Name: b1u03 labequipment2 srt
Uploaded: 2025-09-10T14:02:59.000Z
Duration: 4 min 41 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

The main heat source in most chemistry labs is the Bunsen burner.

It produces an open gas flame burning at a high temperature.

Adverbs of manner

There's always the danger of an accident if it's not used properly.

For example, it should never be used to heat volatile organic liquids that give off flammable vapors.

These substances should be heated in a heating mantle or a steam bath in a hood.

But for most other substances, a Bunsen burner is an ideal heat source when used properly.

There are several types of Bunsen burners, but they all have the same basic parts.

The gas comes from an outlet on the lab bench.

A rubber hose fits over the tip and over a similar fitting on the Bunsen burner.

Most burners have a valve at the bottom to control the flow of gas.

Air inlets control the amount of oxygen in the flame.

A wingtop can be placed on the burner to spread the flame out.

There are several important rules to follow to use a Bunsen burner safely.

Make sure the hose fits securely on the gas valve and on the Bunsen burner.

The gas valve at the bottom of the burner should be open.

You can light a Bunsen burner with a striker or a match.

Open the gas line valve and light the burner.

If the flame is properly adjusted, you can place the burner under your setup.

Opening the air holes lets in more oxygen for combustion.

Adjust the bottom valve if the flame is too large or small.

The flame should be blue with a lighter inner cone.

The tip of the inner cone is the hottest part of the flame.

If the flame begins to sputter or flare, turn the gas off immediately.

Also turn the gas off immediately if the flame goes out.

Flat-bottomed containers are normally heated on a wire screen on a ring stand.

Erlenmeyer flasks and other narrow-necked containers should be secured to the stand with a clamp.

Test tubes can be heated in a water bath.

The water bath transfers heat slowly and evenly to the test tube and helps keep it from boiling over.

You can also heat a test tube directly in the flame.

Hold it at an angle while moving it back and forth to distribute the heat evenly.

Aim it away from yourself and your neighbors.  In case it boils over.

A boiling liquid changes to gas, which must be able to escape.

Gas can't escape from a closed container and the pressure that builds up can burst it.

Be extra careful when working with heated equipment.

Hold hot glassware in beaker tongs, never your hands.

Remember that the wire screen and ring stand are also hot.

If you don't have tongs, protect your hands with gloves designed for hot glassware.

Handle everything as if it's hot if you've been using a Bunsen burner.

Glass and metal look the same when hot as they do when they're cold.