Question

Today's Homework
Subject: Chemistry
1) What is produced when limestone is heated?
2) What is the name of the reaction when both oxidation and reduction occur at a time?
3) Silver Chloride turns grey in sunlight. What kind of reaction is this?
4) What is the chemical formula of Copper Sulphate?
5) Which gas is added in food packets, such as pack of chips to avoid them from getting rancid?
6) What is produced in a precipitation reaction?
7) The decomposition of vegetable matter into compost is an example of which reaction?
8) What is produced when sulphuric acid is added to Zinc granules?
9) What is the colour of the fumes when Lead Nitrate powder is heated?
10) What is the reaction called when there is a loss of Oxygen and gain of Hydrogen?
11) What is the phenomenon of oxidising of fats and oils called?
12) Which of the following is not an exothermic reaction?
A. Photosynthesis B. Respiration C. Burning of coal D. Sunlight on Silver Chloride
Short Answer Questions
1) What is electrolytic decomposition? Give one application.
2) How is exothermic reaction different from an endothermic reaction?

3) On adding a drop of Barium Chloride solution to an aqueous solution of Sodium Sulphite, white precipitate is obtained.
A) Write a balanced chemical equation of the reaction involved.
B) What other name can be given to this precipitation reaction?
C) On adding dilute Hydrochloric acid to the reaction mixture, white precipitate disappears. Why?​

Answer 1

Answer:

1. Calcium carbonate
2. Exothermic
3. Ans 4 CuSO4
4. Ans 5 - nitrogen
5. Ans 6

Answer 2

Answer:

1 -------------------- Decomposition takes place when limestone is heated strongly. This reaction helps in forming calcium oxide (CaO) and carbon dioxide (CO2).  Calcium oxide + carbon dioxide This process is known as decomposition.

2-------------------------- The reaction in which oxidation reduction taking place simultaneously are called as Redox reaction. In this examples copper oxide is reduced and acts as oxidizing agent and H2 is oxidized and acts as reducing agent. these are the reaction in which oxidation and reduction are occurs in a same compound.

3--------------------------- Silver is white in colour and when kept in sunlight silver chloride turns grey. ... This is so because the amount of energy of light decomposes AgCl to silver (Ag+) and chloride (Cl-) in the presence of sunlight . The silver chloride is actually black which is fully spread over white AgCl which looks grey.

4---------------------------Copper(II) sulfate, also known as copper sulphate, are the inorganic compounds with the chemical formula CuSO₄ₓ, where x can range from 0 to 5. The pentahydrate is the most common form. Older names for this compound include blue vitriol, bluestone, vitriol of copper, and Roman vitriol.

5-------------------------------- Nitrogen gas is the answer.it is because when the packed food is surrounded by an unreactive gas nitrogen ,there is no oxygenor air to cause its oxidation and make it rancid . but why ?? Nitrogen Gas is the gas which is used by manufacturers to fill the packets of chips

6---------------------------------------- A precipitation reaction is a type of chemical reaction in which two soluble salts in aqueous solution combine and one of the products is an insoluble salt called a precipitate. ... The liquid that remains when a precipitate forms is called the supernate.

7-----------------------The decomposition of vegetable into compost is an example of exothermic reaction. The decomposition of vegetable matter into useful compost is carried out by microbes. These reactions involve break down of bonds. The overall reaction is exothermic.

8---------------------When dilute sulphuric acid is poured on zinc granules, then zinc sulphate is formed along with the evolution of a gas. Zinc is more reactive than hydrogen, so displaced it from sulphuric acid.

9----------------------------------Lead nitrate on heating produces brown fumes of nitrogen dioxide.

10-------------------------Both reduction and oxidation go on at the same time which is a redox-reaction. The loss of hydrogen atoms and the gain of oxygen atoms is known as oxidation. The gain of hydrogen atoms and the loss of oxygen atoms is known as reduction.

11-------------------------Rancidification is the process of complete or incomplete oxidation or hydrolysis of fats and oils when exposed to air, light, or moisture or by bacterial action, resulting in unpleasant taste and odor.

12-----------------------  D. Sunlight on Silver Chloride

Short Answer Questions

1------------The decomposition reaction in which a substance is decomposed in to its constituents by use of electricity. Uses: 1) This reaction is used for the industrial preparation of aluminium, sodium, chlorine etc. 2) This reaction is used in electroplating.

2----------------- The difference between endothermic and exothermic reactions lies in the words themselves. "Thermic" refers to heat, just as in the word "thermometer." "Exo" means "outside" and "endo" means "inside." Thus, an endothermic reaction pulls heat into an object or area, while an exothermic reaction expels heat.

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