P-1 Carbon Compounds — Science STD 10 — Question

The surface of water in a lake appears green due to a layer of tiny free-floating organisms X on its surface. The lake water also contains organisms like water beetle, fish and tadpole. The sun shines over the lake water and provides energy for the functioning of this lake ecosystem.

1. What could organisms X be?
2. Write a food chain comprising of all the four organisms mentioned.
3. What is the general name of the food chains like the one written above?
4. Name (i) secondary consumer (ii) producer (iii) tertiary consumer, and (iv) primary consumer, in the above food chain.
5. If the tertiary consumer gets 0.2 J of energy from the secondary consumer, then how much energy was radiated by the sun to the producer?

When the solution of substance X is added to a solution of potassium iodide, then a yellow solid separates out from the solution:

1. What do you think substance X is likely to be?
2. Name the substance which the yellow solid consists of.
3. Which characteristic of chemical reaction is illustrated by this example?
4. Write a balanced chemical equation for the reaction which takes place. Mention the physical states of all the reactant and products involved in the chemical equation.

Write all the capital letters of the alphabet which look the same in a plane mirror.

Explain the need and importance of space missions.

How do the following change on going from left to right in a period of the periodic table?

1. Chemical reactivity of elements.
2. Nature of oxides of elements Give examples in support of your answer.

Observe the following diagram and answer the questions given below:


i. Identify the above diagram.
ii. Write the principle on which the above appliance works.
iii. write the working of the above appliance.
iv. Write the use of the above appliance.

The transport system in plants consists of two kinds of tissues X and Y. The tissue X is made up of living cells and consists of two components A and B. The component A has tiny pores in its end walls and contains only cytoplasm but no nucleus. On the other hand, component B has cytoplasm as well as nucleus. The tissue Y is made up of dead cells and consists of two components C and D. The component C has open ends whereas component D does not have open ends. In flowering plants, either only C or both C and D transport water but D is the only water conducting tissue in non - flowering plants.

1. What is (i) tissue X, (ii) component A and (iii) component B?
2. What is (i) tissue Y, (ii) component C and (iii) component D?

What will be the effect on yourself and surrounding, if any accident-like disaster occurs during the sports on playground or in school?