Help needed - chemistry

[monolog]

9 minutes ago, studiot said:

And it has achieved its objective.

So did my false indignation. 

 

11 minutes ago, studiot said:

A weak acid or base is one which is only partially dissociated into ions in solution.

I definitely lack basic knowledge. How do I know if a compound partially or fully dissociates into ions in a solution? What in its formulae gives me that information?

[hypervalent_iodine]

7 minutes ago, monolog said:

So did my false indignation. 

 

I definitely lack basic knowledge. How do I know if a compound partially or fully dissociates into ions in a solution? What in its formulae gives me that information?

 

There are not a lot of hard and fast rules with figuring it out. There are some things you should know. Organic acids tend to be weak. Carboxylic acids, for example. Ammonia is a good example of a weak base. Strong acids you encounter most are things like HCl, and H2SO4. Strong bases you encounter at this level are frequently hydroxides, like NaOH. Generally though, whether or not you are dealing with a weak acid or base should be implicit in the question. If they give you a Ka or Kb, it’s fair to assume you’re dealing with a weak acid or base. Similarly, if they give a dissociation reaction using equilibrium arrows, it’s probably a weak acid or base. You can also tell by looking at the equivalence points on titration curves, if given. 

[monolog]

18 minutes ago, hypervalent_iodine said:

particularly since once you add the two volumes together the concentrations change

I'll try to figure that out.

1 minute ago, hypervalent_iodine said:

There are not a lot of hard and fast rules with figuring it out. There are some things you should know. Organic acids tend to be weak. Carboxylic acids, for example. Ammonia is a good example of a weak base. Strong acids you encounter most are things like HCl, and H2SO4. Strong bases you encounter at this level are frequently hydroxides, like NaOH. Generally though, whether or not you are dealing with a weak acid or base should be implicit in the question. If they give you a Ka or Kb, it’s fair to assume you’re dealing with a weak acid or base. You can also tell by looking at the equivalence points on titration curves, if given.

These are good guidelines, thank you. I'll google more on it, but for now I'll be going back to the assignment. Have a good day.

27 minutes ago, studiot said:

Now can you attempt Hypervalent Iodine's questions?

 

I will try. Have a good day.

[studiot]

I think you should be aiming for the following values

[CH₃COOH] = 0.131

[CH₃COO^-] = 0.023

 

Can you show the calculations to achieve this, following Hypervalent Iodine's suggestions?

[monolog]

Not yet, I can't. But I will.

Or maybe I won't. I don't know how to get to those values. I don't even know which is [A^-] and which is [HA]. From the time management point of view it's not fruitful to waste time trying to do some juggling patchwork just to earn another point in this assignment. It's actually ridiculous to waste 2 days on something I could learn in 20 minutes with a private tutor. It's definitely better to move on to geology and make sure I excel in that one as I can actually learn the subject on my own. 

Edited January 4, 2019 by monolog

[hypervalent_iodine]

4 hours ago, monolog said:

Not yet, I can't. But I will.

Or maybe I won't. I don't know how to get to those values. I don't even know which is [A^-] and which is [HA]. From the time management point of view it's not fruitful to waste time trying to do some juggling patchwork just to earn another point in this assignment. It's actually ridiculous to waste 2 days on something I could learn in 20 minutes with a private tutor. It's definitely better to move on to geology and make sure I excel in that one as I can actually learn the subject on my own. 

 

As someone who has tutored this subject for 9 years, I can tell you that you aren’t going to get anything useful out of learning something in 20 minutes if you don’t back it up with your own study. Time and time again, the students I saw who continued to do poorly were always the ones who treated sessions as their primary form of study. 

We are simply trying to figure out what you know and what you don’t, and prompt you in the right direction. If you truly cannot figure out what the acid and conjugate base is in your question, then you are simply not equipped to do this assignment, and you need to (as I mentioned previously) go away and spend time learning and practicing questions related to the module. You are going to spend several hours / days studying this stuff if you want to be able to understand it.

[monolog]

17 minutes ago, hypervalent_iodine said:

If you truly cannot figure out what the acid and conjugate base

When I asked I was told the brackets are there to indicate whatever. Well, I'm not gonna waste my time here while you circle jerk simple questions between yourselves. Wanna help people? Straight forward do it. Wanna use this forum to treat strangers the way you can't treat your students? I don't need that shit. Tutoring for 9 years? That sure explains it.

[hypervalent_iodine]

You are missing so much knowledge required by this question that the only way to really help you here is to give you the answer. That doesn’t help you learn anything, and I personally don’t need to prove that I can complete a first year chemistry assignment. As I said before, the help you need for this is too comprehensive to be reasonably addressed in a forum such as this.  You’re just missing too much of the fundamentals. I recommend this site if you’re interested in studying it some more: https://www.chemguide.co.uk/physical/acideqiamenu.html#top

You’re welcome to come back if you have questions. If not, I wish you the best. 

1 hour ago, monolog said:

When I asked I was told the brackets are there to indicate whatever.

 

I told you what they represented on the previous page. HA is the general form of an acid (in-tact), and A- is the deprotonated form of the same acid, aka the conjugate base. I was asking you what HA and A- correspond to in your specific question. 

[studiot]

12 hours ago, monolog said:

When I asked I was told the brackets are there to indicate whatever. Well, I'm not gonna waste my time here while you circle jerk simple questions between yourselves. Wanna help people? Straight forward do it. Wanna use this forum to treat strangers the way you can't treat your students? I don't need that shit. Tutoring for 9 years? That sure explains it.

Being a smart ass may have served you well in the army, but doesn't wash in Science.

I am not going provide the means for someone whose stated aim is to gain marks he doesn't deserve.

You may not have noticed but there are quite a few first class Chemists here and most of them have avoided this thread.

Can you think why?

I will and have provided a lot of support for someone who wants to learn the why and wherefores of the subject and is prepared to at least think about the questions and make a reasonable attempt.

We have in this forum ( and others) laid out the complete calculation from start to finish, though usually not all in one go, for those who cooperate and actually learn and benefit from this.

Go well in you end of term/year exams.

The Open University is no picnic, in fact it is a very tough route.
 

Edited January 5, 2019 by studiot