| Chemical Reactions and Equations | - a) Define Rusting.
b) Why do you apply paint on iron articles? - White the balanced reactions for the following:
a) Potassium Bromide(aq)+Bariumiodide(aq) → Potassium iodide(aq)+BariumBromide(bq)
b) Zinc carbonate(s) Zincoxide(s)+carbondioxide(g)
c) Hydrogen(g)+chlorine(g) → Hydrogen chloride -
The reaction is given by Zn+H₂SO→ ZnSO4+H₂
i. White the ionic equation for the reaction.
ii. The ionic equations can be represented by two half equations. Write these equations.
iii. Explain why this is a redox reaction. - What are neutralization reactions? Why are they named so? Give one example?
- Identify the type of reaction in the following
a) ZnCO3 + 2HCl (aq) → ZnCl2 (aq) + H2CO3 (aq)
b) 2NaBr (aq) + Cl (g) → 2NaCl (aq) + Br2 (aq)
c) 2CuO (s) Heat2Cu (s) + O2 (g) |
| Acid Bases and Salts | - (a) Name the raw materials used in the manufacture of sodium carbonate by the Solvay process?
(b) How is sodium hydrogen carbonate separated from a mixture of NH4Cl and NaHCO3 - Write equations for the following reactions
a) Dilute sulphuric acid reacts with zinc granules
b) Dilute hydrochloric acid reacts with magnesium ribbon.
c) Dilute sulphuric acid reacts with aluminium powder. - a) An aqueous solution has a pH value of 7.0 Is this solution acidic, basic, or neutral?
b) If H+ concentration of a solution is 1 x 10-2 mol L¹ what will be its pH value?
c) Which has higher pH value: 1 M HCl or 1-M NaOH? - What will you observe when:
a) Red litmus is introduced into a solution of sodium sulphate.
b) Methyl orange is added to dil HCl
c) Blue litmus is introduced into a solution of ferric chloride - A first aid manual suggests that vinegar should be used to treat wasp sting and baking soda for bee stings.
a) What does this information tell you about the chemical name of the wasp sting?
b) If there were no baking soda in the house, what other household substances would you use to treat as stings? |
| Metals and Non-metals | -
Arrange the following metals in decreasing order of their reactivity: a) Cu, Ca, Mg, Na, Zn
b) You are provided with three metals: sodium, magnesium, and copper. Using only water as the reactant, how will you identify each of them?
c) Which metal listed in (a) is most likely to occur in the native state? -
Which method of concentration of ore is preferred in the following cases and why?
a) The ore has higher-density particles mixed with a large bulk of low-density impurities.
b) The ore consists of copper sulphide intermixed with clay particles.
c) Give an example of amalgam. -
a) Why is ZnO called an amphoteric oxide? Name another amphoteric oxide.
b) What are alkalis? Give one example of an alkali. -
You are given a hammer, a battery, a bulb, wires, and a switch.
a) How could you use them to distinguish between samples of metals and non-metals?
b) Assess the usefulness of these tests to distinguish between metals and non-metals. -
Name an alloy of
(i). Aluminium is used in the construction of aircraft.
(ii). Lead is used in joining metals for electric work.
(iii). Copper is used in household vessels. |
| Carbon and Its Compounds | - What is the role of concentrated sulphuric acid in the esterification reaction?
- What will be the formula and electron dot structure of cyclopentane?
- Draw the structures of the following compounds a) Ethanoic acid b) Bromopentane c) Butanone
- Give names of the following
a) An aldehyde derived from ethane
b) Ketone derived from butane
c) The compound obtained by the oxidation of ethanol by chromic anhydride - What is meant by denatured alcohol? What is the need to denature alcohol?
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| Life Processes | - What are the functions of lymph in our body?
- How is haemoglobin associated with respiration explained?
- What are the modes of excretion in plants?
- Give an experiment to prove the essentiality of light for photosynthesis.
- What is “translocation”? Why it is essential for plants.
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| Control and Coordination | - Mention three important functions of gibberellins.
- What is the function of receptors in our body? What happens when receptors do not work properly?
- What happens at the synapse between two neurons?
- What is the need for a system of control and coordination in an organism?
- The pituitary is a master endocrine gland. Justify this statement.
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| How do Organisms Reproduce? | - What changes occur in girls and boys in the age group of 10 -14 years?
- Describe sexually transmitted diseases (STDs) and mention the ways to prevent them.
- Name the surgical methods of birth control in human males and females respectively.
- What are the essential requisites for sexual reproduction?
- What is micropropagation? Mention its advantages.
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| Heredity | - Only variations that confer an advantage to an individual organism will survive in a population. Do you agree with this statement? Why or why not?
- What are the different approaches to determining the evolutionary history of man?
- What is fossilization? How are fossils formed?
- What are homologous and analogous organs? Explain with the help of an example.
- Differentiate between convergent and divergent evolution.
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| Human Eye and Colourful World | -
Explain in brief:
a) What is hypermetropia?
b) What are the two causes of this defect of vision? - Explain the scattering of light?
- What is presbyopia? State the causes of this defect. How is the presbyopia of a person corrected?
- Why do stars twinkle?
- A reporter records the following observations of an astronaut from his spaceship. Justify each statement.
a) The length of the day is the same as observed on the earth.
b) Space appears black.
c) The star appears to twinkle while the planets do not do so as they do on the earth. |
| Electricity | - Two metallic wires A and B are connected, wire A has length I and radius r, while wire B has length 2l, and radius 2r. Find the ratio of the total resistance of the series combination and the resistance of wire A, if both the wires are of the same material.
- Two resistors of resistance R and 2R are connected in parallel in an electric circuit. Calculate the ratio of the electric power consumed by R and 2R.
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Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then in parallel in an electric circuit. the ratio of heat produced in series and parallel combinations would be (a) 1:2
(b) 2:1
(c) 1:4
(d) 4:1 - How much energy is given to each coulomb of charge passing through a 6-volt battery?
- On what factor does the resistance of a conductor depend?
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| Magnetic Effects of Electric Current | - What is the function of an earth wire? Why is it necessary to earth the metallic casing of electric appliances?
- We know a current-carrying conductor placed in a magnetic field experiences a force due to which the conductor moves. How do we think the rod displaces if
a) the current in the rod is increased
b) a stronger horseshoe is inserted
c) The length of the rod is increased - What is the principle of the electric motor?
- State three factors on which the magnetic field produced by a current-carrying solenoid depends.
- What is a solenoid? Draw magnetic field lines showing the magnetic field inside and outside the current-carrying solenoid?
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| Our Environment | - DDT that was sprayed in minute amounts on food plants was detected in high concentrations in humans. How did it happen? Explain.
- Describe how the ozone layer is formed.
- What are the major components of the environment?
- Why are some substances biodegradable and some non-biodegradable?
- Explain why a food chain consists of a few steps only. Write a food chain having five steps.
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