C10

Question 1

Whta is a pure substance ?

Answer 1

A single element or compound , not mixed with any other substance

Question 2

What tells you the purity of the liquid?

Answer 2

Comparing the melting and boiling point of a substance and a pure substance.

Question 3

What state is Pure subtance in ?

Answer 3

A natural state

Question 4

What will happens to the melting point if the substance has impurities?

Answer 4

Lower the melting point and increase melting range of the substance.

Question 5

What happens to the boiling point if there are impurities in a substance?

Answer 5

Increase the boiling point and may result in a sample boiling at the end.

Question 6

What is a formulation?

Answer 6

A mixture that has been designed as a useful product. Each component is present in a measured quantity and contributes to the properties of the formulation so that it meets required function

Question 7

How are formulations made?

Answer 7

Mixing components in carefully measured quantities to ensure that the product has the required properties

Question 8

Examples of formulations?

Answer 8

Fuels
Cleaning agents
Paints 
Medicines
Alloys
Fertilisers
Foods

Question 9

Why formulations are important in the pharmaceutical industry ?

Answer 9

Altering formulation of a pill can make sure it delivers the drug to the correct part of the body at the right concentration.

Question 10

What and how do you test for hydrogen?

Answer 10

Uses a burning splint held at the open end of the test tube of the gas. Hydrogen burns rapidly with a pop sound

Question 11

How to test for oxygen

Answer 11

Use a glowing splint inserted into a test tube of gas. Splint relights in oxygen

Question 12

How to test for carbon dioxide and what happens ?

Answer 12

Use an aqueous solution of calcium hydroxide (lime water). When carbon dioxide is shaken with or bubbled through lime water the limewater turns milky(cloudy)

Question 13

How to test for chlorine and what happens?

Answer 13

Use litmus paper . When damp litmus paper is put into chlorine gas the litmus paper is bleached and turns white.

Question 14

What can chromatography do ?

Answer 14

Used to separate mixtures and can give information to help identify substances

Question 15

What is chromatography?

Answer 15

Involves a stationary phase and a mobile phase separation depends on the distribution of substances between phases

Question 16

What is chromatography?

Answer 16

An analytical method used to separate the substances in a mixture. You can use it to identify a substance. There are different types of chromatography , but they all have two phases?

Question 17

What is the mobile phase in chromatography?

Answer 17

Where molecules can move. This is always a liquid or a gas

Question 18

What is the stationary phase of chromatography?

Answer 18

Where molecules cant move . This can be a solid or thick liquids

Question 19

What happens to the phases during chromatography?

Answer 19

Constantly moving between phases , to meet an equilibrium

Question 20

What is the Rf value?

Answer 20

Ratio of the distance moved by a compound (centre of the spot from the origin) to the distance moved by the solvent can be expressed as this.

Question 21

Equation fo Rf?

Answer 21

Distance moved by a substance / distance moved by a solvent

Question 22

What can Rf help find?

Answer 22

Different compound shave different Rf values in different solvents, which can help identify the compounds.

Question 23

What happens to the compounds in the mixture?

Answer 23

May separate into different spots depending on the solvent but a pure compound will produce a single spot in all solvents

Question 24

What does the time spent in each phase depend on?

Answer 24

• how soluble they are in a solvent

- how attracted they are to paper