Answer the following questions as directed: (Each question carries 1 mark) [4]
Q-1 Fill in the blanks with suitable word:
1. The formula for ozone is _______
a. O2 b. O4 c. O3 4. 2O
Q-2 What is atom ?
Q-3 Choose the right answer:
Which one is an oil yielding plant among the following?
(a) Lentil (b) Sunflower (c) Cauliflower (d) Hibiscus
Q-4 Find out the correct sentence:
(i) Hybridization means crossing between genetically dissimilar plants
(ii) Cross between two varieties is called as inter specific hybridization
(iii) Introducing genes of desired character in to a plant gives genetically modified crop
(iv) Cross between plants of two species is called as inter varietal hybridization
(a) (i) & (ii) (b) (ii ) & (iv) (c) (ii ) & (iii) (d) (iii ) & (iv)
Section-B
Answer the questions point wise: (Each question carries 2 mark) [8]
Q-5 What is a molecule ? Explain.
Q-6 State and explain the law of conservation of mass along with an example.
Q-7 Why is excess use of fertilizers detrimental for environment?
Q-8 What is genetic manipulation ? how is it useful in agricultural practices ?
Section-C
Answer the Following questions as required: (Each question of 3 marks) [9]
Q-9 Write any three name of the following compounds .
i. Al2(SO4)3 ii. CaCl2 iii. K2SO4 iv. KNO3
Q-10 What are weeds? Give the examples of weeds, need to control them and methods to control them.
Q-11 How do you differentiate between capture fishing ,mariculture and aquaculture ?
Section-D
Answer the Following question [4]
Q-12 State the postulate of Dalton’s theory.
Answers
A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place". Examples commonly are plants unwanted in human-controlled settings, such as farm fields, gardens, lawns, and parks. ... In the same way, volunteer crops (plants) are regarded as weeds in a subsequent crop.
1. The formula for ozone is O2
Q-2 What is atom ?
Ans- An atom is the smallest particle into which an element can be divided without losing its chemical identity. Atoms consist of a heavy central nucleus surrounded by a cloud of negatively charged particles called electrons. The nucleus contains positive particles (protons) and electrically neutral particles (neutrons).
Q-3 Choose the right answer:
Which one is an oil yielding plant among the following?
Ans- . the correct answer is Sunflower
Q-4 Find out the correct sentence:
Ans-
(i) Hybridization means crossing between genetically dissimilar plants
Q-5 What is a molecule ? Explain.
Ans-
Molecule, a group of two or more atoms that form the smallest identifiable unit into which a pure substance can be divided and still retain the composition and chemical properties of that substance.
A molecule is a particle made up of two or more atoms that are chemically bonded together; the number of atomic nuclei making up a molecule is a determinate number. For example, HCl(g) is a molecule made of one hydrogen atom bonded to one chlorine atom
Q-6 State and explain the law of conservation of mass along with an example
ANS-
State the Law of Conservation of Mass with Example
Law of Conservation of Mass Examples
Chemical reactions: To get one molecule of H2O (water) with the molecular weight of 10, Hydrogen with molecular weight 2 is added with Oxygen whose molecular weight is 8, thereby conserving the mass.
The law of conservation of mass states that matter cannot be created or destroyed in a chemical reaction. For example, when wood burns, the mass of the soot, ashes, and gases equals the original mass of the charcoal and the oxygen when it first reacted. So the mass of the product equals the mass of the reactant
Q.7
Why is excess use of fertilizers detrimental for environment?
Ans-
Answer: Fertilisers are inorganic chemicals which are not easily degraded. Excess use of fertilisers causes environmental pollution as their residual and unused amounts will become pollutants for air, water and soil.
Q-8 What is genetic manipulation ? how is it useful in agricultural practices ?
Ans: Genetic manipulation is a process in which genes of desirable characters are taken from a plant and transferred to another plant by the technique of hybridisation. Genetic manipulation helps in obtaining desirable agronomic characters liked Dwarfness in cereals and tallness and profuse branching in fodder crops