What is a molecule?

A molecule is a particularly small group of non-metal atoms that are held together by covalent bond

Are ionic compounds soluble in water?

Chemistry is messy: most but not all ionic compounds are soluble in water

Gas collection: water displacement, upward delivery & downward delivery

The three methods of collecting gases by their physical properties

How to find the cation and anion in a compound?

What are ionic compounds and the ions they contain?

Differences between crystallisation and evaporation to dryness

Crystallisation and evaporation to dryness are two different methods to separate different solutes from their solution.

Transition elements: What makes Tanah Merah so merah?

Find out the transition element that dyes the soil in Tanah Merah brick red and gave the place its name.

Noble gases: The high and mighty helium

Helium was discovered on the sun before it was found on earth. What about it as a noble gas makes it so good at hiding?

Mixtures & pure substances: The mystery of air

For most part of human history, scientists could not correctly tell whether air is a single substance or a mixture.

Paper chromatography

Paper chromatography is a simple yet powerful detective tool to separate and analyse the substances in a mixture.

Simple distillation vs fractional distillation

A solution of two miscible liquids is tricky to separate. How can we solve it with fractional distillation, a modified version of simple…

What are isotopes?

Atoms of the same element may not be identical. The different forms of an element are called isotopes.

Distillation: An ancient technique to separate liquid

Distillation has been used to separate and purify liquid since more than 2000 years ago.

Proton: Getting particular about identifying elements

The proton is the subatomic particle that defines the chemical identity of an element.

Electron: What we know and can never know

The electron is the first subatomic particle to be discovered, turning chemistry on its head more than a century ago.

Carbon dioxide & other acidic oxides

Some oxides can behave like an acid and neutralise bases. How do you identify them?

What is atomic structure?

The atom is not a featureless ball. It consists subatomic particles arranged in a mind-boggling way.

Kinetic particle theory

The kinetic particle theory explains the visible with the invisible.

Global warning: Global warming

We can all play a part to clear the air of greenhouse gases to slow global warming.

What are cation and anion?

Have your eye on ion

Iron extraction and steelmaking

Ironing out how we get iron out of haematite