During an exothermic reaction

Which of the following salts has no water of crystallization?

If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of

The kidneys in human beings are a part of the system for

Which statement is not true about thyroxin?

A cylindrical conductor of length l and uniform area of cross section A has resistance R, another conductor of length 2l and resistance R of the same material has area of cross section?

The magnetic field inside a long straight current carrying solenoid

The major problem in harnessing nuclear energy is how to?

A molecule of ammonia (NH₃) has

On moving from left to right in a period in the periodic table, the size of the atom.

What happens when ZnCO₃ is heated in the absence of air? Give the relevant equation.

A compound ‘X’ is used for drinking has pH=7. Its acidified solution in presence of electricity undergoes decomposition to produce gases ‘Y’ and ’Z’. The volume of ‘Y’ is double than ‘Z’.’Y’ is highly combustible whereas ‘Z’ is a supporter of combustion. Identify ‘X,’Y, ’Z’ and write the chemical reactions involved.

A metal nitrate solution ‘A’ is added to reddish brown metal ‘B’. The metal present in ‘A’ is used for making jewellery and turns black in air, very thin foils of metal are used to decorate sweets. The compound ‘C’ formed on chemical reaction is blue in color and metal present in ‘A’ is formed. Identify A’ ‘B’ and ‘C’ and write chemical reactions involved.

Dry ammonia gas has no action on litmus paper, but a solution of a ammonia in water turns red litmus paper blue, why is it so?

Which gas is usually liberated when an acid reacts with a metal?

What seems to happen when a piece of sodium metal is dropped into water?

Name three common types of ores where metal exists in nature.

Give an example of a metal which is the best conductor of heat.

Why is respiration considered an exothermic process?

What is meant by 'translocation' with respect to transport in plants?

What is breathing?

What are olfactory receptors?

Write the components of central nervous system.

What are photoreceptors?

What is meant by the statement, "Potential difference between points A and B in an electric field is 1 volt"?

Give the unit of power.

A wire of resistance 10 ohm is bent in the form of a closed circle. What is the effective resistance between the two points at the ends of any diameter of the circle?

What kind of quantity is magnetic field?

Where do we connect a fuse with the live wire or with neutral wire?

Name the rule used to determine the direction of induced current.

What is a nuclear reactor?

What is energy?

What are fossil fuels?

Draw the structure of CH₃COOH molecule.

Name the functional group present in each of the following organic compounds:
(i) C₂H₅Cl
(ii) C₂H₅OH

Write the name and structure of an alcohol with four carbon atoms in its molecule.

Lithium, sodium and potassium form a Dobereiner's triad. The atomic masses of lithium and potassium are 7 and 39 respectively. Predict the atomic mass of sodium.

Why was the system of classification of elements into triads not found suitable? 

How many vertical columns are there in the modern periodic table and what are they called?

Give an example of a decomposition reaction. Describe an activity to illustrate such a reaction by heating.

Two solutions A and B have pH values of 5 and 8 respectively.  Which solution will be basic in nature?

Name two metals that start floating after sometime when immersed in water and explain why they do so.

How is the small intestine designed to absorb digested food?

List in tabular form three differences between nervous control and chemical control.

Answer the following:
(a) Define electric power.
(b) Give the commercial unit of electrical energy.
(c) Derive the relation between electric power with joule.

A compass needle is placed near a current-carrying wire. State your observation for the following cases and give reason for the same in each case:
(a) Magnetic of electric current in the wire is increased.
(b) The compass needle is displaced away from the wire.

Mention any two limitations of using fossil fuels.

How will you detect the presence of unsaturated compounds and saturated compounds using bromine in carbon tetrachloride? Give reactions involved.

What physical and chemical properties of elements were used by Mendeleev in creating his periodic table? List two observations which posed a challenge to Mendeleev's Periodic Law.

What happens when:
(i) Dilute hydrochloric acid is added to solid sodium carbonate.
(ii) Quicklime is treated with water.
(iii) Sodium chloride solution is added to lead nitrate solution.
Also write the chemical equation in each case.

Write the chemical equation of the reaction with an example each in which the following change has taken place:
(i) Change in colour
(ii)Change in temperature
(iii) Formation of precipitate.

What happens when the solution of baking soda is heated? Write the chemical equation for the same. Name the product which is responsible for making the bread or cake spongy and fluffy.

