AS 2 observations

Question 1

What is the observation for burning a hydrocarbon?

Answer 1

A smoky flame = high carbon content

Question 2

Test for alkenes

Answer 2

Add a few cm3 of bromine water, after shaking the aqueous layer will decolourise

Question 3

Burning of alcohols

Answer 3

Clean blue - complete combustion

Smoky - incomplete combustion

Question 4

Reactions of alcohols with Sodium, Phosphorus pentachloride

Answer 4

Sodium - Solid disappears, fizzing, mixture warms up

PCl5 - Solid disappears, misty fumes, mixture warms up

Question 5

Reactions of Group 2 elements with water, HCl, H2SO4, and oxygen.

Answer 5

Water:
Mg - few bubbles produced slowly, metal dulls
Ca - Fizzing, mixture warms up, white solid produced

HCl
-Metal disappears, fizzing, mixture warms up

H2SO4

• Mg - Metal disappears, fizzing, mixture warms up
• Ca - Fizzing initially but reaction stops

Oxygen

• Mg - bright white light to form a white powder
• Ca - Brick red flame to form a white powder