1-Chem-X Topic 1

What is the first rule before entering a laboratory?

Enter only when the teacher is present.

What should you do before starting an experiment?

Make sure you understand all the teacher's instructions.

May you perform an experiment by yourself?

No. Only perform experiments as instructed by the teacher.

Why must chemicals and apparatus not be removed from the laboratory?

They may be hazardous and must remain under controlled laboratory conditions.

Where should solids not be disposed of?

In the sink.

What activities are forbidden in a laboratory?

Eating, drinking, playing, and running.

When should safety goggles be worn?

When heating chemicals or working with chemicals, sharp objects, or fire.

When should gloves be worn?

When handling corrosive or dangerous chemicals.

Why must you never taste a chemical?

It may be toxic or otherwise harmful.

Why should unused chemicals not be returned to their original containers?

They may contaminate the chemicals in the containers.

Where should the mouth of a heated test tube point?

Away from yourself and everyone else.

Why must flammable substances be kept away from flames?

They can catch fire.

When should you wash your hands during laboratory work?

Before and after all laboratory work.

How can you avoid cross-contamination when using a dropper or spatula?

Wash and dry it before using it for another chemical.

What should you do after taking a chemical from a bottle?

Close the bottle.

What should you do after any accident, injury, breakage or spillage?

Report it to the teacher immediately.

What should you do if a chemical gets into your eyes or onto your body?

Rinse thoroughly with plenty of water and report it to the teacher.

What should you do after being burnt by hot water or apparatus?

Cool the area with plenty of cool water for a few minutes and report it to the teacher.

How should broken glass be cleared?

Use a broom and dustpan and place it in the glass-breakage box.

What does the general hazard or irritant symbol mean?

The chemical may irritate the skin, eyes, or respiratory tract.

How should you protect yourself from an irritant?

Avoid skin and eye contact; wear gloves and goggles.

What does the corrosive symbol mean?

The substance can destroy living tissue, including skin and eyes.

Give two examples of corrosive substances.

Acids and alkalis.

What precautions should be taken with corrosive substances?

Wear gloves and goggles, use a test-tube holder, work in a fume cupboard, and wash affected areas with plenty of water.

What does the explosive symbol mean?

The substance may explode when exposed to fire, heat, shock, or friction.

What precaution should be taken with explosive substances?

Keep them away from heat and flames.

What does the oxidising symbol mean?

The substance can support burning without air and make fires burn hotter and longer.

Give examples of oxidising substances.

Concentrated nitric acid and potassium manganate.

What does the flammable symbol mean?

The substance catches fire when exposed to sparks or heat.

Give examples of flammable substances.

Petrol, kerosene, hydrogen, and alcohol.

What does the toxic symbol mean?

The substance may cause serious harm or death.

How should you protect yourself from toxic substances?

Avoid inhaling gases, vapours or particles and wash your hands thoroughly after handling them.

What does the biohazard symbol mean?

Biological material may cause serious harm or death.

How should you protect yourself from biohazards?

Wear PPE, wash hands thoroughly and avoid touching your mouth, eyes, and nose.

What does the radioactive symbol warn of?

Radiation that may cause serious health problems and cancer.

What does the environmental hazard symbol mean?

The substance is toxic to aquatic organisms and may kill them.

What precaution applies to environmental hazards?

Do not release them into rivers, lakes, oceans or the wider environment.

What does the long-term health hazard symbol mean?

The substance may cause serious long-term health problems.

What does the compressed-gas symbol mean?

Gas is stored under pressure and its container may explode if heated.

What precaution applies to compressed gas?

Do not heat the container or bring it near heat or flames.

How should laboratory apparatus be drawn?

As cross-sectional diagrams, in correct proportions, using a sharp pencil and ruler.

What is a test tube used for?

Containing or heating small amounts of substances.

What is a boiling tube used for?

Containing or heating larger amounts of substances.

What is a beaker used for?

Containing chemicals or collecting liquids.

What is a conical flask used for?

Containing chemicals or collecting liquids.

What is a filter funnel used for?

Separating an insoluble solid from a liquid with filter paper.

What is an evaporating dish used for?

Evaporating a liquid from a solution.

What is a tripod stand used for?

Supporting apparatus during heating.

What is a retort stand used for?

Supporting apparatus during experiments.

What is a gas jar used for?

Collecting gases.

What is a measuring cylinder used for?

Measuring liquid volume to an accuracy of 1 cm³.

What is a round-bottomed flask used for?

Preparing gases when the process requires heating.

What is a Bunsen burner used for?

Heating solid substances or solutions.

What happens inside a Bunsen burner?

A flammable gas combines with oxygen and burns to produce a heating flame.

What is the function of a Bunsen burner's barrel?

It raises the flame to a suitable height for burning and heating.

What is the function of a Bunsen burner's collar?

It controls the air entering through the air hole.

What is the function of the gas tap?

It controls the amount of gas supplied to the burner.

What is the function of the air hole?

It allows air to enter the burner.

What is the function of the jet?

It allows gas to enter the burner.

What is the function of the base?

It supports and stabilises the burner.

Why is a luminous flame yellow?

Incomplete combustion occurs because there is insufficient oxygen.

Why is a non-luminous flame blue?

Complete combustion occurs because there is sufficient oxygen.

Compare the air holes for luminous and non-luminous flames.

The air hole is closed for a luminous flame and open for a non-luminous flame.

Compare the stability of luminous and non-luminous flames.

A luminous flame is unsteady; a non-luminous flame is steady.

Compare the temperatures of luminous and non-luminous flames.

A luminous flame is cooler; a non-luminous flame is much hotter.

Compare the soot produced by luminous and non-luminous flames.

A luminous flame produces much soot; a non-luminous flame produces little or none.

Which Bunsen flame is normally used for heating?

The blue, non-luminous flame.

What are the four steps for lighting a Bunsen burner?

Close the air hole; hold a lighted match or lighter near the barrel; slowly turn on the gas; slowly open the air hole halfway.

Why must the gas tap not be turned on before the ignition source is ready?

Gas can build up and cause an explosion.

What is strikeback?

The gas burns at the jet or air hole instead of at the mouth of the barrel.

What can cause strikeback?

Opening the air hole completely, allowing too much air into the burner.