Chapter 10: Chemical Analysis

Question 1

What is a formulation?

Answer 1

They are mixtures with a precise purpose that are made by following a ‘formula’. Each component in a formulation is present in a measured quantity and contributes to the specific properties of the formulation.

Question 2

What is purity in the normal world and in scientific terms?

Answer 2

Purity could be something that has had nothing added to it so its in its natural state for example beeswax or pure milk
In scientific terms purity is if something contains only one type of element or compound throughout

Question 3

What does the melting and boiling point tell you about how pure a substance is ?

Answer 3

A chemically pure substance will melt and boil at specific temperatures. If you want to see the purity of a substance boil it if the boiling point is not the precise documented number then it is impure in some way, the further away it is the more impure

Question 4

What are the two phases called in chromatography?

Answer 4

Mobile phase- where the molecules can move

Stationary phase- where the molecules cant move

Question 5

In paper chromatography how many spots will a pure substance form?

Answer 5

1

Question 6

What is the formula for the Rf value?

Answer 6

Distance travelled by substance/ distance travelled by solvent

Question 7

What is the name of the result of a chromatography test?

Answer 7

Chromatogram

Question 8

Describe the process of paper chromotgraphy

Answer 8

1) Line on paper 2cm from bottom in pencil
2) Fill beaker 1cm of water
3) Drip the substance(s) that are being tested onto pencil line
4) Attach paper to splint so it can hang into the beaker just touching water
5) Allow the water the move up the paper, separating the mix as it moves
6) Remove after no more chemical separation
7) Work out Rf by solvent travelled/substance travelled

Question 9

What is the test for chlorine gas?

Answer 9

Chlorine bleaches damp litmus paper, turning it white

Question 10

What is the test for Oxygen?

Answer 10

Putting a glowing splint into an area of concentrated oxygen will relight the splint

Question 11

What is the test for Carbon dioxide?

Answer 11

Bubbling carbon dioxide through limewater turns it cloudy

Question 12

What is the test for hydrogen?

Answer 12

Hold a lit splint at the end of a test tube containing hydrogen, you get a pop when the bung is removed