How has overpopulation changed the rule about recycling and use of resources
2 answers:
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Half-life is the time taken for the concentration of the substance to reduce by 50%. The original sample of strontium had a mass of 1.6 gms. Thus, option d is correct.
<h3>What is half-life?</h3>The half-life of any radioactive substance is the time period at which the concentration will get reduced to half the initial amount. The initial mass of Sr-90 is calculated as,
Given,
Quantity of the remaining substance N (t) = 0.40 gm
Initial radioactive substance quantity =?
Time duration (t) = 56 years
Half-life = 28 years
Substituting values above:
= 1.6 gm
Therefore, option d. the initial mass of Sr is 1.6 gm.
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Answer:1-methoxy-2,4-dinitrobenzene
Explanation:
The nitro groups are strongly electron withdrawing and promote nucleophilic substitution reactions where one of the original substituents is removed and replaced by a strong nucleophile such as the methoxy group. The mechanism of the reaction is attached below. The electron withdrawing nitrogroup assists the formation of the intermediate in the reaction as shown.
