Thursday, December 15, 2011

learn Symbols

Question 1 (15 points)
Match the symbols with the name

iron
silicon
lead
copper
zinc
sulfur
potassium
sodium
silver
gold
phosphorus
barium
bromine
iodine
chlorine

Sunday, September 4, 2011

Class X - Chemistry Theory. Sample Question Paper 1

Class X Theory- chemistry.. Question Paper - 1

By Sulekha Rani.R, PGT Chemistry, KV NTPC Kayamkulam

A Metal is treated with dil H₂SO₄ acid. The gas evolved is collected by the method shown in the figure. Answer the following

(1) Name the gas

(2) Name the method of collection

(3) Is the gas soluble or insoluble in water

(4) Is the gas lighter or heavier than air 2m

2. 2. Dry HCl gas does not turn blue litmus red where as hydrochloric acid does.Give one reason? 1m

3. Identify substance oxidised and reduced in the following reaction

MnO₂ + 4 HCl MnCl₂ + Cl₂ + 2H₂O 1m

4. A student dropped few pieces of marble in dilute hydrochloric acid contained in a test tube. The evolved gas was passed through lime water. What change would be observed in lime water? Write balanced chemical equation for both the changes occurred 3m

2. 5. Answer the following

(1) why is plaster of paris written as CaSO₄. ½ H₂O ? How is it possible to have half a water molecule attached to CaSO₄

(2) Why is NaHCO₃ an essential ingredient in antacids?

(3) When electricity is passed through an aqueous solution of sodium chloride three products are obtained. Why is the process called chlor alkali method ? 3m

6. Give reason

(a) During summer season milkman adds a very small amount of baking soda to fresh milk

(b) Potato chips manufacturers fill the packet of chips with nitrogen gas

(c) Tap water conduct electricity whereas distilled water does not.

(d) Water be never added to conc H₂SO₄

(e) Why copper vessels should not be used for keeping curd 5m.

7 . What will happen if a spoon of iron is used to stirring copper sulphate solution. 1m

8. What is amphoteric oxide ? give one example? Also write chemical equation. 2m

9. Why Plaster of Paris should be stored in moisture proof container? 1m

10. Write any 2 uses of the following

(1) NaHCO₃ (2) CaOCl₂ (3) NaOH (4) Plaster of paris

Wednesday, August 31, 2011

CHEMISTRY SAFETY SYMBOLS

Chemistry ... Safety Symbols...

By Sulekha Rani.R , PGT Chemistry, KV NTPC Kayamkulam

Corrosive

Will destroy or irreversibly damage another substance with which it comes in contact. The main hazards include damage to eyes, skin and tissue under the skin, but inhalation or ingestion are also very risky. Avoid contact, and bear in mind that these can (under some ciurcumstances) rust chemical cupboards.

Flammable Symbol

Flammable or extremely flammable
Chemicals to be stored in flame-resistant cupboards. Volatile solvents can be a particular problem as they are prone to spread around from unsealed containers. This also covers pyrophoric materials (that catch fire spontaneously on exposure to air).

POISONOUS

Poisonous

The poison symbol is self-explanatory. Whereas most chemicals are fairly dangerous if ingested or inhaled, many of these are dangerous even on contact.

Oxidising chemical

Oxidising chemical

Oxidising chemicals are materials that spontaneously evolve oxygen at room temperature or with slight heating, or that promote combustion. To be kept away from flammable chemicals at all costs!

Explosive

Explosive
Again, fairly self-explanatory, though fairly seldom seen in the average lab. Bear in mind that noise and movement can also trigger explosion (not just sparks/flames!).

