pH (1 Viewer)

[Gavvvvvin]

What was the answer to that question where you had to determine the pH?

 

[stoydgen]

What was the answer to that question where you had to determine the pH?

I thought it was approx 4 or so...

 

[Gavvvvvin]

I somehow ended up with 8.3 =/

 

[sub]

which one was this?? can sum one write the q down or paraphrase...if its from the mid section?

 

[VVoody]

If you're talking about the HCl one, it was 3

 

[The Bograt]

I got 3, pretty confident too

 

[sub]

yeah i got 3 for that one if its HCl too...really easy...if it is then ill tell u how

 

[VVoody]

10mL of 0.01M HCl
90mL of distilled water added
Calculate new pH


How to:
Old conc: 0.01M
New conc: 0.001M (n=cv) <-- I think that's how you would do it, I did it by inspection

pH = - log[H+]
pH = - log [0.001]
pH = 3

 

[sub]

yeah it IS how u do it...i did it that way in case they give marks for working
i got it by inspection first tho

 

[VVoody]

lol, it's one mark. Only mark there is the answer

 

[L45er]

It was 3...

c1v1 = c2v2
c1 = 0.01mol/L
v1 = 0.01L
c2 = ?
v2 = 0.1L

Hence, (0.01x0.01)/0.1 = 0.001

-log[H+] = -log0.001 = 3

 

[sub]

watever..the ppl marking may wish to start a new trend...knoing how shit this paper was...id say anything could happen
but the answers the same either way

 

[tina_goes_doo]

I feel so stupid after reading VVoody's answer. I ended up with 3 but it was dodgy. Ended up to it in a nice round-a-bout way with multiplying by 9 and getting the log of that. I had no idea.

 

[scruffy012]

yeah ph=3 because it was a 10x dilution so it equaled 0.001 molL-1

-log 0.001 = 3

therefore pH=3

scruffy

 

[babygoose!]

woohoo! i ended up with 3 as well!

 

[Brad]

Yay I Got 3!!!