Chemical Analysis

Question 1

What is a pure substance

Answer 1

• something that only contains one compound or element throughout
• not mixed with anything else

Question 2

How can you see impurities from melting + boiling points

Answer 2

• impurities will lower the expected melting point and increase the melting range of your substance

Question 3

What are formulations

Answer 3

• useful 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 properties of the formulation so that it meets its required function

Question 4

Formulations of paints

Answer 4

• pigment: gives paint colour
• solvent: used o dissolve the other components and alter the viscosity
• binder (resin): forms a film that hold the pigment in place after its been painted on
• additives: added to further change the physical and chemical properties of the paint

Question 5

Why are formulations really important

Answer 5

• pharmaceutical industry
• by altering the formulation of a pill, chemists an make sure it delivers the drug to the correct part of the body at the right concentration, that it’s consumable and has a long enough shelf life life

Question 6

Where can formulations be seen in everyday life

Answer 6

• cleaning products
• fuels
• cosmetics
• fertilisers
• meta alloys
• food and drink

Question 7

2 phases of phases chromatography

Answer 7

• mobile phase
• stationary phase

Question 8

Mobile phase

Answer 8

• where molecules can move
• this is always a liquid or a gas

Question 9

Stationary phase

Answer 9

• where the molecules cant move
• this can be a solid or a really thick liquid

Question 10

What would a pure substances look like in a paper chromatography graph

Answer 10

• will only form 1 spot in any solvent as there is only one substance in the sample

Question 11

Stationary phase in chromatography

Answer 11

• the chromatography paper

Question 12

Mobile phase in chromatography

Answer 12

• solvent

Question 13

What does amount of time the molecules spend in each phase of chromatography depend on

Answer 13

• how soluble they are in he solvent
• how attracted the are to the paper
• molecules with a higher solubility in the solvent and les attraction to paper will spend moe time in the mobile phase and carried further up the paper

Question 14

Rf equation

Answer 14

Distance traveled by substance/ distance traveled by solvent

Question 15

Test for chlorine

Answer 15

• chlorine bleaches damp litmus paper, turning it white

Question 16

Test for oxygen

Answer 16

• if you put a glowing splint inside a test tube containing oxygen, the oxygen will relight the glowing splint

Question 17

Test for carbon dioxide

Answer 17

• bubbling carbon dioxide through an aqueous solution of calcium hydroxide (lime water) causes the solution to turn cloudy

Question 18

Test for hydrogen

Answer 18

• if you hold a lit splint at the open end of a test tube containing hydrogen, you’ll get a squeaky pop