← Combined Science syllabus

SingaporeCombined Science

Chemistry: Metals and Organic Chemistry

4 dot points across 4 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How are ethanol and ethanoic acid made and used, and how are they linked by oxidation and esterification?

Describe the alcohols and carboxylic acids as homologous series, including the production and reactions of ethanol and ethanoic acid and the formation of esters
A focused answer to the O-Level Combined Science outcome on alcohols and carboxylic acids. Ethanol by fermentation and hydration, oxidation of ethanol to ethanoic acid, the reactions of carboxylic acids, and ester formation.
10 min answer →

What is a homologous series, and how do the bonding and reactions of alkanes and alkenes differ?

Describe alkanes and alkenes as homologous series, compare their bonding and reactions, and use the bromine test to distinguish saturated from unsaturated hydrocarbons
A focused answer to the O-Level Combined Science outcome on hydrocarbons. Homologous series and general formulae, saturated alkanes and unsaturated alkenes, combustion and addition, and the bromine test for a double bond.
10 min answer →

Why is iron extracted by heating with carbon but aluminium by electrolysis, and how does reactivity decide the method?

Relate the method of extracting a metal to its position in the reactivity series, describing reduction of iron in the blast furnace and extraction of aluminium by electrolysis
A focused answer to the O-Level Combined Science outcome on extracting metals. Linking extraction method to reactivity, reduction of iron oxide with carbon in the blast furnace, and the electrolysis of aluminium oxide.
10 min answer →

How do we order metals by how reactive they are, and how does that order predict displacement reactions?

Place metals in order of reactivity from their reactions with water, acids and oxygen, and use the reactivity series to predict displacement reactions
A focused answer to the O-Level Combined Science outcome on the reactivity series. Ordering metals from reactions with water, acid and oxygen, and using the series to predict displacement reactions and competition for oxygen.
9 min answer →