Teacher Chemistry Lab Safety

1. Which one of the following is not a necessary item in your laboratory?

Fire Extinguisher

Fire blanket

Eyewash station

Spill kit

Gas and electricity cut-off switch

Fridge

A fridge is not a safety item in a laboratory. All of the other items are a must for every chemistry lab.

Explanation

A fridge is not a safety item in a laboratory. All of the other items are a must for every chemistry lab.

2. The hazard symbol shown represents

Irritant

Oxidising

Explosive

Flammable

Corrosive

The hazard symbol shown represents oxidising substances. These substances have the ability to release oxygen, which can cause or enhance the combustion of other materials. They are highly reactive and can pose a fire or explosion hazard if they come into contact with flammable or combustible materials. It is important to handle oxidising substances with caution to prevent accidents and ensure safety.

Explanation

The hazard symbol shown represents oxidising substances. These substances have the ability to release oxygen, which can cause or enhance the combustion of other materials. They are highly reactive and can pose a fire or explosion hazard if they come into contact with flammable or combustible materials. It is important to handle oxidising substances with caution to prevent accidents and ensure safety.

3. A first aid kit should be kept

Sealed in a locked cabinet

Safely in the preparation room

In the principal's office

Next to the teacher's desk

The correct answer is "next to the teacher's desk" because it is the most accessible location in case of an emergency. Placing the first aid kit next to the teacher's desk ensures that it can be easily and quickly accessed by both the teacher and students if needed. This location also allows for immediate response and treatment in case of minor injuries or accidents that may occur in the classroom.

Explanation

The correct answer is "next to the teacher's desk" because it is the most accessible location in case of an emergency. Placing the first aid kit next to the teacher's desk ensures that it can be easily and quickly accessed by both the teacher and students if needed. This location also allows for immediate response and treatment in case of minor injuries or accidents that may occur in the classroom.

4. A chemistry teacher wishes to make up a 1000 ml solution of a 0.1 M hydrochloric acid from a stock solution of 2 M HCl. What volume of the 2 M acid should be added to deionised water to make this solution up to 1000 ml? Give your answer as an integer with NO UNITS.

Correct. 50 mls.

The correct formula to use is M₁V₁ = M₂V₂

Explanation

Correct. 50 mls.

The correct formula to use is M₁V₁ = M₂V₂

Submit

5. Which is the correct fire extinguisher to use in each of the following cases? Each option has only one correct answer.

Paper catching fire

Flammable liquid

Sodium metal

Submit

6. A student's hair and clothes catches fire in the laboratory. Do you

Spray the student with foam fire extinguisher

Roll the student on the floor

Spray the student with carbon dioxide extinguisher

Tell the student to run to the principal's office

Walk the student calmly outdoors

Reprimand the student for not tying his/her hair back.

Rolling the student on the floor is the correct answer because it is the most effective way to extinguish the fire on their hair and clothes. By rolling, the flames are smothered, and the fire is deprived of oxygen, which helps to put it out. Spraying the student with foam or carbon dioxide extinguishers may not be as effective in this situation, as they are designed for larger fires and may not be readily available in a laboratory. Telling the student to run to the principal's office or walking calmly outdoors may waste time and allow the fire to spread. Reprimanding the student is not a priority in this emergency situation.

Explanation

Rolling the student on the floor is the correct answer because it is the most effective way to extinguish the fire on their hair and clothes. By rolling, the flames are smothered, and the fire is deprived of oxygen, which helps to put it out. Spraying the student with foam or carbon dioxide extinguishers may not be as effective in this situation, as they are designed for larger fires and may not be readily available in a laboratory. Telling the student to run to the principal's office or walking calmly outdoors may waste time and allow the fire to spread. Reprimanding the student is not a priority in this emergency situation.

7. Gafety goggles should be disinfected

After each laboratory practical

Weekly

Monthly

At the end of each school year

Safety goggles should be disinfected after each laboratory practical to ensure that any potential contaminants or hazardous substances are removed. This practice helps to maintain a clean and safe environment for future use, preventing the spread of bacteria or chemicals that could potentially harm the user's eyes. Regular disinfection after each use is crucial in maintaining the effectiveness of the goggles and ensuring the safety of the wearer.

Explanation

Safety goggles should be disinfected after each laboratory practical to ensure that any potential contaminants or hazardous substances are removed. This practice helps to maintain a clean and safe environment for future use, preventing the spread of bacteria or chemicals that could potentially harm the user's eyes. Regular disinfection after each use is crucial in maintaining the effectiveness of the goggles and ensuring the safety of the wearer.

8. Chemicals are often stored using a colour code. Match the codes below with their hazards.

Yellow

White

Red

Blue

Green

Grey

Submit

9. A 98% solution of sulfuric acid has a concentration of

19.8 M

12.8 M

9.8 M

6.8 M

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Explanation

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10. You have finished preparing a solution of sodium hydrogencarbonate and have about 5 grams of unused solid left in a beaker. Do you

Put the unused solid back ito its jar, as there is a limited school budget for chemicals.

React it with hydrochloric acid to neutralise it.

Wash it down the sink with a copious amount of water.

Putting it back in the jar may contaminate the rest of the sodium hydrogencarbonate.
Reacting it with acid until neutralised is time consuming and wasteful of more chemicals to say the least.
Washing it down the sink would be the preferred choice.

Explanation

Putting it back in the jar may contaminate the rest of the sodium hydrogencarbonate.
Reacting it with acid until neutralised is time consuming and wasteful of more chemicals to say the least.
Washing it down the sink would be the preferred choice.

11. From the following list, select the chemicals which should NEVER be stored with each other.

Ethanoic acid

Nitric acid

Ammonia

*##*•Small amounts of ethanoic acid will cause acetaldehyde to polymerise, releasing large amounts of heat.

•Nitric acid and ethanoic acid, when mixed can cause dangerous flash fires. This is due to nitric acid being a very strong oxidizing agent and acetic acid being an organic.

•Unstable nitrogen tribromide is formed, explosion may result.*##*

Explanation

*##*•Small amounts of ethanoic acid will cause acetaldehyde to polymerise, releasing large amounts of heat.

•Nitric acid and ethanoic acid, when mixed can cause dangerous flash fires. This is due to nitric acid being a very strong oxidizing agent and acetic acid being an organic.

•Unstable nitrogen tribromide is formed, explosion may result.*##*

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