Answer:
In engineering and science the common stand is two places.
For example if you get a calculation of 4.567 round up and give the result of 4.57
most metals conduct electricity and are very dull to the look. most metals are toxic if eaten and are hard.
aluminum is a type of metal they is softer than the opther and conducts eletricty like a boss.
nickel on the opther hand is also a metal but does not conduct a lot of electricy.
metals can be bent and others can break,
After 25 days, it remains radon 5.9x10^5 atoms.
Half-life is the time required for a quantity (in this example number of radioactive radon) to reduce to half its initial value.
N(Ra) = 5.7×10^7; initial number of radon atoms
t1/2(Ra) = 3.8 days; the half-life of the radon is 3.8 days
n = 25 days / 3.8 days
n = 6.58; number of half-lifes of radon
N1(Ra) = N(Ra) x (1/2)^n
N1(Ra) = 5.7×10^7 x (1/2)^6.58
N1(Ra) = 5.9x10^5; number of radon atoms after 25 days
The half-life is independent of initial concentration (size of the sample).
More about half-life: brainly.com/question/1160651
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