What are the advantages of nuclear energy?
The nuclear energy advantages are as follows:
a) Fusion of four hydrogen atoms produces a huge amount of energy approximately equal to 27 MeV.
b) Large amount of energy is produced per unit mass.
c) It does not produce smoke. It is clean energy.
d) Fission of one atom of uranium produces 10 million times the energy released by burning of one atom of carbon.
Can any source of energy be pollution-free? Why or why not?
What are the limitations of the energy that can be obtained from the oceans?
If you could use any source of energy for heating your food, which one would you use and why?
On what basis would you classify energy sources as
(a) renewable and non-renewable?
(b) exhaustible and inexhaustible?
Are the options given in (a) and (b) the same?
What is a good source of energy?
Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG? Why or why not?
Which of the following is not an example of a bio-mass energy source?
(a) wood (b) gobar-gas
(c) nuclear energy (d) coal
What are the disadvantages of fossil fuels?
Name two energy sources that you would consider to be renewable. Give reasons for your choices.
Compare and contrast fossil fuels and the Sun as direct sources of energy.
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
How is the amount of urine produced regulated?
How many 176 Ω resistors (in parallel) are required to carry 5 A on a 220 V line?
Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4.
Which of the following groups contain only biodegradable items?
(a) Grass, flowers and leather
(b) Grass, wood and plastic
(c) Fruit-peels, cake and lime-juice
(d) Cake, wood and grass
Which of the following statements is not a correct statement about the trends when going from left to right across the periods of periodic Table.
(a) The elements become less metallic in nature.
(b) The number of valence electrons increases.
(c) The atoms lose their electrons more easily.
(d) The oxides become more acidic.
Give a test that can be used to differentiate between saturated and unsaturated hydrocarbons.
Give an example of a metal which
(i) is a liquid at room temperature.
(ii) can be easily cut with a knife.
(iii) is the best conductor of heat.
(iv) is a poor conductor of heat.
Translate the following statements into chemical equations and then balance them.
(a) Hydrogen gas combines with nitrogen to form ammonia.
(b) Hydrogen sulphide gas burns in air to give water and sulpur dioxide.
(c) Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
(d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
Explain different ways to induce current in a coil.
Explain the nature of the covalent bond using the bond formation in CH3Cl.