chemical bonding and acid base

CHEMICAL BONDING & dr ACIDS, BASES SALTS

1.      From the following list of substances choose the one substance in each case which matches the description (i) to (vi) given below:

Ammonium nitrate, calcium hydrogen carbonate, copper carbonate, lead carbonate, lead nitrate, potassium nitrate, sodium carbonate, sodium hydrogen carbonate, zinc carbonate.

                                i.            A hydrogen carbonate which exists in the solid state.

                              ii.            A carbonate not decomposed by heat.

                            iii.            A nitrate which gives off only oxygen when heated.

                            iv.            A nitrate which on heating decomposes into dinitrogen oxide and steam.

                              v.            A nitrate which gives off oxygen and nitrogen dioxide when heated.

2.      State what you observe when :

1. Neutral llitmus solution is added to an alkaline solution.

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2. Lead nitrate solution and sodium chloride solution are mixed.

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3.      Mention the terms defined by the following sentences:

1. A soluble base
2. An acidic solution in which there is only partial ionization of the solute molecules
3. The insoluble solid formed when two solutions are mixed together

4.      Write the equations for the laboratory preparation of:

1. Sodium sulphate using dilute sulphuric acid

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2. Lead sulphate using sulphuric acid.

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5.      If HS is a weak acid, what particles will be present in its dilute solution apart from those of water?

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6.      Write balanced equations for the following reactions:

1. Lead sulphate from lead nitrate solution and dilute sulphuric acid.

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2. Copper sulphate from copper and concentrated sulphuric acid.

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3. Lead chloride from lead nitrate solution and sodium chloride solution.

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4. Ammonium sulphate from ammonia and dilute sulphuric acid.

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5. Sodium chloride from sodium carbonate solution and dilute hydrochloric acid.

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7.      Name the charged particles which attract one another to form electrovalent compounds.

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8.      Electrons are getting added to an element Y:

1. Is Y getting oxidized or reduced?
2. What charge will Y have after the addition of electrons?
3. Which electrode will Y migrate to during the process of electrolysis?

9.      Draw an electron dot diagram of a hydronium ion and label the lone pair of electrons.

10.  In the formation of magnesium chloride name the substance that is oxidized and the substance that is reduced.

11.  State two differences you would expect to find between the properties of carbon tetrachloride and sodium chloride.

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12.  Give the reason why ionic compounds have high melting point and boiling  point.

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13.  State which of the following are oxidized or reduced:

1. N  -à N^3-
2. Cl^- àCl₂
3. Cu  à Cu²⁺
4. Cr  à Cr³⁺

14.  Element X is a metal with a valency 2.  Element Y is a non metal with a valency 3.

1. Write equations to show how X and Y form ions.

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2. If Y is a diatomic gas, write the equation for the direct combination of X and Y to form a compound.

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15.  Explain the following briefly:

1. Helium does not form He₂  molecule.

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2. Metals are electropositive.

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Biology class 10 ICSE Absorptions - Photosynthesis

Fill in the blanks

1.     Loss of water as droplets through leaves of an intact plants is termed as_____________

2.     Transpiration is the loss of water as water______________from the _____________parts of the plants

3.     Closing of ___________and shedding of leaves reduces ______________

4.     Transpiration helps in creating ______________force and in eliminating excess ____________

5.     Transpiration is different from evaporation because it basically involves vital _____________ processes.

6.     Transpiration taking place by evaporation from the epidermal cells through the cuticle is known as ___________transpiration

7.     The site of light reaction in the cells of a leaf is _______________

8.     The chemical substance used to test the  presence of  starch in the cell of a leaf is _______________

9.     In the flowering plants, food is transported in the form of ___________

10.                        The dark reaction of photosynthesis is known as ___________

11.                        Stroma is ground substance in ____________

12.                        CO2 enters the leaf through_________________

13.                        Xanthrophyll  is __________colored pigment

14.                        Photosynthesis produces __________and ____________

15.                        Land plants obtain their carbon dioxide from ______________

16.                        ____________ is the process which replenishes the atmospheric oxygen which the animal life consumes in respiration .

17.                        All animals on Earch would die if there was no_____________

Maths- Worksheet class7

1.      How many litres are there in 755 ml ? 

2.      By what number should  be divided to get.  

3.      Rectangular sheet of paper is 12 ½ cm long and cm wide. Find its perimeter

4.      Find the missing Numerator

(a) 3 8 = ? 72

(b) 5 8 = ? 16

        5. Fractions division, Substraction and multiplication

a) 1 4 ÷ 6 8 =

b) 8 20 × 7 30 =

6.      Addition and subtraction of decimals

a.    260.6 − 2.01 = _________

b.    519.45 + 34.52 = _________

6.       State the property that is used in each of the following statements

a) <1=<5    b)  <3=<5      c)<4=<6

d) Write Alternate angle of <2        e)Write corresponding angle of <7

7.       Kim can walk 4 kilometers in one hour. How long does it take Kim to walk 18 kilometers?