PLEASE HELP!! PLEASE??
Why do you think there might not be enough fresh water in the future?
1 answer:
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Answer:
Explanation:
A radioactive isotope is an isotope that undergoes nuclear decay, breaking apart into a smaller nucleus and emitting radiation during the process.
The half-life of an isotope is the amount of time it takes for a certain quantity of a radioactive isotope to halve.
For a radioactive isotope, the amount of substance left after a certain time t is:
(1)
where
is the mass of the substance at time t = 0
m(t) is the mass of the substance at time t
is the half-life of the isotope
In this problem, the isotope is uranium-235, which has a half-life of
We also know that the amount of uranium left in the rock sample is 6.25% of its original value, this means that
Substituting into (1) and solving for t, we can find how much time has passed:
Answer:
The feed ratio (liters 20% solution/liter 60% solution) is 3,08
Explanation:
In this problem you have a 20,0 wt% H₂SO₄ and a 60,0 wt% H₂SO₄ solutions.
100 kg of 20% solution are 100kg/1,139 kg/L = <em>87,8 L </em>
100kg×20wt% = 20 kg H₂SO₄. In moles:
20 kg H₂SO₄ × (1 kmol/98,08 kg) = 0,2039 kmol H₂SO₄≡ <em>203,9 mol</em>
The final molarity 4,00M comes from:
<em>(1)</em>
Where X moles and Y liters comes from 60,0 wt% H₂SO₄
100 L of 60,0 wt% H₂SO₄ are:
100L××
×
= <em>0,9164 kmolH₂SO₄ ≡ 916,4 moles</em>
That means:
X/Y = 916,4/100 = 9,164 <em>(2)</em>
Replacing (2) in (1):
Y(liters of 60,0 wt% H₂SO₄) = <em>28,52 L</em>
Thus, feed ratio (liters 20% solution/liter 60% solution):
87,8L/28,52L = <em>3,08</em>
I hope it helps!