Carbon Chains

Chains of carbon ⛓️

Carbon atoms link into **chains**, and those chains build our **fuels** and **plastics**. Two great families of hydrocarbon run through them. This module meets the **alkanes** and the **alkenes**, learns to name and tell them apart, and uses one orange test to spot a **double bond**.

The language of hydrocarbons 🔑

Four ideas run through this module:

Two hydrocarbon families ⚖️

Both are hydrocarbons, but a single **double bond** sets them apart.

The double bond 🎯

Which family of hydrocarbons has a carbon-carbon double bond?

• Alkenes
• Alkanes
• Neither family
• Both families equally

Match each formula to its name 🔗

Which are alkenes? ✅

Select the TWO alkenes.

• Ethene
• Propene
• Methane
• Ethane

The bromine water test 🧪

Add orange **bromine water** to a hydrocarbon and shake. This one test tells the families apart. An **alkane** does not react, so the bromine water **stays orange**. An **alkene** makes the bromine add across its C=C, so the bromine water is **decolourised**.

Alkanes by chain length 🪜

An interactive activity.

It stays orange 🟠

You shake an unknown gas with orange bromine water and it stays orange. What is the gas?

• An alkane
• An alkene
• Ethene
• Water vapour

Hydrocarbons in words 🧩

A hydrocarbon contains only hydrogen and carbon. _____ are saturated, with only single bonds and the general formula _____. _____ are unsaturated, with a carbon-carbon double bond. When bromine water is added, an alkene _____ it, while an alkane leaves it _____.

Spot the true statements 🖍️

An interactive activity.

Match each term to what is true of it 🔀

Name that hydrocarbon 🧭

An interactive activity.

Alkane or alkene? ✍️

An interactive activity.