Case Study Questions Class 10 Science Chapter 1 Chemical Reactions and Equations
CBSE Class 10 Case Study Questions Science Chemical Reactions and Equations. Important Case Study Questions for Class 10 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Chemical Reactions and Equations.
At Case Study Questions there will given a Paragraph. In where some Important Questions will made on that respective Case Based Study. There will various types of marks will given 1 marks, 2 marks, 3 marks, 4 marks.
CBSE Case Study Questions Class 10 Science Chemical Reactions and Equations
Case Study 1
A solution of slaked lime produced by the reaction is used for white washing walls. Calcium hydroxide reacts slowly with the carbon dioxide in air to form a thin layer of calcium carbonate on the walls. Calcium carbonate is formed after two to three days of white washing and gives a shiny finish to the walls. It is interesting to note that the chemical formula for marble is also CaCO3.
On the basis of above paragraph answer the following questions:
1.) Give the reaction for the formation of calcium carbonate with physical states.
Ca(OH)2(s) + CO2(g) → CaCO3(s)↓ + H2O(l)
2.) Write the formulas of slaked lime, quick lime.
Slaked lime: Calcium hydroxide is called as slaked lime with a formula of : Ca(OH)2 ,whereas calcium oxide is called as quick lime with a formula of : Ca0.
3.) Explain why calcium carbonate is used for white washing and not any other substance.
Calcium carbonate is used for whitewashing as it produces a shiny film whilst the production of carbon dioxide and act as hard coating for the walls.
4.) Explain the importance of writing the physical states in a chemical equation.
In any chemical reaction, physical states mention the nature of the reaction and their practical aspects which are necessary for lab uses.Physical states also explains whether reaction is exothermic or endothermic.
5.) Write any one application of calcium carbonate other than white washing.
Calcium carbonate is also used in the production of antacids and can also be used to increase the levels of calcium in body.
CASE STUDY : 2
You must have observed that iron articles are shiny when new, but get coated with a reddish brown powder when left for some time. This process is commonly known as rusting of iron. Some other metals also get tarnished in this manner. Have you noticed the colour of the coating formed on copper and silver? When a metal is attacked by substances around it such as moisture, acids, etc., it is said to corrode and this process is called corrosion. The black coating on silver and the green coating on copper are other examples of corrosion.
1.) Explain one benefit of corrosion.
Ans. Corrosion occurring in red blood cells of iron makes the colour of cells red which is highly useful in transportation of oxygen.
2.) Write the formula of corrosion of iron.
Ans. The general formula of corrosion of iron is Fe2 O3.
3.) If corrosion occurs in the case of iron articles, why is the iron pillar at Qutub Minar not effected?
Ans. The iron pillar at Qutub Minar is an ancient piece of metal knowledge in which the metal is very very pure( wrought iron) with low sulphur content and high phosphorus making it resistive to the outer environment.
4.) Write any two ways to prevent rusting.
Ans. The two ways to prevent rusting are:
A) Galvanization.
B) Painting of iron articles.
5.) What doe you mean by galvanization?
Ans. Galvanization is the process of applying a protective layer of Zn coating on materials which are prone to rust making it resistive and long lasting.
CASE STUDY : 3
When fats and oils are oxidized, they become rancid and their smell and taste change. Usually substances which prevent oxidation (antioxidants) are added to foods containing fats and oil. Keeping food in air tight containers helps to slow down oxidation.
1.) What do you mean by the word RANCIDITY?
Ans. The spoiling of food due to oxidation of fats and oils present in the food material
2.) Write any three methods to prevent rancidity.
Ans. Three methods to prevent rancidity of food includes:
A) Salting
B) Adding preservatives like vinegar
C) Storing in air tight containers.
3.) What is the meaning of antioxidants. Give an example.
Ans. The type of substances which can prevent the oxidation process of certain food materials are called as antioxidants. Some natural antioxidants are vitamin c, selenium etc.
4.) Which gas is filled in the chips packets to keep them crunchy?
Ans. The gas filled in chips packets is nitrogen gas which can keep the chips crunchy.
5.) Write any traditional method used by our ancestors to prevent rancidity.
Ans. There are a few methods used by our ancestors to prevent rancidity:
A) Salting
B) Sugaring
C) Pickling
CASE STUDY : 4
We have seen that the decomposition reactions require energy either in the form of heat, light or electricity for breaking down the reactants. Reactions in which energy is absorbed are known as endothermic reactions.
1.) Write the definition of exothermic reaction.
Ans. Reactions in which heat is evolved during the process are called as exothermic reactions, such as mixing of calcium oxide with water.
2.) What do you mean endothermic reactions?
Ans. Reactions in which heat is trapped or absorbed are called as endothermic reactions, such as glucose mixed with water.
3.) Write a reaction which falls under endothermic reaction.
Ans. Melting of ice, evaporation are considered under endothermic reactions. A chemical equation for these types of reaction is:
N2 + O2 + heat → 2 NO
4.) What is decomposition reaction?
Ans. Reactions in which a substance or reactant fragments to give one or many products.
5.) Explain photolysis.
Ans. Reactions in which reactant id decomposed with the help os sunlight are called as photolytic decomposition.
Ex: 2AgCl + sunlight → 2Ag + Cl2
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