Jump to content
Guests can now reply in ALL forum topics (No registration required!) ×
Guests can now reply in ALL forum topics (No registration required!)
In the Name of God بسم الله

Chemistry Help............


Recommended Posts

  • Advanced Member

Im on secondary 5 but i know this really well its only an acide like HCl + base (who finish with OH) ----> water + salt

Salt = Combinason of Acide and Base

Ex : U got KOH + HCl --> H2O + KCl

Its Easy hahah

lol i found it easy in Chem1 but im having trouble with it in chem 2 :/ my homework has four problems with these instructions:

Write net Bronsted equations and determine the equilibrium constants for the acid-base reactions that occur when aqueous solutions of the following are mixed.

one reaction of the four is acetic acid + ammonia and you have to figure out the net reaction equation which is

Acid(1) + Base(2) = Base(1) + Acid(2)

And you have to find K.... I dont understand how you can find K if you dont know the molarity of anything...

Link to post
Share on other sites
  • Advanced Member

lol organic chem :P my favorite subject..

well firstly this is the answer to your question...

CH3COOH + NH3NH+4 + CH3COO

Edited by alhashimi
Link to post
Share on other sites
  • Advanced Member

I made a huge post trying to explain how it works but I read it back and it made no sense at all.

Its an excellent explanation..

wallah i would try to help more bas i have an exam in less than 4 hours and one more lecture to memorize lol

Link to post
Share on other sites
  • Advanced Member

I made a huge post trying to explain how it works but I read it back and it made no sense at all.

Its an excellent explanation..

wallah i would try to help more bas i have an exam in less than 4 hours and one more lecture to memorize lol

Well I needed an explaination, too bad I didn't get a chance I read it before you erased it lol but jazakallah for trying and I hope you did well iA!

Link to post
Share on other sites
  • Advanced Member

Well I needed an explaination, too bad I didn't get a chance I read it before you erased it lol but jazakallah for trying and I hope you did well iA!

Apologies, however I can explain it now if you like? It really did make no sense, its why i deleted it lol

Al7amidulilah it went better than expected :)

Link to post
Share on other sites
  • Advanced Member

Apologies, however I can explain it now if you like? It really did make no sense, its why i deleted it lol

Al7amidulilah it went better than expected :)

Sure if you dont mind explaining :) I'll try to watch the video too after my classes iA and my exam is tomarrow :S illtemas e dua

And allhumdulilah (: that's great! Hope the rest of ur exams go well too iA

Don't you remember your high school chemistry?

This is fun stuff.

My high school chemistry was not really that great... I literally learned nothing from it... But my teacher had a policy that you were not allowed to get lower than a B on any assignment (if you did, you would make corrections and you would get full points back ) and you had the entire semester to turn in any and all assignments... Like you could turn in a project that was due in September in December... And he wouldnt take any points off for it being late. His only REQUEST was that we don't turn everything in on the last day of class so that he would have time to grade everything -.-'

He was a really nice guy tho, love him, but I learned nothing... Got great grades tho lol

Edited by Raafiki
Link to post
Share on other sites
  • Advanced Member

Bronsted equations (aka the conjugate stuff)..

A conjugate pair refers to acids and bases with common features. These common features are the equal loss/gain of protons between the pairs. Conjugate acids and conjugate bases are characterized as the acids and bases that loose or gain protons. In an acid-base reaction, and acid plus a base reacts to form a conjugate base plus a conjugate acid.

Acid + Base ---> Conjugate acid + Conjugate Base

The conjugate acid of a base is formed when the base gains a proton. For example the following equation:

NH3 + H2O ---> (NH4+) + (OH-)

We say that NH4+ is the conjugate acid to the base NH3, because NH3 gained a hydrogen ion to form NH4+, the conjugate acid. The conjugate base of an acid is formed when the acid donates a proton. In the equation, we say that OH- is the conjugate base to the acid H2O, because H2O donates a hydrogen ion to form OH-, the conjugate base.

Note: The stronger the acid or base, the weaker the conjugate. The weaker the acid or base, the stronger the conjugate.

In summary:

A conjugate acid of the base ---> (H+) + Base

A conjugate base of the acid---> Acid – (H+)

Further info if you want:

The acid and conjugate bases are conjugate pairs and the base and conjugate acids are conjugate pairs. When finding a conjugate acid or base, make sure you always look at the reactants. The reactants are the acids and bases, and the acid corresponds to the conjugate base on the product side of the equation. This goes for the base too; the base corresponds to the conjugate acid on the product side of the equation.

To identify the conjugate acid, look for the pair of compounds that are related. The acid-base reaction can be view in a before and after sense. The before is the reactant side of the equation, the after is the product side of the equation. The conjugate acid in the after side of an equation gains a hydrogen ion, so in the before side of the equation the compound that has one less hydrogen ion of the conjugate acid is the base. The conjugate base in the after side of the equation lost a hydrogen ion, so in the before side of the equation the compound that has one more hydrogen ion of the conjugate base is the acid.

Link to post
Share on other sites
  • Veteran Member

Hah! That's why I took the smart route and took Biology and Physics but left Chemistry right after Year 8! The decision was quite good, I see! :D

In fact, I even did an Istikhara once because in my GCSEs, after more than one year had passed, I wanted to go from commercial subjects to sciences. Biology came excellent, Chemistry, not so good. Thank God for guiding me! :D

I have to say, though, that even though all the people in my class, whether the clever ones or otherwise, find Chemistry the hardest, they usually get their best grades in Chemistry. Maybe that's got to do with the fact that they study more for it, as they find it hard, or maybe it's just because the examining body reduces grade thresholds because of poor performance, on average. End result: you'll get your best grades in Chemistry. :D

Link to post
Share on other sites
  • Advanced Member

Can some one also help me with this?... >.<

How many grams (to the nearest 0.01 g) of NH4Cl (Mm = 53.49 g/mol) must be added to 800. mL of 1.255-M solution of NH3 in order to prepare a pH = 9.10 buffer?

So I did pH=pKa +log (nb/na)

I looked up the pKa of NH4Cl to be 9.24

9.10=9.24+log(1.004/x)

x=1.38 mols

then i did 1.39mols(53.49g/mol)= 74.35 g

can some one check my work cuz I got 74.14 the first time i did the math, second time i got 74.08, and this time i got 74.35... and my hw said 74.14 and 74.08 were both wrong...

thanks

Link to post
Share on other sites
  • Advanced Member

I have a test on this in two days. In an effort to put it off, I come on to shiachat. Haven't logged into shiachat for like a year, and the first post I stumble upon is this one.

I'm guessing this isn't coincidence. I should start studying.

Link to post
Share on other sites

Join the conversation

You are posting as a guest. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...