1) Fill in the blanks with the words given below:

Condensation is the opposite of ……………………………………… . It is the changing of a ……………………………………… into a liquid. This happens when the ……………………………………… of a gas drops to a certain point. Examples of condensation are ……………………………………… onto a cold surface which makes it go “misty”.

(Warmer, breathing , temperature, steam , breeze, liquid , evaporation, gas)

2) Equal amount of water in two separate containers is heated up to 20.8oC and 46.3oC. What will be the final temperature if the water in the two containers mixed together?

3) Name the types of chemical decomposition reactions and mention the number of reactant(s) in this type of reaction

4)What is meant by Oxidation? How do you prevent domestic articles made of Iron from Oxidation?

5) Solution X turns red litmus to blue,while another solution Y turns blue litmus to red.

(a)When X and Y are added,what are the products likely formed?

(b)What are the reactions of X and Y with olfactory indicators ?

(c) What is the metal that reacts with both X and Y ?

6) 12 K.cal.of heat is supplied to 2Kg. of Iron. The initial temperature of Iron is 200C.The specific heat capacity of Iron is 0.1Cal/g-0C.Find the final temperature of Iron.

7) The warning label as shown in the figure appears on some containers of acids and bases. What does it tell us about the nature of those acids and bases?

8) What happens when an acid or a base is added to the water? Why does the beaker appear warm? Why should we always add acid or base to the water and not water to the acid or base.

One mark

9) What is this instrument called ? How is it useful?

10) The temperature recorded by a thermometer decreases when its bulb is covered with a

Piece of cloth soaked in spirit.Why?

11) All alkalis are bases,but not all bases are alkalis .Explain.

12) Give an example each (i) Strong acid (ii) weak base

13) Mention the common names of Ca(OH)2 and Na2CO3

14) In terms of energy how can you classify photosynthesis and respiration?

4 marks

15) P and Q are two substances. Their temperatures at different instances are given in the table below.Read the table and answer questions given.

a) At which instances, the substances are at thermal equilibrium?

b) At which instances, the flow of heat energy is from P to Q ?

c) At which instances, heat flows from Q to P?

d) What are the conditions required for transfer of heat energy?

Instance A B C D E

Substance P 300C 500C -2730C 10K 30K

Substance Q 300C 300C 0K 200C 300C

16) Fill in the table with required information regarding acids, bases and neutral solutions.

17) Answer the following questions with the help of the diagram given .

a) why does water vapour at 1000C cause more severe burns than water at 1000C ?

b) How much heat is required to convert one gram of ice at 00C to water at 00C ?

c) What is meant by latent heat?

d) what is the difference between freezing and melting?

18) As a part of project work,Raju of class 10,was given two samles of solutions . His teacher told him that out of the two, one sample was distilled water and the other , acidified water. Raju’s task was to identify them by way of conducting electricity .His arrangement of apparatus is shown in the picture.Now answer the given questions.

a) In which set up electricity is flowing through the solution?

b) Name b,d,e in the diagram.

c) Name c and f (solutions)

d) Explain why the bulb is not glowing in set up (1) .Give reason.

19) (a) Write down four products formed with the help of common salt on industrial level. (b) Write down the chemical name of these compounds and one use of each of them.

20) How do you appreciate the following in our daily lifewith one example each?

a) High specific heat capacity of water b) Neutralisation c) oxidation reactions d) evaporation and condensation

21) You are supplied with the following material and substances and asked to demonstrate the different types of chemical reactions.( Copper sulphate,Barium chloride,Ferrous sulphate , Iron nails,Quick lime and water.) How do you demonstrate?

22) Look at the given picture.Basing on the statement made by the girl, list out the differences between a physical and a chemical change

5 marks

23)Draw a labelled diagram to show how acids react with metals. Write the balanced equation of the reaction. How do you test the gaseous product in this reaction?

24)Suggest an experimental setup to demonstrate transfer of heat from hotter substance to colder substance with a labeled diagram. Mention one precautionary measure to be taken, while conducting the experiment.

Solution PH H+ OH-

Acid

Base

Neutral

Part B

1) In Lays, Kurkure packets chips can be protected for long time. The gas used in thesepockets is ( )

a) Oxygen b) Nitrogen c) Hydrogen d) Carbondioxide

2) Which of the following is not correct . ( )

a) No heat transfer takes place between the bodies of the system, if the system is at thermal equilibrium.

b) The boiling temperature of water increases with the increase in pressure.

c) The kinetic energy of the molecule is zero when the liquid is at o °C

d) 80000cal of heat is required for 1 kg ice at 0°C to becoming water.

3) Which of the following are exothermic processes?

(i) Reaction of water with quick lime(ii) Dilution of an acid (iii) Evaporation of water (iv) Sublimation of camphor (crystals)

(a) (i) and (ii) (b) (ii) and (iii) (c) (i) and (iv) (d) (iii) and (iv)

4) Which of the following are the characteristics of a chemical reaction:

(a) Evolution of gas (b) formation of precipitate (c) change in color (d) all

5)Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is

(a) 1:1 (b) 2:1 (c) 4:1 (d) 1:2

6) Which one of the following processes involve chemical reactions?

(a) Storing of oxygen gas under pressure in a gas cylinder (b) Liquefaction of air (c) Keeping petrol in a china dish in the open (d) Heating copper wire in presence of air at high temperature

7)Sodium carbonate is a basic salt because it is a salt of

(a) strong acid and strong base (b) weak acid and weak base (c) strong acid and weak base

(d) weak acid and strong base

8)Which of the following gives the correct increasing order of acidic strength?

(a) Water <Acetic acid <Hydrochloric acid (b) Water <Hydrochloric acid <Acetic acid

(c) Acetic acid <Water <Hydrochloric acid (d) Hydrochloric acid <Water <Acetic acid

9)If a few drops of a concentrated acid accidentally spills over the hand of a student, what should be done?

(a) Wash the hand with saline solution (b) Wash the hand immediately with plenty of water and apply a

paste of sodium hydrogencarbonate (c) After washing with plenty of water apply solution of sodium

hydroxide on the hand (d) Neutralise the acid with a strong alkali

10)Which of the following phenomena occur, when a small amount of acid is added to water?

(i) Ionisation (ii) Neutralisation (iii) Dilution (iv) Salt formation

(a) (i) and (ii) (b) (i) and (iii) (c) (ii) and (iii) (d) (ii) and (iv)

Fill in the blanks.

11) The hotness of an object is determined by its --------------------

12) C.G.S. unit of heat is --------------------

13). The temperature at which a substance changes from a solid to a liquid is best described as the _______________.

14) 800 g of water are warmed from 100 C to 800 C. The energy absorbed in J is ---------------------

15) One of the primary reasons that water changes temperature more slowly than soil or rock is because of its higher

----------------------------------------

16) --------------- is used as coolant.

17) The sultryness in summer is due to---------------

18) The average kinetic energy of the molecules is directly proportional to the ------------------

19)----------------------- is the reverse process of evaporation.

20)If you wanted to warm up a swimming pool of water you need heat energy. Here are two methods for warming the water. The best method is -------------------- ( Warm the water with a teacup of water at 100°C / Warm the water with a bucket of water at 50°C)

Match the following:

21) Heat A) water vapour in air

22) Temperature B) JKg-1-K

23) Specific heat capacity C) Joule

24) Latent heat D) J/Kg.

25) Humidity E) Kelvin

6) Na2CO3 A)CaSO4,1 / 2 H2O

27)Cu SO4 B) 10 H2O

28) CaSO4 C) Nettle plant

29) Plaster of paris D) 2 H2O

30) Methanoic acid E) 5 H2O