Answer:
- <u>The container must be built of lead, and it should be kept in a concrete vault.</u>
Explanation:
The goal is to contain the <em>gamma rays</em> to<em> reduce</em> the <em>exposure </em>to their harmful <em>radiation</em>.
The gamma rays are the most energetic electromagnetic radiation: they have the smallest wavelength, the largest frequency, and the largest energy from all the electromagnetic radiations.
Due to that, only very dense substances like lead and concrete can stop the gamma rays. In the case of concrete, large blocks with thick walls are required.
Thus, in a lab the best container for a sample of uranium - 238 that is decaying, emitting gamma rays, must be built of lead, and enclosed in a conrete vault.
The answer is A.18 let me know if you want an explanation
<h3>
Answer:</h3>
A. 1.4 V
<h3>
Explanation:</h3>
We are given the half reactions;
Ni²⁺(aq) + 2e → Ni(s)
Al(s) → Al³⁺(aq) + 3e
We are required to determine the cell potential of an electrochemical cell with the above half-reactions.
E°cell = E(red) - E(ox)
From the above reaction;
Ni²⁺ underwent reduction(gain of electrons) to form Ni
Al on the other hand underwent oxidation (loss of electrons) to form Al³⁺
The E.m.f of Ni/Ni²⁺ is -0.25 V and that of Al/Al³⁺ is -1.66 V
Therefore;
E°cell = -0.25 V - (-1.66 V)
= -0.250V + 1.66 V
= + 1.41 V
= + 1.4 V
Therefore, the cell potential will be +1.4 V
