Chemical Analysis

Question 1

How to measure if substance pure or not

Answer 1

Measure it’s boiling point
= pure substance melts at specific fixed temperature
= also has specific fixed boiling point
= impure melt and boil over range of temperatures

Question 2

Describe a formulation

Answer 2

Complex mixture that has been designed for a useful product
= Quantity of each component is carefully measured so that product has properties we need
= eg fuels, paints, alloys

Question 3

Paper chromatography function

Answer 3

To separate substances based on their different solubilities

Question 4

Phases of paper chromatography

Answer 4

• paper is the stationary phase
  = doesn’t move
• solvent is the mobile phases
  = it does move

Question 5

Product of pure compound

Answer 5

Produce a single spot in all solvents

Question 6

Products of a mixture

Answer 6

Compounds will separate into different spots depending on the solvent

Question 7

How far does soluble go on paper

Answer 7

The more soluble the higher up, it goes on the paper

Question 8

Why do we draw starting line with a different pencil

Answer 8

If we drew in pen the ink would move up the paper with the solvent

Question 9

Adv of chromatography

Answer 9

Can use to find an unknown substance

Question 10

How to find unknown chemical

Answer 10

• place dot of chemical onto pencil line
• place bottom of paper into a solvent
• if only one spot chemical is pure
• measure distance moved of chemical and solvent
• calculate rf value of substance

Question 11

Volume equation

Answer 11

Volume= moles X 24

Question 12

Why should water not be used as solvent

Answer 12

Colours won’t move or dissolve