Part A.4 and Part B. In a hurry to complete the experiment, Anna withdrew two volumes of solution from Part A.2 before the preci
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Answer:
pH = 5.54
Explanation:
The pH of a buffer solution is given by the <em>Henderson-Hasselbach (H-H) equation</em>:
- pH = pKa + log
For acetic acid, pKa = 4.75.
We <u>calculate the original number of moles for acetic acid and acetate</u>, using the <em>given concentrations and volume</em>:
- CH₃COO⁻ ⇒ 0.377 M * 0.250 L = 0.0942 mol CH₃COO⁻
- CH₃COOH ⇒ 0.345 M * 0.250 L = 0.0862 mol CH₃COOH
The number of CH₃COO⁻ moles will increase with the added moles of KOH while the number of CH₃COOH moles will decrease by the same amount.
Now we use the H-H equation to <u>calculate the new pH</u>, by using the <em>new concentrations</em>:
- pH = 4.75 + log
= 5.54
Answer:
1.High pressure will cause the liquid to become solid :
<u>Describe both water and other substances</u>
2.High pressure will cause the solid to become liquid <u>:</u>
<u>It describe none : neither water nor other substances </u>
<u>This statement is :False for both water and other substances</u>
3.The solid is more dense than the liquid :
It describe other substance
<u>This statement is :False for water but true for other substances.</u>
4. In a phase diagram, the solid-liquid coexistence line has a negative slope.
It describes water:
<u>This statement is :True for water because solid ice is less dense than liquid water.</u>
<u>False for other substance, they have positive slope</u>
5.The molecules are closest in the liquid phase.
<u>This statement is :False for water and other substances </u>
6.The solid is less dense than the liquid:
It Describes water because ice is less dense than liquid water
7. In a phase diagram, the solid-liquid coexistence line has a positive slope.
It describe other substances
<u>This statement is :True for other substances but false for water</u>
8. The molecules are closest in the solid phase :
<u>Describes both water and other substances </u>
Explanation:
<u>Answers to statement 1 , 2,5 and 8</u>
<u>Answers to statement 1 , 2</u>
On increasing pressure and decreasing temperature , There occur<u> Phase transition</u> always for every substance :
From liquid to solid and gas to liquid
Hence,
In Both for water and other substance
<u>High pressure will cause the liquid to become solid.</u>
<u>Answers to statement 5,8 :</u>
2.The Particles of solid are closely packed hence there is maximum force of attraction between the particle of solid as compared to liquid and gases .
Hence , The molecules <u>of both water and other substance</u>s are closest in the solid phase
This also means that in liquid molecules are far apart .
Rest statement : 3, 4 ,6 ,7 are explained below(see attached image)
<u>The molecules are closest in the liquid phase is false statement and does not describe both water and other substance</u>
<u>Ice floats on water. For most other substances, however, the solid sinks in the liquid.</u>
This can be explained using the phase diagram of <u>water </u>:
The line DB is = the solid-liquid coexistence line
It has negative slope because , solid ice is less dense than liquid water . That is why ice floats on water because its density is less than water
Hence <u>Water is described truly by statement 4,6, </u>which are :
4. the solid-liquid coexistence line has a negative slope.
6.The solid is less dense than the liquid.
Rest 3,7 = describe by other substance
<u>other substance</u> : Solid is more dense than the liquid ,the solid-liquid coexistence line has a positive slope
