The Acidic Environment!!!help! (1 Viewer)

[JUB JUB]

I desperately need information on these 3 dot points....
i'll be willing to trade my info on anything else...

Gather and process information from secondary sources to trace developments in understanding and describing acid/base reactions


Analyse information from secondary sources to assess the use of neutralisation reactions as a safety measure or to minimise damage in accidents or chemical spills.


plz help thanx

 

[countrydude]

Hey dude, i am accully doing the first dot point you are having troubles with now for my summary, It might be worth a look at HSC online

http://www.hsc.csu.edu.au/chemistry/core/acidic/chem934/chem934net.html#net13

You will probbaly find the otheres there too, Good luck

BTW that second DP looks like a titration..i havent done it yet

 

[ND]

Originally posted by JUB JUB

Perform a first hand investigation to determine the concentration of a domestic acidic substance

Why not just put in a pH meter?

 

[ballerinabarbie]

Originally posted by ND
Why not just put in a pH meter?

that would be just determining the pH, not the concentration

 

[jm1234567890]

Originally posted by ballerinabarbie
that would be just determining the pH, not the concentration

if you knew equlibriuim constant you could use ph meter

 

[mitochondria]

Titration

(you could do it by weight for a mixture..)

 

[+:: $i[Q]u3 ::+]

it's volumetric titration - you would have done it in class - either aspirin or vinegar.

acids/bases can be very corrosive so neutralisation reactions can be used to.. um.. neutralise it and so reduce the danger... (??)
sodium carbonate or sodium hydrogen carbonate can be used for acidic spills (it's less toxic than NaOH and can be obtained in safe, solid form that's easily stored)
for basic spills, u can use the sodium hydrogen carbonate..again... i think.. can someone back me up on this? i'll come back tmrw when i haf my notes and make sure it's okay.

 

[t-i-m-m-y]

btw we spilled concentrated (18M) H2SO4 (sulfuric acid) on the benchtop; that was fun- it ate away the benchtop

yeah excel has the volumetric titration for concentration of acetic acid in vinegar (domestic substance)- fairly simple, just neutralise, record and calculate

 

[ND]

Originally posted by ballerinabarbie
that would be just determining the pH, not the concentration

But the pH is a measure of the H+ ion concentration.

 

[Bannanafish]

the question is the concentration of the acid, and since you might not be using a strong monoprotic acid, it will be different to concentration of H+

 

[ND]

Originally posted by Bannanafish
the question is the concentration of the acid, and since you might not be using a strong monoprotic acid, it will be different to concentration of H+

Yeh true if it's weak, it doesn't work. But it doesn't have to be monoprotic, well in reality it does, but in the course we assume that even diprotic strong acids ionise completely.

 

[mitochondria]

Originally posted by +:: $i[Q]u3 ::+
it's volumetric titration - you would have done it in class - either aspirin or vinegar.

acids/bases can be very corrosive so neutralisation reactions can be used to.. um.. neutralise it and so reduce the danger... (??)
sodium carbonate or sodium hydrogen carbonate can be used for acidic spills (it's less toxic than NaOH and can be obtained in safe, solid form that's easily stored)
for basic spills, u can use the sodium hydrogen carbonate..again... i think.. can someone back me up on this? i'll come back tmrw when i haf my notes and make sure it's okay.

yup, titration is usually a volumetric analysis for solutions, that is, those you have mentioned. However, when you have mixtures such as orange juice, it is almost impossible/very difficult to do a volumetric analysis "accurately". In one of our prac test we had to do a titration of orange juice to identify the percentage of citric acid (well.. not to mention vitamin C.. but it's only high school chemistry ) - when you think about it, you really can't do it with all these pulps and stuff in it..

and.. here's my backup, NaHCO3 is amphiprotic, therefore it is good for both acid and base neutralisations as it establishs an equilibrium eventually.

*I think* (finally...) if you overdose NaOH when you are neutralising an acid spill.. you will end up having a base spill and this doesn't happen to NaHCO3..


ooh... here's a personal question - where have you been all this time (well.. i see you are always here)? have you ever recieved my e-mails, at all?

 

[+:: $i[Q]u3 ::+]

couldn't u just strain out the pulp, then dilute down the orange juice so it was really pale and the change in indicator colour could be seen?
haha.. okay so maybe the pracs in the textbook don't work so well after all..

 

[mitochondria]

no no no.. this is the problem you see, if you filter it it won't really work because it's a mixture and you are doing it by weight.

try this and you will understand:
1. get an orange
2. make orange juice with it (don't filter out the pulp) in a clear class
3. don't drink it!
4. leave it there for say.. 5- 10 minutes and see what happens

and.. yes, we did dilute the orange juice so the colour change is easier to be seen but we didn't filter the orange juice in the first place. this is also the reason why adding deionised/distilled/demineralised water does not matter because whatever the amount of citric acid there is (technicallly it does make a slight difference in some cases depending on the salt that is formed), all of it is going to react with the base you are adding to it anyway (think about Le Chatelier's principle).. so yeah.. and keep in mind that different parts of orange juice can contain citric acid okay... makes sense?


(not related to anything i've just said) still.. i'm sorry..