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Wednesday, 30 August 2017

CLASS -8

(Microorganism: Friend and Foe)

Multiple Choice Question- (1 Marks Each)

1.Bacteria are classified according to their:

	i) Shape	ii) size		iii) color		iv) none of these
2.	The first antibiotic discovered was:
	i) Penicillin	ii) Tetracycline		iii) Streptomycin		iv) Bacitracin
3.	Cholera is caused by:
	i) vibrio cholera	ii) clostridium tetani iii) salmonella typhi					iv) none of these
4.	A common bacterial disease in plants is:
	i) Citrus canker	ii) Rabies		iii) Polio		iv) All of these
5.A common food preservative is:
	i) Benzoic acid	ii) Hydrochloric acid iii) Sulphuric acid						iv) Nitric acid
6.	An edible fungi is:
	i) Mould	ii) Mushroom		iii) Algae		iv) None of these
7.	The smallest microorganism is:
	i) Algae	ii) Protozoan		iii) Bacterium		iv) Virus
8.	Algae are:
	i) Autotrophs ii) Parasites iii) Heterotrophy				iv) Saprophytes
9.	The microorganisms that play an important role in maintaining the balance of							nitrogen gas in the
	atmosphere are:
	i) Bacteria	ii) Algae	iii) Virus		iv) Protozoa

10. Which of these are added to dough to make it rise?

i) Yeast

ii) Algae

iii) garbage

iv) all of these

Fill in the blanks:- (1 Marks Each)

1.Microorganisms can be seen with the help of a ……………………..

2.Blue green algae fix ……………….. Directly from air to enhance fertility of soil.

3.Alcohol is produced with the help of ……………………….

4.Cholera is caused by …………………….

5.………………….. are non-green plants.

6.………………….. cause fermentation.

7.……………………….. and ………………………. Are diseases caused by fungi in humans.

8.A ………………….. found in the intestine of termite, help them to digest word cellulose.

9.…………………… only multiply in the body of a living organism.

10.……………….. is a fatal disease of humans as well as cattle.

Very Short Answer Question: (1 Marks Each)

1.Write the names of some diseases caused by virus.

2.What is the main ingredient of rava idlis and bhaturas.

3.What is fermentation?

4.Mention tow groups of Microorganisms on the basis of their functions?

5.Name some diseases caused by protozaans.

Short answer questions:

(2 Marks Each)

1.What are microorganisms?

2.How do microbes survive in adverse conditions?

3.How bacteria are useful to us?

4.What is virus?

5.What is fermentation? Where is it used?

6.Write two common bacterial disease of human and write preventive measures for it?

7.What is the role of yeast in baking industry ?

8.Write sum commercial use of microorganisms?

9.What is pasteurization of milk?

10.How do microorganisms spoil food?

Answer these question		(3 Marks Each)
1.	What are major groups of microorganisms?
2.	Draw any protozoa and Label its part.
3.	What are the antibiotics? What precautions one should take while taking them?
4.	How do bacteria help in increasing soil fertility? Explain.
5.	Classify the bacteria according to their shape.
6.	What are communicable diseases ? Explain with examples.
7.	What do you mean by food poisoning ?
8.	Explain how does a vaccine work?
9.	Describe the role of blue green alae and bacteria in fertility of soil ?
10.	Give one example of each.

i) an edible fungi	ii) antibiotic obtained from fungi
iii) a parasitic protozoan	iv) nitrogen fixing bacteria
v) a bacteria residing in intestines of man	vi) what is nitrogen cycle
Long answer questions.	(5 Marks Each)

1.Draw and explain the harmfull effects of bactria with Example.

2.What are food preservatives ? Explain some common food preservatives.

3.Explain cousative microorganisms, mode of transmission and preventive measure of the humand diseases like Tuberculosis, Measles, Chicken pox, Polio, Cholera, Typhoid, Hepatitis B and Maleria etc.

4.Explain Nitrogen Cycle with the help of Label Diagram?

5.Draw different types of fungi and write useful and harmful effect of fungi.

CLASS -10
CHEMISTRY WORKSHEET.