Environmental hazard

Environmental hazard
Relatively rare with laboratory chemicals (most of which pose some environmental hazard if not got rid of correctly), these require particular care to be taken on disposal.

radiation warning

BIO HAZARD

ionizing radiation warning symbol

Radio waves hazard symbol

Non-Ionising radiation

CHEMICAL WEAPON

MCQ Chemistry X- SA1 (3)

MCQ - chemistry - SA1

By Sulekha Rani.R, PGT Chemistry, KV NTPC Kayamkulam

1. On putting a few drop of a liquid on pH stripe , the colour of pH stripe changed to green. the liquid is most probably

(a) lemon juice (b) dil HCl (c) NaOH solution (d)water

2. When a few drops of universal indicator were added to a dil solution of HCl,it is observed that the colour of the solution becomes

(a) colourless to blue (b) Colourless to red (c) blue to colourless (d) colourless to green

3. Zn granules added to dil HCl , colour of Zn granules changes to

(a) yellow (b) brown (c) black (d) white

4. Aluminium powder was added to Copper sulphate solution, colour of the solution changes from

(a) colourless to blue

(b) blue to colourless

(d) reddish brown to lightgreen

5. Barium chloride solution added to sodium sulphate solution, the following happenes.

(a) a white precipitate is formed

(b)a red precipitate is formed

(d) the pungent smelling gas evolved

MCQ Chemistry - X SA1 - (2)

MCQ SA1 Chemistry- sample paper 2

By Sulekha Rani.R , PGT Chemistry, KV NTPC Kayamkulam

1.
A student observed that the colour of pH paper changed to green when she dipped it in

water. She added a few drops of concentrated hydrochloric acid to the water. The colour

of pH would turn to

(a) light red.

(b) apple green.

(d) lemon yellow.

2. The colour of NO2

and PbO formed when lead nitrate is heated are :

(a) brown and green

(b) brown and yellow

(d) colourless and yellow

3. Bottle A contains oxalic acid and bottle B contains sodium carbonate solution. When pH

paper is dipped in each of the solutions, the colour seen in A and B respectively be

(a) orange, blue.

(b) blue, orange.

(d) orange, green

4. Which of the following is a correct observation when water is added to lime?

(a) No change and a hissing sound

(b) Vigorous bubbling and a hissing sound

(d) Vigorous bubbling with evolution of heat and a hissing sound

5. Copper sulphate solution is added to a test tube containing a clean iron nail. The correct

description regarding the deposition of copper on the iron nail would be that it starts

depositing

(a) at the tip of the nail

(b) from the head of the nail

(d) anywhere on the nail

6. . Two beakers A and B contain Iron (II) sulphate solution. In the beaker A is placed a small

piece of copper and in the beaker B is placed a small piece of zinc. It is found that a grey

deposit forms on the zinc but not on the copper. From these observations it can be

concluded.

(a) Zinc is most active metal followed by iron and copper.

(b) Zinc is most active metal followed by copper and then iron.

(d) Iron is most active metal followed by copper and then zinc.

7. On heating ferrous sulphate crystals, one would get

(a) Sweet smell

(b) Rotten egg smell

(d) none of the above

Sunday, August 21, 2011

MCQ Chemistry X- SA1 (1)

MCQ For X SA1 Chemistry - paper 1

14 questions ..each carry 1 mark.

By Sulekha Rani.R , PGT Chemistry, KV NTPC Kayamkulam

1. The two colours seen at the extreme ends of the pH chart are

(a) red and blue.

(b) red and green.

(d) orange and green

2. A student observed that the colour of pH paper changes to green when she

dipped it in water. She added a few drops of concentrated hydrochloric acid to

the water. The colour of pH paper would turn to

(a) light red.

(b) apple green.

(d) lemon yellow.

3. When zinc reacts with dilute hydrochloric acid

(a) the surface of zinc becomes brighter.

(b) the surface of zinc becomes black and dull.

(d) the reaction mixture turns green.

4. 10 mL of freshly prepared iron sulphate was taken in each of four test tubes.

Strips of copper, iron, zinc and aluminium were introduced, each metal in a

different test tube. A black residue was obtained in two of them. The right pair of

metals forming the precipitates is

(a) copper and zinc.

(b) aluminium and copper.

(d) zinc and aluminium.

