Evaporating dish is made of:
- porcelain
- glass
- metal
- plastic
Answer
porcelain
Reason — Evaporating dish is a bowl-shaped container made of porcelain. It is used for evaporating solutions or liquids.
Spirit lamp is made of:
- glass
- brass
- steel
- all of the above
Answer
all of the above
Reason — Spirit lamp is a type of burner made of glass, brass or steel containing a wick. Spirit is used as fuel. It is used to heat up substances.
The apparatus used to measure an accurate volume of a liquid is:
- beaker
- conical flask
- measuring cylinder
- test tube
Answer
measuring cylinder
Reason — A measuring cylinder is a cylindrical glass apparatus graded in millilitres, decilitres and centilitres. It is used to measure the volume of liquid substances.
To pass a gas from one vessel to another, you will use a:
- gas jar
- delivery tube
- glass rod
- test tube
Answer
delivery tube
Reason — A delivery tube is made up of glass and is used to transfer fluids or gases from one vessel to another.
To prevent the escape of a gas from a gas jar, you will cover its mouth with a:
- watch glass
- crucible
- beaker
- round bottom flask
Answer
watch glass
Reason — A watch glass is made up of glass. It is used to cover beakers or glass jars, as it prevents gas from escaping and also used like evaporating dish for very small amount of liquid.
(a) Experiment and ............... are the two important basics of chemistry.
(b) A porcelain dish is used ...............
(c) ............... is used to hold the test tube while it is hot or being heated.
(d) ............... is used for grinding and crushing solid substances into a powder.
(e) Glass apparatus is made of ............... or ............... glass.
Answer
(a) Experiment and observation are the two important basics of chemistry.
(b) A porcelain dish is used for evaporating solutions.
(c) Test tube holder is used to hold the test tube while it is hot or being heated.
(d) Mortar and pestle is used for grinding and crushing solid substances into a powder.
(e) Glass apparatus is made of pyrex or borosil glass.
Write true or false against the following statements and correct the false ones.
(a) A glass funnel is used to pour off liquids. ...............
(b) A test tube is used to test liquid chemicals. ...............
(c) A mortar and pestle is used for evaporation. ...............
(d) A glass rod is used to stir solutions. ...............
(e) A round-bottom flask is used to store chemicals. ...............
Answer
(a) True
(b) True
(c) False
Correct Statement — A mortar and pestle is used for grinding and crushing solid substances.
(d) True
(e) False
Correct Statement — A round-bottom flask is used to hold solutions during experiments.
Match the items in column A with their respective functions in column B.
| Column A | Column B |
|---|---|
| (a) Iron stand | (i) To boil chemicals |
| (b) Test tube | (ii) To keep solutions |
| (c) Funnel | (iii) To stir solutions |
| (d) Beaker | (iv) To support apparatus |
| (e) Glass rod | (v) To transfer liquids |
Answer
| Column A | Column B |
|---|---|
| (a) Iron stand | (iv) To support apparatus |
| (b) Test tube | (i) To boil chemicals |
| (c) Funnel | (v) To transfer liquids |
| (d) Beaker | (ii) To keep solutions |
| (e) Glass rod | (iii) To stir solutions |
From what materials are the following made up of ?
(a) Test tube rack
(b) Test tube holder
(c) Measuring cylinder
(d) Wire gauze
(e) Mortar and pestle
Answer
(a) Wood or plastic
(b) Metal
(c) Glass
(d) Iron and asbestos sheet
(e) Porcelain
Mention one use of each of the following equipments:
(a) Spirit lamp
(b) Test tube
(c) Conical flask
(d) Evaporating dish
(e) Wire gauze
(f) Beaker
(g) Mortar and pestle
(h) Measuring cylinder
(i) Glass tube
(j) Gas jar
(k) Reagent bottle
Answer
(a) To heat up substances
(b) Test tube is used to conduct tests with small quantities of chemicals.
(c) To hold sufficient quantities of solutions during experiment.
(d) It is used for evaporating solutions or liquids.
(e) To keep glass apparatus on it while heating is in progress.
(f) For preparation and keeping of solutions.
(g) To grind and crush solid substances into powder.
(h) To measure the volume of liquid substance.
(i) It is used to transfer fluids or gases from one vessel to another.
(j) For collecting gas.
(k) To store chemicals.
Answer the following questions in brief:
(a) Why is chemistry known as an experimental science?
(b) Why are most of the apparatus made of glass?
Answer
(a) Chemistry is the branch of science which is mostly based on experiments and observations. An experiment performed under controlled conditions is an activity where we observe a natural or an artificially created phenomenon. Hence, chemistry is known as an experimental science.
(b) Most of the apparatus is made of glass due to the following reasons:
- Glass is a transparent material and we can see through it clearly.
- Glass can withstand high temperatures.
- Glass is easy to clean.
- Glass does not react with most of the chemicals used in experiments.
- Pyrex glass or borosil glass is a special type of glass which hardly expands on heating. Such glasses do not break even at high temperatures.
List any five precautions to be taken while performing an experiment in a chemistry laboratory.
Answer
- We should not work alone in the laboratory.
- We should always wear a lab coat in the laboratory. It protects our clothes.
- We must follow our teacher's instructions whenever we perform an experiment.
- We should not touch or taste any unknown substance or inhale any unknown gas directly.
- After the experiment is completed, we should properly wash, clean, dry the apparatus and put them back in their respective places in the laboratory.
Label the marked equipments and apparatus in the diagram given below.
Answer
- Glass tube or delivery tube
- Round bottom flask
- Wire gauze
- Tripod stand
- Bunsen burner
- Glass jar
- Beaker
- Chemical solution / Water