Describe the structure of a complex molecule such as plastic at the molecular level.
1 answer:
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Answer:
1. C = 0.73 M.
2. pH = 0.14
Explanation:
The reaction is the following:
HCl + NH₃ ⇄ NH₄⁺Cl⁻
From the titration, we can find the number of moles of HCl that were neutralized by the ammonia.
Where "a" is for acid and "b" is for base.
The number of moles is:
Where "C" is for concentration and "V" for volume.
Hence the initial concentration of the acid is 0.73 M.
The original pH of the acid is given by:
Therefore, the original pH of the acid is 0.14.
I hope it helps you!
Answer:
percent yield = 40.6 %
Explanation:
The question asks to determine the percent yield, which can be defined as:
percent yield =
where the actual yield is how much product was obtained, in this case 12.5 g of CCl₂F₂, and the theoretical yield is how much product could be obtained with the given reactants theoretically.
So we know already the actual yield, we need to <em>calculate the theoretical yield.</em>
First we need to <em>write the reaction chemical equation</em>:
CCl₄ + HF → CCl₂F₂ + HCl
and <em>balance the equation</em>:
CCl₄ + 2 HF → CCl₂F₂ + 2 HCl
In the equation we can see that <em>for every mol of CCl₄ we should get 1 mol of CCl₂F₂</em> (molar ratio 1:1). So if we <u>calculate the moles of CCl₄</u> in the given 39.2 g of CCl₄ we could know how many moles of CCl₂F₂ (assuming HF is in excess).
- Moles of CCl₄ = mass CCl₄ / molar mass CCl₄
- Molar Mass CCl₄ = 12.011 + 4 * 35.45 = 153.811 g/mol
- Moles of CCl₄ = 39.2 g / 153.811 g/mol = 0.2549 moles
From the molar ratio we know:
Moles of CCl₂F₂ = moles of CCl₄ = 0.2549 moles
Now we need to <u>convert these moles into grams</u> to get the theoretical yield of CCl₂F₂ in grams:
- mass CCl₂F₂ = moles CCl₂F₂ * molar mass CCl₂F₂
- Molar Mass CCl₂F₂ = 12.011 + 2 * 35.45 + 2 * 18.998 = 120.907 g/mol
- Mass CCl₂F₂ = 0.2549 moles * 120.907 g/mol = 30.81 g
- Theoretical yield CCl₂F₂ = 30.81 g
Percent yield = (12.5 g / 30.81 g) * 100 = 40.6 %