

simple distillation separates pure solvent ( liquids ) from its solution

1. separating seawater to get pure water
2. salt solution
3. sugar solution

Question 6

definition of filtration and least some examples

Answer 6

filtration is used to separate insoluble particles from their liquid

1. chalk and water
2. sand and water
3. clay and water

Question 7

what are the precautions when using a chromatogram?

Answer 7

1. The start line should be drawn using a pencil as it is not soluble in the solvent whereas pen ink is soluble in the solvent
2. the start line should be placed above the solvent
   so that the the chromatogram does not dissolve

Question 8

why are boiling chips placed in the distillate flask?

Answer 8

To smoothen boiling process, prevents the distillate from shaking to much and the solution from spilling out

Question 9

what is the use of a condenser and what are the conditions/

Answer 9

A condenser provides a cooler surface area for the vapor to lose heat and condense into liquid. The condenser should be sloping downwards as these would allow the liquid to drip downwards into the conical flask. Cold water goes in from the bottom of the condenser and comes out as warm water from the top of the condenser, this ensures an efficient cooling system. ( due to gravity )

Question 10

Why should the filter paper be wet with water before carrying out filtration where the separating of insoluble substances take place?

Answer 10

Since the filter paper is made out of a absorbent material, it would absorb the filtrate. Therefore the filter paper should be wet to avoid the filtrate from getting absorbed by the filter paper getting more of the filtrate

Question 11

Advantages of using a chromatogram?

Answer 11

The advantages of chromatogram is that it only requires a small sample of the substances, able to detect small quantities of impurities ( sensitive ),the process is fast