Chemistry practical 34 oct/nov important

[soccerprinc3]

Ok..nvm..come to think of it, it is s^-1

 

[shikha95]

Yousuf has a point there...the units should be s^-1*1000....because usually the rate is 1/time so you get s^-1*1 (which is the same as s^-1) but in this case it was 1000/time...can't believe i didn't think of that!! >.<

It will not be s^-1. It would be s^-1*10^3..... This question came in 2003... check there.

Come on! 1000 doesn't have a unit! But time has a unit! It was 1000/time, so it was (no-unit/s) so it was s^-1
It couldn't have been s^-1000

 

[soccerprinc3]

wasnt it an ester?

The compound formed that gave off a sweet smell was an ester but FB8 contained a carboxylic compound

 

[rizwaan]

The compound formed that gave off a sweet smell was an ester but FB8 contained a carboxylic compound

yes you got it right fb8 is a carboxylic acid.

 

[Nishii]

The compound formed that gave off a sweet smell was an ester but FB8 contained a carboxylic compound

i didnt do the paper, i just heard about it

 

[Yousuf Ykr]

Come on! 1000 doesn't have a unit! But time has a unit! It was 1000/time, so it was (no-unit/s) so it was s^-1
It couldn't have been s^-1000

Well, multiply or diving by a constant sometimes change the unit. For example, you can change the unit 1cm by multiplying with 10 and this would turn into 10mm. In our case, we dont know what unit we are getting. thats why we have to write the full form i.e s^-1*1000. If anyone doubts me or have confusion then please look at the question no#1 in M/J 2003 before assuming something.

 

[Yousuf Ykr]

it turned blue litmus paper red.

It was also oxidised by potassium di chromate and had a sweet smell. So, it cannot be carbo xylic acid as it is not possible to oxidise Carboxylic acid (unless it is KMno3). So would it be SO2?

 

[soccerprinc3]

I

It was also oxidised by potassium di chromate and had a sweet smell. So, it cannot be carbo xylic acid as it is not possible to oxidise Carboxylic acid (unless it is KMno3). So would it be SO2?

It was sodium acetate

 

[Z.S.M]

Well, multiply or diving by a constant sometimes change the unit. For example, you can change the unit 1cm by multiplying with 10 and this would turn into 10mm. In our case, we dont know what unit we are getting. thats why we have to write the full form i.e s^-1*1000. If anyone doubts me or have confusion then please look at the question no#1 in M/J 2003 before assuming something.

Just saw the paper you're talking about. Even so, what will be the units of the '10^3' that's written? And if you see part b of the same question, the units of rate in the marking scheme are s^-1.
because rate is inversely proprtional to time. AND CONSTANTS HAVE NOT UNITS.

 

[Z.S.M]

wasnt it an ester?

the gas that was liberated wasn't an ester. the white solid that formed, was. the gas was acidic.

 

[Z.S.M]

I
It was sodium acetate

oh blimey! really soccerprinc3?

 

[Z.S.M]

It was also oxidised by potassium di chromate and had a sweet smell. So, it cannot be carbo xylic acid as it is not possible to oxidise Carboxylic acid (unless it is KMno3). So would it be SO2?

there wasn't any dichromate provided as it wasn't mentioned in the reagent checklist. so we couldn't know.

 

[ICTloverz]

Guys.. their was a question in which we had to measure the conc of Hydrogen Peroxide.. we were given the volume as 50 and 130 along with the conc. in the 1st question after graphs.. anyone did it..

 

[Z.S.M]

Guys.. their was a question in which we had to measure the conc of Hydrogen Peroxide.. we were given the volume as 50 and 130 along with the conc. in the 1st question after graphs.. anyone did it..

(vol. in experiment/130) x 0.23
for both experiments
What did you do?

 

[ICTloverz]

I did it same.. they gave for the first part as 50 and the next was 20 or 10.. and I did it this was.. 50/130 x .23 .. I am shocked.. that means from the full schoool I am correct.. lol. Thanks Zahra.. are u on FB

 

[ICTloverz]

and FB8 was ester right??

 

[Z.S.M]

I did it same.. they gave for the first part as 50 and the next was 20 or 10.. and I did it this was.. 50/130 x .23 .. I am shocked.. that means from the full schoool I am correct.. lol. Thanks Zahra.. are u on FB

i am. but i don't socialise with everyone there. it's just for my FnF

 

[Z.S.M]

and FB8 was ester right??

what we made from FB8 was an ester. FB8 was a compound of a carboxylic acid, sodium acetate to be exact.

 

[Yousuf Ykr]

In the mar

Just saw the paper you're talking about. Even so, what will be the units of the '10^3' that's written? And if you see part b of the same question, the units of rate in the marking scheme are s^-1.
because rate is inversely proprtional to time. AND CONSTANTS HAVE NOT UNITS.

In the mark scheme, the exact word written is "per second"..... But no where is written S^-1. The difference between bot of them is that, the unit would still be per second if you multiply a constant. ( like you said constant does not have any unit)
but at the end you do have to give constant because it might change the magnitude or the uni itself. Like, the constant 100 can change the unit of cm into M if you divide the constant. So, in order to know the magnitude and what is the exact unit, Constant is necessary.

 

[shikha95]

what we made from FB8 was an ester. FB8 was a compound of a carboxylic acid, sodium acetate to be exact.

OMG! I LOVE you Zahra! Your results were all similar to mine, we could be copying off each other!
Yousuf, you‘re a bum...