1. What type of reaction is represented by the digestion of food in our body ? Oxidation
2 Name the various types of chemical reactions. Compound, durissement Contos
3. Why does the colour of copper sulphate solution change when an iron nail is kept immersed in it 2
4. Werte the balanced chemical equation for the following reaction :
Zinc + Silver nitrate
Zinc nitrate + Silver
s. Which term is used to indicate the development of unpleasant smell and taste in fat and oil containing foods
due to aerial oxidation (when they are kept exposed for a considerable time) ?
6. What is the general name of the chemicals which are added to fat and oil containing foods to prevent the
development of rancidity ?
7. State an important use of decomposition reactions,
8. What are anti-oxidants ? Why are they added to fat and oil containing foods?
9. Explain why, food products containing fats and oils (like potato chips) are packaged in nitrogen.
10. Give one example of a decomposition reaction which is carried out :
(a) with electricity
(b) by applying heat
11. What type of chemical reaction is used to extract metals from their naturally occurring compounds lilo
oxides or chlorides?
12. Name two anti-oxidants which are usually added to fat and oil containing foods to prevent rancidit
13. Write one equation each for the decomposition reactions where energy is supplied in the form of (a) he
(b) light, and (c) electricity,
14. In the refining of silver, the recovery of silver from silver nitrate solution involved displacement by copp
metal. Write down the chemical equation of the reaction involved.
15. What type of reactions are represented by the following equations ?
(1) CaCO3 + CaO + CO2
(ii) CaO + H2O -> Ca(OH)2
(iii) 2FeSO, Fe2O3 + SO2 + SO3
(ii) NH4Cl → NH3 + HCI
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Answers
Science (from the Latin word scientia, meaning "knowledge")[1] is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.[2][3][4]
The earliest roots of science can be traced to Ancient Egypt and Mesopotamia in around 3500 to 3000 BCE.[5][6] Their contributions to mathematics, astronomy, and medicine entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes.[5][6] After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages[7] but was preserved in the Muslim world during the Islamic Golden Age.[8] The recovery and assimilation of Greek works and Islamic inquiries into Western Europe from the 10th to 13th century revived "natural philosophy",[7][9] which was later transformed by the Scientific Revolution that began in the 16th century[10] as new ideas and discoveries departed from previous Greek conceptions and traditions.[11][12][13][14] The scientific method soon played a greater role in knowledge creation and it was not until the 19th century that many of the institutional and professional features of science began to take shape;[15][16][17] along with the changing of "natural philosophy" to "natural science."[18]
Modern science is typically divided into three major branches that consist of the natural sciences (e.g., biology, chemistry, and physics), which study nature in the broadest sense; the social sciences (e.g., economics, psychology, and sociology), which study individuals and societies; and the formal sciences (e.g., logic, mathematics, and theoretical computer science), which study abstract concepts. There is disagreement,[19][20][21] however, on whether the formal sciences actually constitute a science as they do not rely on empirical evidence.[22][20] Disciplines that use existing scientific knowledge for practical purposes, such as engineering and medicine, are described as applied sciences.[23][24][25][26]
Science is based on research, which is commonly conducted in academic and research institutions as well as in government agencies and companies. The practical impact of scientific research has led to the emergence of science policies that seek to influence the scientific enterprise by prioritizing the development of commercial products, armaments, health care, and environmental protection.