Organic Question Christmas

Question 1

What colour is phenlymethanol at room temp?

Answer 1

Colourless

Question 2

Name a suitable apparatus to measure 1.5cm3 of phenylmethanol

Answer 2

Graduated syringe

Question 3

How does Appearance of the oxidation of phenylmethanol change with KMnO4

Answer 3

Purple to brown mixture

Question 4

Name a suitable technique to purify benzoic acid crystals

Answer 4

Recrystallisation

Question 5

How would you measure the melting point of a sample of benzoic acid crystals?

Answer 5

Put Sample on aluminium block shown in diagram, heat slowly while observing crystals, record temperature range at which melting occurs

Question 6

What was observed when a short strip of freshly sanded magnesium was added to a test tube containing Ethanoic acid

Answer 6

Bubbling, solid disappears

Question 7

Write formulae for products of Ethanoic acid

Answer 7

H2, C4H6O4Mg

Question 8

Identify catalyst in ethene reaction

Answer 8

Alumina - white powder

Question 9

Why is there a risk of hot glassware shattering due to rapid cooling and how can this be minimised?

Answer 9

Cold water enters hot test tube

Loosen stopper before reducing heat

Question 10

Why in recrystallisation is there no need to carry out a filtration of the hot solution

Answer 10

No insoluble impurities, sodium chloride soluble

Question 11

State one advantage of suction filtration over gravity filtration

Answer 11

Faster

Question 12

Explain how you could verify that the recrystallised benzoic acid was purer than the original sample

Answer 12

Measure melting points of both samples, purer melting point higher

Question 13

What was observed when water was dropped onto calcium carbide

Answer 13

Reaction turns milky, bubbling

Question 14

State and explain 2 safety precautions when preparing ethene and ethyne

Answer 14

Keep long hair tied back - avoids burns

Wear mask - avoid contact with chemicals

Question 15

Why were the first few test tubes of preparation of ethyne discarded

Answer 15

Contain air

Question 16

Compare observations in ethyne and ethene tests

Answer 16

Ethyne flame smokier than ethenes, ethene flame cleaner than ethynes

Question 17

Write a balanced equation for the complete combustion of ethyne in oxygen

Answer 17

C2H2 + 02 ->CO2 + H2O

Needs to be balanced

Question 18

Name a reagent used to test gases for unsaturation

Answer 18

Bromine solution

Question 19

How would you test ethyne and ethene for unsaturation

Answer 19

Bromine solution decolourises if unsaturated

Question 20

Describe a test to confirm that ethanal can be very easily oxidised

Answer 20

1) Add fehlings
2) heat gently
3) giving brick red precipitate

Question 21

If water was added to liquid x and y and shaken and white was observed in x and y was colourless. Identify x and y

Answer 21

X = Eugenol
Y = Ethanoic acid

Question 22

A small volume of cyclohexane was added to eugenol and shaken. What was observed when it was left to stand

Answer 22

Two layers

Question 23

Write a balanced equation for magnesium and Ethanoic acid

Answer 23

2CH3COOH + Mg -> (CH3COO)2Mg + H2

Question 24

Name a laboratory technique to purify impure benzoic acid

Answer 24

Recrystallisation