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Oliga [24]
3 years ago
7

19.The Alkali and Alkaline Earth metals belong to which columns, respectively?

Chemistry
1 answer:
Naily [24]3 years ago
4 0

Answer:

it HAS to be b or d I mostly think b

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4 years ago
The half-life of bismuth-210, 210bi, is 5 days. (a) if a sample has a mass of 184 mg, find the amount remaining after 15 days.
ASHA 777 [7]

Answer:- 23.0 mg

Solution:- Radioactive decay obeys first order kinetics and the first order kinetics equation is:

lnN=-kt+lnN_0

where, N_0 is the initial amount of radioactive substance and N is it's amount after time t. k is the decay constant.

From given information, Original amount, N_0 of the radioactive substance is 184 mg and we are asked to calculate the amount N after 15 days. It means, t = 15 days

Half life is given as 5 days. From the half life, we could calculate the decay constant k using the equation:

k=\frac{0.693}{t_1_/_2}

where, t_1_/_2 is the symbol for half life. let's plug in the value of half like to calculate k:

k=\frac{0.693}{5days}

k=0.1386day^-^1

Let's plug in the values in the first order kinetics equation and solve it for N:

lnN=-0.1386day^-^1(15days)+ln184mg

lnN=-2.079+5.215

lnN = 3.136

N=e^3^.^1^3^6

N = 23.0 mg

So, 23.0 mg of Bi-210 would be remaining after 15 days.

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4 years ago
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