CHEMISTRY 30M

1. Name two organic acids. 1M

2. Which of the following reactions is not correct?

Zn +CuSO₄ → ZnSO₄+ Cu

Ag +Cu (NO₃)₂ → Ag(NO₃)₂ +Cu

Fe+ CuSO₄ → FeSO₄+ Cu

2Mg + 2HCl→ MgCl₂+ H₂

3. Washing soda has the formula

Na2 CO3.7 H 2O

Na2 CO3.10 H2 O

Na2 CO3.2 H 2O

Na2 CO3

4. Which of the following is evolved when Na2CO3 is heated?

a. (a) CO2 (b) CO (c) O2 (d) No 1M

5. Why does not an acid show any acidic behavior in the absence of water?

6. Fresh milk has a pH of 6. What will be the PH value if milk changes into a curd Justify. 2M

7. A housewife found that the cake prepared by her is hard and small in size. Which ingredient has she forgotten to add that would have made the cake fluffy. Give reason.

8. What is water of crystallization. Name two hydrated salts. 2M

9. 2. “Write the balanced chemical equations for the following and identify the type of reaction in each case: 3M

Barium chloride (aq) + potassium sulphate (aq) ---- Barium sulphate (s) + Potassium chloride (aq)

Zinc carbonate (s) ------- Zinc oxide (s) + Carbon dioxide (g)

Magnesium (s) + Hydrochloric acid (aq) ------- Magnesium chloride (aq) + Hydrogen(g)

10. . 1 Write short notes with examples on following:

a. Corrosion

b. rancidity 3M

11. 18.In the reaction MnO₂ +4HCl--------- MnCl₂ + 2H₂O +Cl₂

a. Name the substance oxidised.

b. Name the oxidising agent.

c. Name the reducing agent and the substance reduced.

12. Give one example each of

Thermal decomposition

Electrolytic decomposition

Photo decomposition 3M

13. How is plaster of Paris chemically different from gypsum? How may these be inter converted? Write one use of plaster of Paris? 3M

14. Why does a solution of sodium chloride conduct electricity while solid sodium chloride does not? 3M

With the help of chemical equations show that Al203 is an amphoteric oxide?

Shoe the formation of

NaCl , Na₂O, MgCl₂,AlCl₃

CLASS-9
CHEMISTRY WORKSHEET

1. The rate of evaporation decreases with 1M

a. (a) increase in humidity (b) increase of temperature

b. (c) increase in wind speed (d) increase of surface area

2. Arrange the following substances in increasing order of force of attraction between the particles.

a. (i) milk (ii) salt (iii) oxygen 1M

3. Choose the correct statement of the following:

(a) Conversion of solid into vapours without passing through the liquid state is called vaporization.

(b) Conversion of vapours into solid without passing through the liquid state is called sublimation.

(d) Conversion of solid into liquid is called sublimation. 1M

4. What is the value of boiling point of water on Kelvin scale of temperature? 1M

5. On converting 25°C, 38°C and 66°C to kelvin scale, the correct sequence of temperature will be:

a. 298 K, 311 K and 339 K

b. 298 K, 300 K and 338 K

c. 273 K, 278 K and 543 K

d. 298 K, 310 K and 338 K 1M

6. Convert:

(a) 27°C into kelvin scale (b) 500 K into Celsius scale 2M

7. What is dry ice? Dry ice is compressed at high pressure. What happens when pressure is released? 2M

8. Answer the following questions:

(a) Why is ice at 273 K more effective in cooling than water at the same temperature?

(b) Name the two gases which are supplied in compressed form in homes and hospitals. 2M

9. When a bottle of scent is opened in one corner of a room, it immediately spreads throughout the room. What property of matter is responsible for this observation? Explain 3M

10. Define (i) Latent heat of fusion and

(ii) Latent heat of vaporization.

(iii) Give suitable examples for (i) & (ii) 3M

11. What is Evaporation? Explain how the following factors affect the rate of evaporation of a liquid:

I. Temperature of the liquid. 3M

II. Area of the exposed surface.

III. Moisture in the surrounding air.

IV. Increase in wind speed.

Saturday, 12 August 2017

CLASS -8
FORCE AND PRESSURE WORKSHEET

Unit-11 FORCE AND PRESSURE

Q1) Fill in the blanks

a. A force arises due to __________ between two objects.

b. An example of a non-contact force is __________.

c. The pressure exerted by air around us is known as __________.

d. Strength of the force is expressed by its __________.

e. Application of force can change the __________, __________ and __________ of an object.

f. Force exerted by our muscles is called __________ force.

g. Direction of force of friction is always __________ to the direction of motion.

h. Force per unit area is called ___________.

Q2) Complete the following sentences:

a. If two equal forces act in the opposite directions on an object, the net force acting on it is __________.

b. It is easier to cut with a sharp knife than with a blunt one because ________________________ ____________________.

c. Porters place a round piece of cloth on their heads, when they have to carry heavy loads because __________________________________________________.

