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Chemistry Unit 4 IAL (WCH04) - June 2014

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Reply 60

biochris

Original post by deathbychem

Hey one last thing, do you remember an infrared spectrum question?
what did you write for that?

there was a broad absorption at 3400-3300cm-1 => caused by O-H bond in alcohols
so it was propan-1-ol

Reply 61

Ayaa11

What is pH you guys got ? (the one we have to read from the curve ) , and is phenolphthalein okay as the indicator ?

Reply 62

Sophiathecreator

Original post by biochris

there was a broad absorption at 3400-3300cm-1 => caused by O-H bond in alcohols
so it was propan-1-ol

I'm pretty sure that's what i put :biggrin:

DDDDDD yay

Reply 63

Sophiathecreator

Original post by Ayaa11

What is pH you guys got ? (the one we have to read from the curve ) , and is phenolphthalein okay as the indicator ?

i used phenolphthalein too

Reply 64

biochris

Original post by Ayaa11

What is pH you guys got ? (the one we have to read from the curve ) , and is phenolphthalein okay as the indicator ?

pH=8.4.. I used thymol blue (base) (yellow to green) but I think phenlphthalein is ok, too

Reply 65

Ayaa11

Original post by Sophiathecreator

i used phenolphthalein too

Original post by biochris

pH=8.4.. I used thymol blue (base) (yellow to green) but I think phenlphthalein is ok, too

Thanks, hope it will be okay..oh but i think i just put pH as 8 or so, i was in a hurry

Reply 66

Sophiathecreator

Original post by Ayaa11

Thanks, hope it will be okay..oh but i think i just put pH as 8 or so, i was in a hurry

i was also in a hurry and put 8 haha

Reply 67

leafy9

What was everyone's Kp? Mine was 7.86.. (I can't remember what I wrote but that's something close to what I calculated.)

(edited 9 years ago)

Reply 68

biochris

For the Bronsted-Lowry acid defition I just wrote: proton donor... will they accept it?

Reply 69

Ayaa11

Original post by Sophiathecreator

i was also in a hurry and put 8 haha

Reply 70

biochris

Original post by leafy9

What was everyone's Kp? Mine was 7.86.. (I can't remember what I wrote but that's something close to what I calculated.)

mine was 56.6 with no units.. :/

Reply 71

Relaxedexams

Original post by leafy9

What was everyone's Kp? Mine was 7.86.. (I can't remember what I wrote but that's something close to what I calculated.)

My Kp was 56.6...

Reply 72

Relaxedexams

Original post by biochris

For the Bronsted-Lowry acid defition I just wrote: proton donor... will they accept it?

Yep. 1 mark.

Reply 73

Ayaa11

Original post by biochris

For the Bronsted-Lowry acid defition I just wrote: proton donor... will they accept it?

I wrote acid is a substance that donates protons

Reply 74

Relaxedexams

Original post by biochris

pH=8.4.. I used thymol blue (base) (yellow to green) but I think phenlphthalein is ok, too

That pH question was about half neutralized acid, so pH = pKa, and a line had to be drawn in the buffering region of the pH curve, to read the pH. I got 4. I'm not too sure though...

I too used the same indicator, but for colour change I put yellow to blue. :/

Reply 75

leafy9

two 56.6??? ahh. either my memory sucks or I did something wrong. :P

Reply 76

Ayaa11

Guys , i can't exactly remember my kp, i have a memory of 50 something too..idk for which one though. Did you get some 1.92 or something for part of that kp calculation ?