5. A strip of copper was placed in a beaker containing zinc sulphate solution. On

observing the strip the next day, it was noticed that

(a) the copper strip remained as it was.

(b) the copper strip became thinner.

(d) the colour of the strip changed.

6. A student tested the pH of distilled water and found that the colour of the pH

paper changed to green. He checked the pH again after dissolving a pinch of

common salt in it. The colour of the pH paper this time was

(a) green.

(b) yellow.

(d) blue

7. Bottle A contains oxalic acid and bottle B contains sodium carbonate solution.

When pH paper is dipped in each of the solutions, the colour seen in A and B

respectively be

(a) orange, blue.

(b) blue, orange.

(d) orange, green.

8. The zinc metal used in the laboratory for doing experiments is available in the

form of

(a) filings.

(b) strips.

(d) pellets.

9. . When you place an iron nail in copper sulphate solution, the reddish brown

coating formed on the nail is

(a) soft and dull.

(b) hard and flaky.

(d) rough and granular.

10. When you place an iron strip in the solution of copper sulphate, the time required

for the colour of the solution to change from blue to green is about

(a) a second.

(b) an hour.

(d) 24 hours

11. On adding sodium bicarbonate to acetic acid, you immediately

(a) observe strong effervescence.

(b) hear hissing sound.

(d) notice formation of bubbles.

12. A student took the following samples to find out their pH using pH paper. The

teacher remarked that one of the samples taken was not proper. The teacher was

referring to

(a) dilute hydrochloric acid.

(b) lemon juice.

(d) soap solution.

13. To test the presence of an acid with a strip of red litmus paper you would

(a) dip the strip as it is in the sample and see the colour change.

(b) moisten the paper with water and dip in the given sample.

(d) first dip strip in alkaline solution and then use it to test the sample.

14. A student was given three samples containing ethanoic acid, sodium bicarbonate

solution and water in test tubes I, II and III, respectively. On dipping a pH paper

in them, he observed that the colour turned orange in I, blue in II and green in III.

If arranged in increasing order of their pH, the sequence of these bottles would be

(a) I, III, II.

(b) I, II, III.

(d) II, III, I.

Monday, May 9, 2011

Chapter 1 Questions for practice-

Questions for practice.

Sulekha Rani.R, P.G.T Chemistry , K V NTPC Kayamkulam

Chapter 1-Chemical reactions

1. Define the following

(a) combination reaction

(b) Decomposition reaction

(c) displacement reaction

(d) Double displacement reaction

2. Explain why reaction between quick lime and water is a combination

reaction? name the produact and writes its balancechemical equation?

3. what will happens and identify the chemical reaction and write balanced

chemical equation

(a) lead nitrate on heating

(b) burning of magnesium

(c) add water to quick lime

(d) silver chloride exposed to sunlight

(e) pass electricity throgh acidified water

(f) during respiration

(g) limestone is heated

(h) burning of coal

(i) on heating copper powder in air in a china dish.

(i) sulphuric acid is added to barium chloride solution?

4. Give one example of a chemical change in which heat is liberated?

5. Give one example of a chemical change in which heat is absorbed?

6. Why is respiration considered as exothermic?

7. Pb(NO₃)_{2 reacted with KI (i) type of reaction (ii) name the precipitate and mention its colour (iii) write balance chemical equation.}

Holyday Chemistry Project for Class X

Sulekha Rani.R, P.G.T Chemistry , K V NTPC Kayamkulam

1. Prepare your own indicator ( refer NCERT text book)

(for the preparation you can select... red cabbage leaves, turmeric(haldi) petals of some coloured flowers)
2. Using your indicator test the following substance and find out whether they are acid or base.
these materials you can collect from your surroundings and from your home.
vinegar, bakking soda (appakkaram) , soap solution, tamarind juice, lemon juice ,
tomatto juice, milk.
Format for writting project.
1. Aim and Objective
2. Materials required
3. Theory
4. Procedure
5. Observation ( table includes. substance tested, indicator colour, colour change, inferance)
6. Result and conclution .