Chemistry Lab C

Jacobi
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Re: Chemistry Lab C

Post by Jacobi » October 26th, 2018, 5:30 am

Dinoswarleafs wrote:
Jacobi wrote:
Volume of Object = 12.0 mL
Density = m/V = 8.7 g/mL = 8700 kg/m^3
Cool. Sorry about that :/

Give an element for n-type doping w/ Silicon
Arsenic?
Usually, the person who answered correctly asks the next question.

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Re: Chemistry Lab C

Post by Dinoswarleafs » October 26th, 2018, 7:26 am

Jacobi wrote: Usually, the person who answered correctly asks the next question.
Oops sorry. Havent done this before D:

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Re: Chemistry Lab C

Post by Jacobi » October 28th, 2018, 8:32 am

What is the pH of a mixture of molar ammonium with molar ammonia in aqueous sol'n? Ammonium has a of 9.20.

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Re: Chemistry Lab C

Post by Dinoswarleafs » October 28th, 2018, 7:45 pm

Jacobi wrote:What is the pH of a mixture of molar ammonium with molar ammonia in aqueous sol'n? Ammonium has a of 9.20.
[img]https://cdn.discordapp.com/attachments/294282012146139147/506294811070824468/20181028_213345.jpg[/img]
You made me realize on the UT inv yesterday I put the formula for ammonia as a base instead of ammonium dissociating. I was one off from placing. AAAAAAAAAAAAAAAAAAAAAAAAA

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Re: Chemistry Lab C

Post by Jacobi » October 29th, 2018, 6:53 am

Dinoswarleafs wrote:
Jacobi wrote:What is the pH of a mixture of molar ammonium with molar ammonia in aqueous sol'n? Ammonium has a of 9.20.
[img]https://cdn.discordapp.com/attachments/294282012146139147/506294811070824468/20181028_213345.jpg[/img]
You made me realize on the UT inv yesterday I put the formula for ammonia as a base instead of ammonium dissociating. I was one off from placing. AAAAAAAAAAAAAAAAAAAAAAAAA
The image didn't load for me.

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Re: Chemistry Lab C

Post by greenmilktea » November 5th, 2018, 5:17 pm

Jacobi wrote:What is the pH of a mixture of molar ammonium with molar ammonia in aqueous sol'n? Ammonium has a of 9.20.
6.2
A solution of a diprotic acid is standardized by titration with 0.20M NaOH. Calculate the molarity of the acidic solution if 30.24mL of the NaOH solution is required to completely neutralize 14.25mL of the acid solution.

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Re: Chemistry Lab C

Post by Jacobi » November 6th, 2018, 8:11 am

greenmilktea wrote:
Jacobi wrote:What is the pH of a mixture of molar ammonium with molar ammonia in aqueous sol'n? Ammonium has a of 9.20.
6.2
A solution of a diprotic acid is standardized by titration with 0.20M NaOH. Calculate the molarity of the acidic solution if 30.24mL of the NaOH solution is required to completely neutralize 14.25mL of the acid solution.
.212M
List two laws (i.e. Maxwell's Laws, Lorentz Law) involving magnetism and explain what they imply.

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Re: Chemistry Lab C

Post by whythelongface » December 18th, 2018, 11:08 pm

I guess I will bump with a question.
Which of the hydrohalic acids are the strongest? Justify your answer.
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Re: Chemistry Lab C

Post by primitivepolonium » January 20th, 2019, 10:03 pm

whythelongface wrote:I guess I will bump with a question.
Which of the hydrohalic acids are the strongest? Justify your answer.
No one's answered, so I'll go--HI.

Rule of strengths: ARIO (atom holding the charge, resonance, inductive effects, orbital), in that order. Usually you only get to A with mineral acids, since the proton is often attached to different Hs.

Since F, Cl, Br, I are all in the same family, electronegativity is not the main factor. What matters is bond dissociation energy. The H-I bond is easier to break, so deprotonation is easier.

Also--the strength of an acid depends on the stability of its conjugate base. I- is the most stable since it's the largest. They all have a -1 charge. I- is the largest, so the negative charge is distributed over a larger space and leads to greater stability.
My turn: HCl and HBr have the same acid strength in water, but they are clearly not the same strength. (They have different pKas). Why is this the case?
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Re: Chemistry Lab C

Post by jaah5211 » January 28th, 2019, 2:19 pm

primitive_polonium wrote:
whythelongface wrote:I guess I will bump with a question.
Which of the hydrohalic acids are the strongest? Justify your answer.
No one's answered, so I'll go--HI.

Rule of strengths: ARIO (atom holding the charge, resonance, inductive effects, orbital), in that order. Usually you only get to A with mineral acids, since the proton is often attached to different Hs.

Since F, Cl, Br, I are all in the same family, electronegativity is not the main factor. What matters is bond dissociation energy. The H-I bond is easier to break, so deprotonation is easier.

Also--the strength of an acid depends on the stability of its conjugate base. I- is the most stable since it's the largest. They all have a -1 charge. I- is the largest, so the negative charge is distributed over a larger space and leads to greater stability.
My turn: HCl and HBr have the same acid strength in water, but they are clearly not the same strength. (They have different pKas). Why is this the case?
This is due to the leveling effect. In water, all the acid's strengths are leveled to H3O+, and since both completely dissociates, their strengths are leveled to that of hydronium ion. To see the difference in strength, one can use different solvent such as ammonia
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