Chemistry Lab C

Jacobi
Exalted Member
Exalted Member
Posts: 137
Joined: September 4th, 2018, 7:47 am
Has thanked: 0
Been thanked: 0

Re: Chemistry Lab C

Post by Jacobi »

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.
Dinoswarleafs
Member
Member
Posts: 20
Joined: November 10th, 2017, 8:37 pm
Has thanked: 0
Been thanked: 0

Re: Chemistry Lab C

Post by Dinoswarleafs »

Jacobi wrote: Usually, the person who answered correctly asks the next question.
Oops sorry. Havent done this before D:
Jacobi
Exalted Member
Exalted Member
Posts: 137
Joined: September 4th, 2018, 7:47 am
Has thanked: 0
Been thanked: 0

Re: Chemistry Lab C

Post by Jacobi »

What is the pH of a mixture of molar ammonium with molar ammonia in aqueous sol'n? Ammonium has a of 9.20.
Dinoswarleafs
Member
Member
Posts: 20
Joined: November 10th, 2017, 8:37 pm
Has thanked: 0
Been thanked: 0

Re: Chemistry Lab C

Post by Dinoswarleafs »

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
Jacobi
Exalted Member
Exalted Member
Posts: 137
Joined: September 4th, 2018, 7:47 am
Has thanked: 0
Been thanked: 0

Re: Chemistry Lab C

Post by Jacobi »

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.
User avatar
greenmilktea
Member
Member
Posts: 8
Joined: November 5th, 2018, 4:33 pm
Division: C
State: NJ
Has thanked: 0
Been thanked: 0

Re: Chemistry Lab C

Post by greenmilktea »

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.
Jacobi
Exalted Member
Exalted Member
Posts: 137
Joined: September 4th, 2018, 7:47 am
Has thanked: 0
Been thanked: 0

Re: Chemistry Lab C

Post by Jacobi »

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.
User avatar
whythelongface
Exalted Member
Exalted Member
Posts: 326
Joined: March 12th, 2017, 7:42 pm
Division: Grad
State: NJ
Has thanked: 1 time
Been thanked: 0

Re: Chemistry Lab C

Post by whythelongface »

I guess I will bump with a question.
Which of the hydrohalic acids are the strongest? Justify your answer.
WEST WINDSOR-PLAINSBORO HIGH SCHOOL SOUTH '18
EMORY UNIVERSITY '22
SONT 2017 5th Place Medalist [Microbe Mission]

"One little Sciolyer left all alone,
He went out and hanged himself and then there were none."

Congratulations to WW-P South/Grover for winning 2nd/1st place at NJ States!
primitivepolonium
Member
Member
Posts: 53
Joined: August 3rd, 2013, 9:00 am
Division: Grad
State: CA
Has thanked: 0
Been thanked: 0

Re: Chemistry Lab C

Post by primitivepolonium »

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?
Div D! I really like chem, oceanography, and nail polish--not in that order.

Troy HS, co2016.

Feel free to PM me about SciOly or college or whatever! I really enjoy making online friends.
jaah5211
Member
Member
Posts: 63
Joined: October 22nd, 2017, 7:42 pm
Division: Grad
State: FL
Pronouns: He/Him/His
Has thanked: 0
Been thanked: 9 times

Re: Chemistry Lab C

Post by jaah5211 »

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
Post Reply

Return to “2019 Question Marathons”

Who is online

Users browsing this forum: No registered users and 3 guests