Answer:

Explanation:
Hello.
In this case, taking into account that HCl has one molecule of hydrogen per mole of compound which weights 36.45 g/mol, we compute the number of molecules of hydrogen in hydrochloric acid by considering the given mass and the Avogadro's number:

Now, from the 180 g of water, we see two hydrogen molecules per molecule of water, thus, by also using the Avogadro's number we compute the molecules of hydrogen in water:

Thus, the total number of molecules turns out:

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Answer:
1249.88 mol.
Explanation:
∵ no. of moles of Fe = mass of Fe/atomic weight of Fe.
<em>∴ no. of moles of Fe </em>= (6.98 x 10⁴ g)/(55.845 g/mol) = <em>1249.88 mol.</em>
Answer:
212.5 mL
both the original and the diluted solution have 0.765 moles of KCl
Explanation:
c1V1 = c2V2
V2 = c1V1/c2 = (1.8 M×425 mL)/1.2 M = 637.5 mL
(637.5 - 425) mL = 212.5 mL
n = (1.8 mol/L)(0.425 L) = 0.765 moles of KCl
since it's a dilution, the diluted solution has the same number of moles as the original solution, 0.765 moles of KCl
I believe the correct answer from the choices listed above is option A. The topic that the teacher is talking about would be distillation of a mixture. Gasoline is processed by distillation. Hope this answers the question. Have a nice day.