Mention the products produced when an acid reacts with a base. Give equation of an example of the reaction involved. What is this kind of reaction known as?

(i) A non-metal X exists in two different forms Y and Z. Y is the hardest natural substance whereas Z is a good conductor of electricity. Identity X, Y, Z.
(ii) A element, X, on reaction with oxygen forms an oxide XO₂. The oxide when dissolved in water turns blue litmus red. State whether element X is a metal or a non-metal.
(iii) Name the metal which is alloyed with copper to make bronze.

You are given samples of three metals: Sodium, magnesium and copper. Suggest any two activities to arrange them in order to their decreasing reactivity

How are oxygen and carbon dioxide transported in human beings? How are lungs designed to maximize the area for exchange of gases?

Give reasons for the following:
(i)The glottis is guarded by epiglottis
(ii)The lung alveoli are covered with blood capillaries.
(iii)The wall of trachea is supported by cartilage rings.

Draw a diagram of human brain and label on it the following of its parts:
(i) Cerebrum
(ii) Meninges
(iii) Medulla Oblongata
(iv) Cerebellum

Distinguish between voluntary and involuntary actions of our body.

Two lamps, one related 60W at 220 W at 220V and the other 40 W at 220 V, are connected in parallel to the electric supply at 220V.
(a) Draw a circuit diagram to show the connections.
(b) Calculate the current drawn from the electric supply.
(c) Calculate the total energy consumed by the two lamps together when they operate for one hour.

Give differences between conductors and insulators.

(a) What are 'magnetic field lines'? How is the direction of a magnetic field at a point determined?
 (b) List any three properties of magnetic field lines.
 (c) Draw two field lines around a bar magnet along its length on its two sides and mark the field directions on them by arrow marks.

Distinguish between an electric motor and generator?

(a) Why is the Solar Cooker box covered with a plane glass plate?
(b) Why is energy of water flowering in a river considered to be an indirect form of solar energy?
(c) How is the fission of nucleus brought about?

(a) State one limitation of solar energy available from solar cells.
(b) What is the minimum wind velocity required to obtain useful energy with a windmill?
(c) Define the term 'nuclear fission'.

What happens when a piece of
(a) Zinc metal is added to copper sulphate solution?
(b) Aluminium metal is added to dilute hydrochloric acid?
(c) Silver metal is added to copper sulphate solution? Write the balanced chemical equation if the reaction occurs.

A sulphate salt of Group 2 element of the Periodic Table is a white, soft substance.  Which can be moulded into different shapes by making its dough.  When this compound is left in open for sometime, it becomes a solid mass and cannot be used for moulding purposes.  Identify the sulphate salt and why does it show such a behaviour?  Give the reaction involved.

Of the three metals X, Y and Z, X reacts with cold water, Y with hot water and Z with steam only. Identify X, Y and Z and also arrange them in order of increasing reactivity.

Define the terms 'nutrients' and 'nutrients'.List two differences between 'Holozoic nutrition' and 'Saprophytic nutrition'.Give two examples of each of these two types of nutrition.

Mention one function for each of these hormones:
(a) Thyroxin
(b) Insulin
(c) Adrenaline
(d) Growth hormone
(e) Testosterone

How will you infer with the help of an experiment that the same current flows through every part of the circuit containing three resistances in series connected to a battery?

Describe the activity that shows that a current-carrying conductor experiences a force perpendicular to its length and the external magnetic field. How does Fleming's left-hand rule help us to find the direction of the force acting on the current carrying conductor?

(i) Write the value of solar constant of Sun.
(ii) What type of mirror is used in Box Type Solar Cooker?
(iii) Why it is difficult to use hydrogen as a source of energy?
(iv) Fossil fuels are classified as non-renewable source of energy. Explain why.

State the reason why carbon can neither form C⁴⁺ cations for C^4- anions, but forms covalent compounds. Also state reasons to explain why covalent compounds:
(a) are bad conductors of electricity?
(b) have low melting and boiling points

Atomic number of a few elements are given below 10, 20, 7, 14
(a) Identify the elements.
(b) Identify the Group number of these elements in the Periodic Table.
(c) Identify the Periods of these elements in the Periodic Table.
(d) What would be the electronic configuration for each of these elements?
(e) Determine the valency of these elements.