Higher Chemistry Full Course

Question 1

State what is meant by the term electronegativity.

Answer 1

Electronegativity is the measure of attraction an atom/nucleus has for the electrons in a bond/shared electrons.

Question 2

Explain why electronegativity values decrease going down group 7.

Answer 2

(More shells) so increased 1 shielding/more shielding.
OR
Covalent radius increases/atom size increases/more shells so attraction of the nucleus/protons for the (outer/shared) electrons decreases.

Question 3

Name a reagent which could be used to distinguish between

3-methybutanal and a ketone.

Answer 3

Fehling’s solution/ Tollen’s reagent/ acidified dichromate solution.

Question 4

Explain the decrease in atom size across the third period.

Answer 4

Increasing/greater/stronger/higher nuclear charge.

Question 5

Explain fully what can happen to 3-methyl Uta also that will cause the olive oil to develope an unpleasant taste.

Question 6

How do you know something is a condensation reaction?

Answer 6

Because it has two molecules joining together with the loss of a small/ water molecule.

Question 7

Write the molecular formula for retinol (Vitamin A)

Answer 7

C20H29OH
OR
C20H30O

Question 8

When terpineol is heated with Copper (II) oxide, no reaction takes place.

Explain why no reaction takes place.

Answer 8

Terpineol is a tertiary alcohol (and cannot be oxidised).

Question 9

Describe how free radicals are formed.

Answer 9

Bond breaking by UV (light).
OR
an example of an initiation reaction.

Question 10

State how free radical scavengers prevent further chain reactions.

Answer 10

Can react with free radicals forming stable molecules/ free radicals (and prevent chain reaction).
OR
Donates electron(s).
OR
Acting as a reducing agent.
OR
Provide electrons to pair with an unpaired electron.

Question 11

Explain fully why ethane-1,2-diol is more viscous than propan-1-ol.

Answer 11

Propan-1-ol has fewer hydroxyl groups than ethane-1,2-diol / ethane-1,2-diol has more hydroxyl groups/propan-1-ol has 1 hydroxyl group and ethane-1,2-diol has 2.

Stronger/more hydrogen bonds between ethane-1,2-diol molecules.
OR
Weaker/fewer hydrogen bonds between propan-1-ol molecules.

Question 12

Describe a procedure to accurately weigh put a 50.0g sample of ionised table salt.

Answer 12

Place weigh boat on balance then tear it. (Set to zero)

Then weigh out 50.0g of ionised salt.

Question 13

Describe the procedure which should be sued to prepare 100cm3 of the 20% ethanol solution.

Answer 13

• Use a pipette to measure out 20cm2 of ethanol.
• Add to volumetric flask.
• Fill volumetric flask to the graduation mark using distilled/ deionised water (must reach the bottom of the meniscus).
• Put a stopper in the flask and invert.

Question 14

State two conditions necessary for collisions to result in the formation of products.

Answer 14

Particles must have energy equal to or greater than the activation energy.
AND
Collisions must occur with the correct geometry.

Question 15

Explain why the first ionisation energy shows an increase going from lithium to neon.

Answer 15

Increasing nuclear charge

Question 16

Explain why the first ionisation energy of potassium is less than the first ionisation energy of lithium.

Answer 16

More electron shells so increased shielding.

Question 17

State what is meant by the term enzyme.

Answer 17

Biological catalyst.

Question 18

State the systemic name for glycerol.

Answer 18

Propane-1,2,3-triol.

Question 19

Name the molecule on which terpenes are based.

Answer 19

Isoprene(s).