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Preparing the Heating Apparatus

Imagine trying to boil water in a glass beaker over a campfire—it would shatter instantly. In the lab, we use a specific setup to control heat safely and prevent damage to our equipment.

All heating must take place on a heat-proof mat placed 30–40 cm from the edge of the bench to protect the surface from scorching.
The Bunsen burner is positioned under a tripod, which is a three-legged metal stand that holds the apparatus at the correct height.
A wire gauze is placed flat on top of the tripod. This mesh spreads the heat from the flame evenly across the bottom of the glassware, preventing "hot spots" that cause glassware to crack or liquid to boil unevenly (a hazard known as bumping).
Standard safety equipment must be worn: safety goggles, a lab coat, and long hair must be tied back.

Step-by-Step: Lighting a Bunsen Burner

Lighting a Bunsen burner requires a strict sequence to prevent dangerous gas build-ups.

First, inspect the rubber tubing for cracks and connect it securely to the gas tap.
Next, turn the collar at the base of the chimney to ensure the air hole is fully closed.
Then, light a wooden splint or match before turning on the gas.
Finally, hold the lit splint just above the chimney and turn the gas tap to the "on" position to ignite the gas.

Controlling the Flame

The amount of oxygen mixing with the gas determines the temperature and colour of the flame.

Safety flame: Produced when the air hole is fully closed. It is a highly visible, bright yellow, and unsteady luminous flame at approximately 300°C. It results from the incomplete combustion of methane, which produces soot (carbon) and carbon monoxide:

Students often state they would 'turn on the gas, then light the splint' — this is dangerous as gas can build up. You must explicitly state that the splint is lit before the gas tap is turned on.

In exam methods, always specify that the air hole must be closed when initially lighting the burner to produce a visible safety flame.

For flame test questions (PAG 5), examiners will deduct marks if you use a yellow flame; you must specify a 'roaring blue flame' so the soot and yellow colour do not mask the metal ion results.

When asked about the purpose of the wire gauze, examiners are looking for the exact phrase 'distributes heat evenly' rather than simply 'supports the beaker'.

A heat-resistant surface placed under heating apparatus to protect the laboratory bench from heat damage and scorching.

A laboratory device connected to a gas tap that burns a mixture of gas and air to provide a controllable flame for heating.

A three-legged metal stand used to support laboratory apparatus above a Bunsen burner.

A square sheet of metal mesh used to support glassware and ensure uniform heat distribution.

The sudden, violent formation of a large vapour bubble that can splash hot liquid out of a container during uneven heating.

The adjustable metal ring at the base of the chimney used to control the amount of air entering the burner.

The vertical metal tube of a Bunsen burner where the gas and air mix before combustion.

An opening at the base of a Bunsen burner that can be adjusted using the collar to control the oxygen supply.

A yellow, luminous, and flickering flame produced when the air hole is fully closed, representing the coolest flame.

A bright yellow flame that gives off light, produced when the air hole is closed and characterized by glowing soot particles.

A reaction where the fuel reacts with a limited supply of oxygen, producing carbon (soot) and carbon monoxide alongside water.

A silent blue flame produced when the air hole is partially open, used for the gentle heating of liquids.

The hottest flame produced when the air hole is fully open, characterized by a pale blue colour, an inner blue cone, and a roaring sound.

A blue, nearly invisible flame produced when the air hole is open, allowing for complete combustion without producing soot.

A reaction where the fuel reacts with excess oxygen to produce only carbon dioxide and water.