1. What is a redox reaction?
2. What is corrosion? Explain its advantage and disadvantage.
3. What is rancidity? How can we reduce the problem of rancidity?
4. How is corrosion different from rusting?
5. What is meant by endothermic and exothermic reactions? Give suitable example for each.
6. Define different types of chemical reaction and give examples for each.
7. Why is photosynthesis considered as an endothermic reaction?
8. In electrolysis of water, why is the volume of gas collected over one electrode double that of the other electrode?
9. What happens when water is added to solid calcium oxide taken in a container? Write a chemical formula for the same.
10. Give one use of quick lime.
11. Give three types of decomposition reaction.
12. Name the compound used for testing CO2 gas.
Answers
Answer:
it happens when water is added to solid calcium oxide taken in a container? Write a chemicaula for the same.ive one use of quick li three types of decomposition reaction.me the compound used for testing CO2 gas.
Answer:
1. Redox is a type of chemical reaction in which the oxidation states of atoms are changed. Redox reactions are characterized by the actual or formal transfer of electrons between chemical species, most often with one species undergoing oxidation while another species undergoes reduction.
2. The natural process that causes the transformation of pure metals to undesirable substances when they react with substances like water or air is called corrosion.
Advantages
Following are the advantages of corrosion:
i) Layer of protection: A layer of oxide is formed on the surface that is corrosion protects the inner metal from corrosion
ii) Sacrificial anodes such as zinc is used as a preventive measure to stop corrosion of other metals
iii) Galvanic corrosion: This kind of corrosion occurs when two different types of metals are in electrical contact in an electrolyte where the more active metal tends to corrode.
Disadvantages
Following are the disadvantages of corrosion:
i)Lose of metal from the surface
ii) The physical appearance of a metal object changes
iii)The chemical properties of metal varies
iv)Lose of the efficiency of metallic machines
v) The life span of metallic objects decreases
3. The condition produced by aerial oxidation of fats and oils in foods marked by unpleasant smell and taste is called rancidity. ... Rancidity can be prevented by adding anti -oxidants to foods containing fats and oils. ... Rancidity can be prevented by packaging fats and oil containing foods in nitrogen gas.
4. The main difference though between corrosion and rust is that corrosion occurs as a result of the chemical influence and it affects a lot of materials whereas rusting is only accelerated by certain chemicals and usually affects iron substances.
5. reaction in which heat energy is liberated by the reactants is called exothermic reaction. eg: Carbon + Oxygen gives Carbon Dioxide + Q. reaction in which heat energy is absorbed by the reactants is called endothermic reaction. eg: Nitrogen + Oxygen gives 2 nitrous oxide (2NO) - Q.
6. The five basic types of chemical reactions are combination, decomposition, single-replacement, double-replacement, and combustion. Analyzing the reactants and products of a given reaction will allow you to place it into one of these categories. Some reactions will fit into more than one category.
7. Photosynthesis is an endothermic reaction because sunlight is being absorbed during the reaction and the definition suggests that in a reaction if heat is being absorbed it is termed as an endothermic reaction.
8. Water composition is 2atoms of H and 1atom of O . Therefore H is double than O . The two electrodes collect H and O separately . We know that hydrogen composition in water is double than oxygen , so we find volume of gas collected in one electrode is double than volume of gas collected in another electrade.
9. When calcium oxide is added to water it forms calciun hydroxide Called slaked lime. CaO +H2O →Ca(OH)2 The reaction between water and CaO is an exothermic reaction. Heat is released during exothermic reaction ,rise in temperature is observed.
10. Quicklime has a wide range of uses, including in the production of iron and steel, paper and pulp production, treatment of water and flue gases and in the mining industry. For the iron and steel industry, we also supply different fractions of both reactive shaft furnace-burnt and hard-burnt rotary kiln lime.
11. Decomposition reactions can be classified into three types: Thermal decomposition reaction. Electrolytic decomposition reaction. Photo decomposition reaction.
12. Carbon dioxide
Limewater is a solution of calcium hydroxide. If carbon dioxide is bubbled through limewater, the limewater turns milky or cloudy white.