Answer:

Explanation:
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In this case, given the masses of copper, zinc and lead, it is possible to compute the moles via their atomic masses first:

Now, we compute the atomic percentages as shown below:

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For the answer to the question above asking w<span>hen an atom of n-14 is bombarded by an alpha particle, the single product is?
</span> <span>You're starting with 14/7 N, correct?
An alpha particle is two protons, two neutrons, which is 4/2, correct?
</span><span>So I</span> think the answer to your question is the third one which is <span>c. 18/9 f </span>
You have 0.50 mol of NH3 and 0.20 mol of NH4+ to start (NH4Cl dissolves completely), given the molarity and 1.0 L solution.
30.0 mL of 1.0 M HCl is 0.0300 mol of HCl. This will react with the NH3 to produced 0.030 mol of NH4+.
You now have 0.47 mol NH3 and 0.23 mol NH4+. Now use the Henderson-Hasselbach equation to calculate your pH. The equation says to use concentration of acid and base, but you can just use the moles of them because it doesn’t make a difference.
pH = pKa + log(base/acid)
pKa = 14 - pKb = 14 - 4.75 = 9.25
pH = 9.25 + log(0.47/0.23) = 9.56