I believe the correct answer from the choices listed above is the second option. Analgesics are the drugs that kill pain by blocking impulses at specific receptor sites of the brain and spinal cord. Analgesics<span> are drugs that alleviate pain without causing anesthesia. Hope this helps.</span>

We know that
, where
is density,
is mass, and
is volume.
Substitute in the values we know and solve:

0.99 x volume= 0.106 x 0.082 x 309
volume= 2.71 ml
Answer:
.224 M
Explanation:
To begin, we need to find the molar mass of Na2S
To find Molarity, we use the equation M=moles/Liters of solution
We are given grams, so we must divide by the molar mass of Na2S to find moles.
- 8.76g Na2S / 78.05g/mol Na2S= .112 moles
Now we use our Molarity equation:
- .112 moles Na2S / .500L of solution = .224 M
<h3><u>Answer</u>;</h3>
pH = 4.38
<h3><u>Explanation;</u></h3>
Consider that ;
[H3O+] = 10-pH mol/L
Therefore; the pH is the -log of the [hydronium ion].
pH = - log [H3O+]
Thus;
pH = - log (4.2 × 10^–5)
= 4.38