Radioactive material obeys 1st order decay kinetics,
For 1st order reaction, we have
k =
where, k = rate constant of reaction
Given: Initial conc. 100, Final conc. = 6.25, t = 18.9 hours
∴ k =
= 0.1467 hours^(-1)
Now, for 1st order reactions: half life =
= 4.723 hours.
The reactant is what you begin with.
The product is what you end up with (so the answer is B)
<span>That the mass is far lesser
and distributed mistakenly, as compared to what the orbits of stars declare it
should be. Stars orbit more rapidly than the mass would predict, particularly
out toward the galactic edge. This means that there is more mass than has been
measured, and that it is spread out in a huge cloud around the galaxy. This is
one of the reasons why scientists believe that dark matter exists.</span>
Answer:
It has to do with increasing the entropy of the universe.
Explanation:
The modern definition of entropy is that it is the extent to which a system is able to disperse its energy. Energy (such as heat!) likes to spread itself out, so that as many states as possible are occupied with the least amount of energy.
