Volume<span> of matter </span>decreases<span> under </span>pressure<span> ... -under </span>pressure<span>, the </span>particles<span> in a </span>gas<span> are </span>forced closer together<span> ... </span>factors<span> affecting </span>gas pressure<span> ... -</span>if pressure<span> in a sealed container is </span>lower than<span> outside, </span>gas will<span> rush in ...</span>
We can use two equations for this problem.<span>
t1/2 = ln
2 / λ = 0.693 / λ
Where t1/2 is the half-life of the element and λ is
decay constant.
20 days = 0.693 / λ
λ = 0.693 / 20 days
(1)
Nt = Nο eΛ(-λt) (2)
Where Nt is atoms at t time, No is the initial amount of substance, λ is decay constant and t is the time
taken.
t = 40 days</span>
<span>No = 200 g
From (1) and (2),
Nt = 200 g eΛ(-(0.693 / 20 days) 40 days)
<span>Nt = 50.01 g</span></span><span>
</span>Hence, 50.01 grams of isotope will remain after 40 days.
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It may be unreliable because it might mess something up from the speed.
Chemical change
Hope this helps!
defined, a solid will always have a definite shape and volume because it doesn´t depend on its container shape