Ask me for chemistry help! (1 Viewer)

[s2 SEductive]

LMAO, Im retarded

No you're not! =]

 

[hscishard]

What is the conjugate base of all these:

• Hydrochloric acid
• Sulfuric acid
• Hydronium ion
• Hydrogensulfate ion
• Acetic acid
• Carbonic acid
• Ammonium ion
• Hydrogencarbonate ion
• Water
• Hydroxide ion

I Will rep those who answer it the quickest correctly =]

Are there several trick questions there? It looks like it for some reason

 

[s2 SEductive]

Are there several trick questions there? It looks like it for some reason

Nope.

 

[imZerroo]

how do i find pH and [H+] of diprotic or triprotic acids?
can someone please go over finding pH and [H+] for me please?
thnks

 

[hscishard]

Ok...then it must be because it's unfamiliar since some of them are conjugate bases themselves

 

[s2 SEductive]

how do i find pH and [H+] of diprotic or triprotic acids?
can someone please go over finding pH and [H+] for me please?
thnks

• pH = - log10[H+]
• [H+] = 10^-pH

Diprotic - 2 x [H+]
Tripotic - 3 x [H+]

 

[hscishard]

how do i find pH and [H+] of diprotic or triprotic acids?
can someone please go over finding pH and [H+] for me please?
thnks

Man I don't trust what I've learnt
Just multiply the concentration to the amount of hydronium ions that are produced.

However, aren't most diprotic and triprotic acids in a state of equilibrium? The pH will be greater than what you do from my working

 

[imZerroo]

• pH = - log10[H+]
• [H+] = 10^-pH

Diprotic - 2 x [H+]
Tripotic - 3 x [H+]

lets say [H+] of phosphoric acid is 2M
so pH will be -log[2x3] yup?
but if it ionises 10% (making this up btw), then pH= -log(2x3x10%)
am i right?

please tell me im right.

 

[jnney]

Just wait until i whip my book out.

 

[s2 SEductive]

lets say [H+] of phosphoric acid is 2M
so pH will be -log[2x3] yup?
but if it ionises 10% (making this up btw), then pH= -log(2x3x10%)
am i right?

please tell me im right.

-log[2x3] is correct
But I'm not really sure about the next one. I get your point as in tripotic ions ionise 3 times, so 10% will ionise 10% times.
Is this a proper question?

 

[imZerroo]

umm no.. i now get the diprotic, triprotic etc. bit
but idk about the degree of dissociation. lets say
acetic acid, ionises 1% in solution, and [H+]= 0.1M
so pH= -log(0.1x1%)
would that be right?

 

[hscishard]

No, if It ionises by 10% you add the hydronium ions to form one big concentration. I like that question, it's more realistic
Oh wait a minute, you are correct. I was thinking of H3PO4--> H+ +H2PO4-. As you keep going it ionises less,etc[not sure if phosphoric acid ionises like that

 

[Midnight_Lotus]

this is a pretty noob question, but in equilibrium if pressure is changed and there are equal moles on prod and reactancts what way does it shift or is their no shift

depends if they're all gases or not

Irrespective of if their is gases or not their will be no change if the amounts add up on both sides, however pressure is only relevant in gas equations anyways

 

[imZerroo]

wow you just confused me even more :L
so im right yes? :s

also Al2O3 is an example of an amphoteric substance? how do i prove it through an equation?

 

[s2 SEductive]

umm no.. i now get the diprotic, triprotic etc. bit
but idk about the degree of dissociation. lets say
acetic acid, ionises 1% in solution, and [H+]= 0.1M
so pH= -log(0.1x1%)
would that be right?

I guess soo.. well I think so because only 1% of 0.1M ionises in solution, and since pH is a measure of [H+] ions, it seems logical.

 

[hscishard]

wow you just confused me even more :L
so im right yes? :s

also Al2O3 is an example of an amphoteric substance? how do i prove it through an equation?

Ignore first part. I misinterpreted the question

 

[imZerroo]

k a lot clearer now.
i understood all this when we learnt it, now i have gone completely blank.
god bless stress.

 

[s2 SEductive]

wow you just confused me even more :L
so im right yes? :s

also Al2O3 is an example of an amphoteric substance? how do i prove it through an equation?

Al2O3 + 6 H+ --> 2 Al3+ + 3 H2O
Al2O3 + 3 H2O + 2 OH- --> 2 [Al(OH)4-]

 

[imZerroo]

sorry guys another question,
how do you know which salt is acidic, basic or neutral? i know it has something to do with cation/anion being the conjugate base/acid of another base/acid.
but idk how you know it.
thnks again and again.

 

[imZerroo]

Al2O3 + 6 H+ --> 2 Al3+ + 3 H2O
Al2O3 + 3 H2O + 2 OH- --> 2 [Al(OH)4-]

i can remember the equations, but how does it prove its amphoteric? looking by that do you look at Al's oxidation state?