The laboratory of general chemistry

The laboratory is the place where experiments as well as scientific research may be carried out. It usually consists of one large room with a weighing room, a reagent room and sometimes a dark room. The reagent room is used for storing chemicals and apparatus, and contains shelves of reagent bottles. The weighing room is specially constructed so as not to be affected by external disturbances and the balances generally stand on firm stone shelves. The analytical balance, which is kept in a glass case, consists of a beam, which swings on a knife edge, and has two pans suspended, one from each end. The material which is to be weighed is transported to and from the balance room in a dessicator. Chemical laboratory operations deal with gases, liquids and solids, and require a variety of specialized apparatus for their manipulation.

The laboratory is furnished with many long tables or benches, as they are usually called. On each of these benches there are shelves and racks for keeping apparatus, materials, etc.

 

On the shelves there are many bottles with different chemical substances. Some bottles contain solids, others – liquids. The necessary assortment of the laboratory glassware includes evaporating dishes, separatory funnels, beakers, bulbs for boiling liquids? Dessicator for drying materials. In the racks we can see different glass tubes, test-tubes, condensers, flasks of different shapes and sizes, bowls, glass rods, crucibles, etc. Some crucibles are made of porcelain, others of quartz or platinum. They are used for igniting materials.

 

The apparatus used for carrying out experiments are clamped to ring-stands. The ring-stand consists of a stem having a ring with a copper gauze. Every working place is fitted with a Bunsen burner. The flame of the burner can be regulated by means of a tap. All the burners are connected with the main gas line by a rubber tube. Sometimes steam-baths, water-baths and air-baths are used for heating.

 

The laboratory is also provided with gas and running water. There is a ventilating hood for the escape of disagreeable odours and harmful vapours.

 

Exercise 1. Fill in the blanks.

1. The reagent room is used for … (storing / weighing) chemicals. 2. The weighing room is … (specially / generally) constructed … (so as / because) to be free from external disturbances. 3. Chemical laboratory operations … (deal with / require) liquids, solids and gases. 4. The apparatus used for … (transporting / carrying out) experiments are clamped to ring-stands. 5. The laboratory … (is operated / is provided) with gas and running water.

 

 

Exercise 2. Answer the questions

 

1. Where is scientific research carried out?

2. How many rooms does a laboratory usually consist of?

3. What is the reagent room used for? Where do balances usually stand?

4. What does the analytical balance consist of?

5. In what way is the material which is to be weighed transported?

6. What substances do chemical laboratory operations deal with?

7. What is the laboratory furnished with?

8. What is every working place fitted with?

9. What can the flame of the burners be regulated with?

10. Are all liquids colourless and odourless?

11. Where are liquids kept?

12. What is a crucible made of?

13. What are the apparatus used for carrying out experiments clamped to?

14. What is the laboratory provided with?

Exercise 3. Look through the Appendix 4 for the chemical part and name the equipment that you have in each of the laboratories.

 

Visiting a laboratory

 

Nick a third-year student, is showing the laboratory to his younger brother Alec, a schoolboy, who is going to enter the Institute.

N i c k: Here is our lab. Come in Alec.

A l e c: What a variety of smell you have here!

N i c k: No wonder, it is a chemical lab. (They come up to the bench where an analyst is working.)

A l e c: What is he doing?

N i c k: I believe he is heating a solution in a test-tube.

Why is he moving a test tube all the time?

N i c k: It is done to prevent superheating. He uses a microburner because direct heat is necessary in certain tests. Usually test-tubes are heated on the water bath.

A l e c: May I have a look at the water bath?

N i c k: Here is one. You see, its top has three holes to accommodate the test-tubes.

A l e c: What dish is there on the bench?

N i c k: That’s a crucible. We prefer to use crucibles since they don’t break.

A l e c: When do you use crucibles?

N i c k: We use crucibles when we carry out evaporations.

A l e c: Why don’t you use test-tubes far that purpose?

N i c k: Crucibles provide a greater surface from which evaporation may take place. Would you like to work in this lab?

A l e c: Oh, I am looking forward to the day when I’ll be a student and work in the lab. It is so interesting!

N i c k: So much the better.

 

Exercise 1.Match the word with its definition

 

1) funnel

2) beaker

3) microscope

4) slides

5) electric balance

6) tongs

7) mortar

8) pestle

9) tripod

10) rubber tubing

ll) gas tap

12) matches

13) measuring cylinder

14) test tube

15) test tube rack

16) pipette

17) conical flask

18) bung/stopper

19) 1ab coat

20) chemical

21) chemical reaction

22) chemist

23) chemistr

 

 

a) a tool that consists of two movable bars joined at one end, used to pick up an object

b) a scientific instrument that makes extremely small things look larger

c) a short stick with a heavy round end

d) the science that is concerned with studying the structure of substances and the way they change

e) a round piece of rubber or wood used to close the top of a container

f) a round pipe made of rubber for liquids to go through

g) a substance used in chemistry or produced by chemistry

h) a tube used for pouring liquids or powders into a container with a narrow opening

i) an electric instrument for weighing things

j) a natural process in which the atoms of chemicals mix and arrange themselves differently to form new substances

k) a glass container used for measuring liquid

l) a thing glass tube for sucking up exact amounts of liquid, used especially in chemistry

m) a small glass container that is shaped like a tube and is used in chemistry

n) a piece of clothing that is worn over your clothes in laboratory to protect them

o) a scientist who has a special knowledge in chemistry

p) a glass cup with straight sides that is used in chemistry for measuring and heating liquids

q) small pieces of thing glass used for holding something when you look at it under a microscope

r) a hard bowl in which substances are crushed into powder or very small pieces with a pestle

s) a special type of bottle mat you use to keep liquids

t) a special shelf for tubes

u) a support with three legs, used for a camera, telescope etc.

v) small wooden sticks, used, to light a tire

w) a piece of equipment for controlling the flow of gas from a pipe or containe

 

Exercise 2.

a)  You are in the chemical laboratory. There is a lot of special equipment. Your colleague asks you about one of the pieces of equipment. Make a short presentation of it (7 sentences). In your presentation speak about its shape, the material it is made of, and its usage. Give an example of when you use it.

b) One day your friend from philological faculty comes to see you in the laboratory of general chemistry. Everything is new to him and seems unusual. Give him a short excursion showing different equipment, describing experiments with chemical substances (15 sentences) and other reagents. Try to arouse his interest to your everyday activity.