you wish to prepare an hc2h3o2 buffer with a ph of 5.44. if the pka of the acid is 4.74, what ratio of c2h3o2-/hc2h3o2 must you
1 answer:
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Answer:
V₂ = 16.5 L
Explanation:
To solve this problem we use <em>Avogadro's law, </em>which applies when temperature and pressure remain constant:
V₁/n₁ = V₂/n₂
In this case, V₁ is 22.0 L, n₁ is [mol CO + mol NO], V₂ is our unknown, and n₂ is [mol CO₂ + mol N₂].
- n₁ = mol CO + mol NO = 0.1900 + 0.1900 = 0.3800 mol
<em>We use the reaction to calculate n₂</em>:
2CO(g) + 2NO(g) → 2CO₂(g) + N₂(g)
- mol CO₂:
0.1900 mol CO * 0.1900 mol CO₂
- mol N₂:
0.1900 mol NO * 0.095 mol N₂
- n₂ = mol CO₂ + mol N₂ = 0.1900 + 0.095 = 0.2850 mol
Calculating V₂:
22.0 L / 0.3800 mol = V₂ / 0.2850 mol
V₂ = 16.5 L
Answer:
As the molecular mass of given amine is 163 g/mol (a odd number) it means that this compound contains a odd number of Nitrogen atoms. We will first apply Rule of Thirteen to get the molecular formula.
Rule of Thirteen:
First divide the parent peak value by 13 as,
= 163 ÷ 13
= 12.53
Now, multiply 13 by 12,
= 13 × 12 (here, 12 specifies number of carbon atoms)
= 156
Now subtract 156 from 163,
= 163 - 156
= 7
Add 7 into 12,
= 7 + 12
= 19 (hydrogen atoms)
So, the rough formula we have is,
C₁₂H₁₉
Now, add one Nitrogen atom to above formula and subtract one Carbon and 2 Hydrogen atoms as these numbers are equal to atomic mass of Nitrogen atom as,
C₁₂H₁₉ -------N--------> C₁₁H₁₇N
Also, as shown in ¹³C-NMR there is one peak around 180 ppm and the peak at 1661 cm⁻¹ in IR spectrum is characteristic to carbonyl group hence, we will add one oxygen atom to the chemical formula accordingly. i.e.
C₁₁H₁₇N -------O--------> C₁₀H₁₃NO
Molecular Formula: C₁₀H₁₃NO
Also,
In NMR the the four peaks around 120 ppm are assigned to a mono substituted benzene ring.
The absence of IR peak above 3200 cm⁻³ also confirms that the amine is tertiary in nature and there is no hydrogen attached to the nitrogen atom.
It can be observed that the peaks in upfield are duplicating. This can be due to the presence of rotamers of said compound.
The most plausible structure for given data is shown below, and the resonance structure along with rotamers are also shown.