Q3) Give four effects of force. Write one example of each.

Q4) Name

a) the force exerted by all matter on all other matter

b) the force which tends to slow down objects or keep them from moving

c) the force with which a charged body attracts an uncharged body.

Q5) An example of a contact force is

1) Magnetic force

2) Frictional force

3) Gravitational force

4) All of these

Q6) A Force cannot change the

1) Speed of an object

2) Mass of an object

3) Shape of an object

4) The direction of a moving object

Q7) The pull of the earth is a force called

a) Gravitational force

b) Frictional force

c) Electrostatic forces

d) None of these

Q8) If a force is applied on a smaller area of contact, the pressure exerted by it is

1) Greater

2) Lesser

3) The same

4) None of these

CLASS -9 WORKSHEET

ITS MATTER AROUND US PURE

1. What are mixtures? Give examples.

2. What are pure substances?

3. Why do we call sugar a pure substance?

4. What are saturated and unsaturated solutions?

5. Define a solution.

6. What is a suspension? Give its example and properties.

7. Define concentration of a solution.

8. What is Tyndall effect?

9. What is the difference between True solution and colloids?

10. What are alloys? Why are alloys called as mixture?

11. Write the characteristics of brass.

12. Define solute and solvent.

13. What is solubility?

14. Give properties of a true solution.

15. Why do we need to separate mixtures?

16. How can we separate cream from milk?

17. Write the applications of centrifugation.

18. How can we separate a mixture of salt and ammonium chloride? Draw a diagram.

19. What is chromatography? Explain the process.

20. How can you separate copper sulphate from an impure sample?

21. What types of mixture are separated by fractional distillation process? Draw a diagram.

22. Draw a diagram to explain the process of separating acetone and water.

23. Explain with the diagram the method of separating kerosene oil from water by using a separating funnel.

24. What are physical and chemical changes?

25. Write difference between mixtures and compounds.

26. Give definitions of elements and compounds.

27. What are metals and non-metals?

28. If 110g of salt is present in 550 g of solution, calculate the concentration.

29. What is the concentration of a solution which contains 16 g of urea in 120 g of solutions?

30. How much water should be added to 15 g of salt to obtain 15% salt solution?

31. A solution contains 5.6 ml of alcohol mixed with 76 ml of water. Calculate the concentration of the solution.

32. How much water should be added to 12 ml of alcohol to obtain 12% alcohol solution?

33. If 25 ml of acetone is present in 150 ml of its aqueous solution, calculate the concentration.

CLASS-X WORKSHEET
METALS AND NON METALS

METALS AND NON-METALS

1. List five physical properties of metals and compare them with non-metals.

2. Why is gold widely used for making jewellery?

3. Name one metal commonly used for making cooking utensils. Give reason also.

4. Give exceptions in the following casesa.

a.All metals exist as solid at room temperature.

b. Non-metals are non-lustrous.

c. Non-metals do not conduct electricity.

d. Metals are hard.

e. Solid non-metals are brittle.

5. What is observed whena. Magnesium ribbon is burnt in a flame. (b) Copper metal is heated in air.

6. Name two metal oxides that are soluble in water. (Write equation also)

7. With the help of equations, show that Al2O3 is an amphoteric oxide.

8. Write equations for the reactions of an acid with:

a. Zn metal. (b) Na2CO3 (c) NaHCO3 (d) NaOH solution.

9. Why is there no evolution of hydrogen when nitric oxide reacts with metals?

10. What is the reactivity series of metals?

11. What is an electrovalent bond? Show the formation OF NaCl, Na2O, MgO and MgCl2 with the help of electrondot representation.

12. Why does a solution of sodium chloride conduct electricity which solid NaCl does not?

13. Write properties of ionic compounds.

14. Differentiate between a mineral and an ore.

15. Give reasons:

a. Gold and silver are found in their free state.

b. Sodium is never found in its free state.

c. The sulphide ore is converted into an oxide for the extraction of metals.

d. The oxides of metals like Hg can be reduced by heating only.

e. The oxides of metals like Na, Mg , Ca cannot be reduced by carbon

16. Name two metals that can be refined by electrolysis.

17. Name the cathode, anode and the electrolyte for refining of copper electrolytically.

18. Name the substance formed on the surface of iron, silver and copper due to corrosion.

19. How is steel different from stainless steel?

20. What is an alloy? Write the composition of brass, bronze and solder.