Question

4. What is the chemical formula of plaster of paris?

5. What is the pH value of water?

6. Which part of the brain maintains posture and equilibrium of the body?

Answer the following questions in 20 to 30 words:

7. Why is respiration called an exothermic reaction?

8. Why does distilled water not conduct electricity, where as rainwater does?

9. The marble statues are often slowly corroded when kept inn open for a long time. Give reason.

10. What is the difference between a reflex action and walking?

11. What are plant hormones?​

Answer 1

Explanation:

4. Plaster of Paris is also referred to as Gypsum plaster. The chemical formula of plaster of Paris is written as CaSO4·H2O or 2CaSO4·H2O.

5. The pH of most drinking-water lies within the range 6.5–8.5

6. The part of the brain responsible for maintaining posture and equilibrium of the body is the cerebellum.

7. Carbolydrates present in food are broken down to form glucose. This glucose combines with oxygen in the cells of our body and provides energy. This reaction is known as respiration. hence,respiration is considered as an exothermic reaction.

8. Distilled water is a pure type of water which does not contain any ions in it. ... These gases dissolve in water to form some kind of acids like carbonic acids which dissociates to give ions. Thus rainwater is conducting electricity while distilled water is not conducting electricity.

9. The marble statues often slowly get corroded when kept in air for a long time. This is because the marble does react with the acidic compounds which are present in the air, like carbonic acid, sulphuric acid and nitric acid etc. ... This also leads to the acid rain.

10. A reflex action is an involuntary action that is a rapid and automatic response to stimuli.

Walking is a voluntary action, which requires our thinking and is within our control.

11. Plant hormones (also known as phytohormones) are signal molecules, produced within plants, that occur in extremely low concentrations. ... Unlike in animals (in which hormone production is restricted to specialized glands) each plant cell is capable of producing hormones.

Answer 2

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What is the chemical formula of plaster of paris?

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• The chemical formula for the plaster of Pāris is (CaSO4) H2O

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What is the pH value of water?

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• The pH of møst drinkïng-wāter lies within the rānge 6.5–8.5.

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Which part of the brain maintains posture and equïlibrium of the body?

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• Cerëbellum

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Why is respiration called an exóthermic reaction?

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• Any reaction that evølves heat as a by-product of the reaction is called an exøthermic reaction.
• Therefore, respiration is an exøthermic reaction and the heat produced is distributed throughout the body as energy and that is the reason when we breāthe out or breāth is warm.

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Why does distïlled water not conduct electricity, where as rainwāter døes?

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• Dïstilled water is a pure type of water which does not contain any ions in it.
• These gases dissølve in water to form some kind of acids like carbønic acids which dissociates to give ions.
• Thus rainwater is conducting electricity while distïlled water is not conducting electricity.

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The marble statues are often slowly corrøded when kept inn open for a long time. Give reason.

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• The marble statues often slowly get corrøded when kept in air for a long time.
• This is because the marble does react with the acïdic compounds which are present in the air, like carbonic acid, sulphüric acid and nitric acid etc.
• This also leads to the acïd rain.

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What is the difference between a reflëx action and walking?

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• A reflëx action is an involuntary and nearly instäntaneøus movement in response to a stimulus
• While ; Walking is a voluntary action, which requires our thinking and is within our control.

• Reflëx action is a spontaneous or rapid involuntary act
• While walking is a voluntary action

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What are plant hormones?

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1. Plant hormones are simple organic substances transported through xylem, phloem or by diffusion.

• They are produced in one part of the plant and transported to the other. No specific organs are involved in the synthesis of the plant hormones.

• Plant hormones include auxin, abscisic acid, ethylene, gibberellins, cytokinins, salicylic acid, strigolactones, brassinosteroids, and nitrous (nitric) oxide.