Chem1010 (1 Viewer)

[zaxmacks]

then why do every still reference to it? Or is it like weak chloroform?

Doctors used to use it before anaesthetics, so it does work.

 

[Icystealer]

Gotta admit the lab was quite fun and i cant wait for more wet labs =D

 

[militiaman]

Did anyone else think the lab was fun?

It was better than I thought it'd be.

Yes! It was actually one of the most enjoyable practical chemistry experiments I've done in ages, beat a lot of the ones we did at school. I especially liked how we go to apply the knowledge we learnt in the first half to the second half which was determining the unknown.

The only problem I had was the instructions were very confusing in the lab manual, but once I figured things out it was actually good to do it largely independent of instruction from the demonstrators.

Doctors used to use it before anaesthetics, so it does work.

Exactly, chloroform will still knock you out, but it is very toxic to us (especially in high doses) and repeated exposure can lead to liver and kidney problems. In saying that it can knock you out, get the wrong dosage and it could kill someone instead.

 

[jumb]

I'm guessing the lab demonstators just lied to us to make sure we didn't start dabbing it on cloth and huffing it.

 

[zaxmacks]

Every one post what labs their in.

Thurs 6pm - 9pm. Go me.

 

[Icystealer]

Monday 1pm - 4pm.

And im freaking struggling with the 2 last questions for the lab report

 

[militiaman]

Wednesday 1-4 but I went to Friday 9-12 last week.

How do you find finishing at 9pm zax?


And those questions are stupid because I'm 99% sure that the answer to the first one at least requires knowledge that we are nowhere near at in the lectures and is unrelated to anything we could have learnt in the lab. I looked up that book by Kotz in the library that they reference and it provides more of a hint than an answer, at least it's not comprehensive, and it's nothing to do with what we've learnt so far.

 

[zaxmacks]

I don't know how to answer Q1, but Q2 is pretty easy. In the experiment we did, the nitrite (NO2) anion gave off a brown gas when reacted with sulfuric acid, and the nitrate (NO3) didn't give off a gas. So if you mixed H2SO4 with the unknown mixture and it gave off a brown gas, you'd know it was KNO3. If KNO3 was the unknown, then it would form a precipitate (with the H2SO4), and if it was Ba(NO3)2, it would dissolve if you used HCl.

And it wasn't too bad finishing up in my lab, I ended up finishing at 7.50.

 

[jumb]

I don't know how to answer Q1...

what is it?

 

[militiaman]

If you remember the experiment: why were sodium salts used in the experiment rather than salts of transition metals (such as Cu)? (or words to that effect)

Since I did Chemistry of Art whenever I hear transition metals I always think of that 3d subshell, electron configuration bs and more complex chemistry, but I'm now thinking that it's probably something simpler. It's a rigged question anyway because like I said, it doesn't relate to anything we've learnt so far. It's even worse because I've heard that some people have just been emailing/contacting their demonstrators who are then giving them perfect answers.

And I checked that Kotz book again today, absolutely useless, if you used the info in the answer it would either be wrong or too vague.

I don't know how to answer Q1, but Q2 is pretty easy. In the experiment we did, the nitrite (NO2) anion gave off a brown gas when reacted with sulfuric acid, and the nitrate (NO3) didn't give off a gas. So if you mixed H2SO4 with the unknown mixture and it gave off a brown gas, you'd know it was KNO3. If KNO3 was the unknown, then it would form a precipitate (with the H2SO4), and if it was Ba(NO3)2, it would dissolve if you used HCl.

I assume 1st KNO3 = KNO2

Why would KNO3 form a precipitate with H2SO4 though? Think you got those last 2 mixed around.

Also that's another stupid thing if we're expected to answer this with solubility rules (which is how I probably will) when we hadn't learnt or done anything like that in the experiment.

 

[zaxmacks]

I assume 1st KNO3 = KNO2

Why would KNO3 form a precipitate with H2SO4 though? Think you got those last 2 mixed around.

Also that's another stupid thing if we're expected to answer this with solubility rules (which is how I probably will) when we hadn't learnt or done anything like that in the experiment.

I wasn't thinking when I wrote that lol.

So the Nitrate salt ions won't react to give a gas (I'm pretty sure), which means that if you get a gas (a brown gas) it'll be the KNO2. If it's KNO3, it'll just dissolve in water, and if it's Ba(NO3)2 it'll form a precipitate.

 

[zaxmacks]

what is it?

"Why are sodium salts used instead of salts of the transition metals (such as Cu^2+) in this experiment?"

Also, why the shit are they telling us to do background reading in a book that isn't the prescribed text for the course? What freaking idiots.

 

[militiaman]

I wasn't thinking when I wrote that lol.

So the Nitrate salt ions won't react to give a gas (I'm pretty sure), which means that if you get a gas (a brown gas) it'll be the KNO2. If it's KNO3, it'll just dissolve in water, and if it's Ba(NO3)2 it'll form a precipitate.

Methinks you are spot on, that's what I'll be putting.

 

[zaxmacks]

Methinks you are spot on, that's what I'll be putting.

That's all in a reaction with sulfuric acid, btw.

 

[emmcyclopedia]

Gotta admit the lab was quite fun and i cant wait for more wet labs =D

YES YES YES!

Computer lab this week was a bit umm... repetitive =/

Every one post what labs their in.

Thurs 6pm - 9pm. Go me.

Tuesday 1pm - 4pm

Monday 1pm - 4pm.

And im freaking struggling with the 2 last questions for the lab report

The back page of my write up was covered in scribbles =P

 

[jumb]

What happened in the labs today? The alarms were going off for atleast an hour and when I left there were a few fire trucks and ambo's parked at the Chem building.

 

[militiaman]

We were doing our 'experiment' in the physics building but our demonstrator said something 'dangerous' had been spilled by someone I think.

Edit: Oh and this week's experiment was the worst. Firstly one of the instructions said to get something from the virtual lab that wasn't there and I had to ask my demonstrator wtf was going on. So that section was screwed, I basically just got all the results from him. Next part I go to drop some of the substance on to the balance (with the paper there of course) and it comes up with this freaking error, so I got all the results for that from the demonstrator as well. Then he tells me I'll need a few other ones in later sections because they're missing. So in the end I think I only got to do a couple of things for my self.

Does anyone know if the test/quiz for this experiment will be on the actual results we got (i.e values and shiz in the experiment) or if it's all just the theory? I know the demonstrator said at least some would be theory based on the first few weeks of lectures and concepts in this experiment, but I wonder if they'll ask us like how many moles were in substance x of the experiment.

 

[Sarah92]

What happened in the labs today? The alarms were going off for atleast an hour and when I left there were a few fire trucks and ambo's parked at the Chem building.

I heard off others that someone burnt plastic.

 

[zaxmacks]

Tuesday 1pm - 4pm

Lucky you, that's the one I wanted/will hopefully move into soon (if someone drops out of it)....

 

[axlenatore]

if you guys have either Chris or Andy as your demonstrator then, youre set they are the best, I had doug for 1010 and he was lazy, haha.

Chris gave me the nickname knob toucher in 1020