If a substance can decay by two methods and half life for two methods is T1 and T2. Now if the substance decays by both methods then calculate effective half life.
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Identify the substance that is oxidised and substance that is reduced in the reaction. CuO(s) + H2(g) → Cu(s) + H2O(l)
It is a combination reaction.
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List two contraceptive methods and state two benefits of adopting these methods.
Two contraceptive methods are : (a) Creating mechanical barriers. (b) Using contraceptive pills. Two benefits of these methods are : (a) Protection from sexually transmitted diseases. (b) Sufficient gap between successive births.
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In one average-life, (a) half the active nuclei decay
(c) more than half the active nuclei decay
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Can you guess the similarities and differences in the life of Bakarwals people and the life of Changpas.
Both the Bakarwal’s and the Changpa’s live in the mountains of Jammu and Kashmir. Both of them move from one place to another, and keep on wandering. Both of them...
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A radioactive substance has a half-life of four months. Three-fourth of the substance would decay in
(c) As it is given that half life of given substance is 4 months. The amount of substance left after 4 months = 1/2 The amount of substance left after 8 months...
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A substance 'X' is used for testing co2. Identify substance 'X'
Answer: X=Ca(OH)2-Calcium Hydroxide Equation: CO2 + Ca(OH)2 →CaCO3 ( Calcium Carbonate)
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A solution of substance 'X' is used for white washing: (i) Name the substance'X' and write its formula.
(i) X→ Quick lime, fcrrmula - CaO (ii) CaO + H2O→ Ca(OH)2
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Bee-sting leaves a chemical substance that causes pain and irritation. Name the chemical substance.
Methanoic acid (HCOOH). Use of Baking soda can give relief on the stung area when applied on it.
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A beaker contains a solution of substance ‘A’. Precipitation of substance ‘A’ takes place when small amount of ‘A’ is added to the solution.
(ii), [Hint: If added substance dissolves, the solution is unsaturated. If it does not dissolve solution is saturated. If precipitation occurs solution is supersaturated.]
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A substance which reacts with oxygen giving heat is called a combustible substance. Which, one of the following is a combustible substance?
The Right option is : (d) wood
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