Question Chain Thread !!! (1 Viewer)

[JasonNg1025]

Ohk, so it should be alright if we use knowledge from the same topic

 

[danz90]

Ohk, so it should be alright if we use knowledge from the same topic

Yeah, definitely. I reckon its nifty to do that.. it shows your marker you can link concepts from different parts of the module (I suppose).

 

[gcmk]

Yeah, definitely. I reckon its nifty to do that.. it shows your marker you can link concepts from different parts of the module (I suppose).

thats good, i really don't want to spend time memorising and trying to understand a new chemical principle- eg. gas chromatography.

 

[eddy11]

Describe a test that could quantitatively monitor the concentration of phosphate ions in a water supply.

Flow injection analysis is a technology now beginning to be used by various local water authorities to accurately determine the concentration in ppm (ppb for some ions, but not phosphate) of phosphate ions in the water. It works by injecting a reagent into a water sample, the products then flow through to an analyser which determines the concentration and identities of ions in a sample based on their chemiluminescence, absorbance and/or fluorescence which are compared by the analyser to known values to which it has been calibrated.

 

[danz90]

I'm actually thinking of talking about an Analytical Chemist employed by the Sydney Catchment Authority, who performs analytical testing on water samples throughout the catchment area on a daily (or maybe weekly?) basis, testing for levels of heavy metals such as Pb²⁺,Fe²⁺ and others.

Now this part im not 100% sure of:
The chemical principle used by an analytical chemist employed by the SCA, is that different gaseous metallic cations absorb light of different wavelengths. By carefully selecting a correct/appropriate cathode lamp, quick and accurate measurements can be made using AAS, since the gaseous ions will absorb light of particular wavelengths.

Is that more a PHYSICAL property, rather than chemical?

 

[JasonNg1025]

They shouldn't pennalise you for it, it uses knowledge of an atom and the way they react to light. That seems chemical enough

 

[danz90]

They shouldn't pennalise you for it, it uses knowledge of an atom and the way they react to light. That seems chemical enough

lol hope so...

By the way, since I'll be calling up advice line soon...

Is there any particular dot point or topic area we're all concerned about or anything, that I can ask??

 

[JasonNg1025]

There's an advice line? I never knew about that
I thought BOS was kinda like an advice line itself

 

[eddy11]

i do an environmental chemist, they work at ORICA on Botany bay and conduct tests to determine the effects of the ORICA plant on the environment around the harbour and advise on the safe disposal of contaminated waste that is potentially hazardous to the environment, as well as investigate reports of contamination of soil and ground water. He uses analytical chemical methods (gravimetric and volumetric analysis, AAS, FIA), as well as understanding acid base reactions for chemical neutralisation.

Describe the discovery of new elements

 

[danz90]

Yeah, 13 11 12

hey jason, do u know an easy way 2 learn solubility rules?

 

[axlenatore]

lol hope so...

By the way, since I'll be calling up advice line soon...

Is there any particular dot point or topic area we're all concerned about or anything, that I can ask??

Yes please, this



Ive been arguing with teachers for ages variables are related to reliability but both my bio and chem teachers have told me thats its only repeating the experiment

 

[eddy11]

"do u know an easy way 2 learn solubility rules?"


write them over and over and over and over and over and over and over again

as for variables and reliability, they're important in a round-a-bout-way because when you repeat the experiment to achieve reliability, those same variables must be controlled as they were in the first run of the experiment, otherwise the results wont be repeatable thus you cant show that the results are reliable

 

[danz90]

Yes please, this



Ive been arguing with teachers for ages variables are related to reliability but both my bio and chem teachers have told me thats its only repeating the experiment

My teacher has also taught us that reliability is simply attained by the reptition of the same experimental procedure, to obtain a larger sample size of results, upon which a more reliable conclusion can be made.

Variables are related to validity. Validity is achieved when the only factor affecting the dependent variable is the independent variable, i.e. all other influential variables are controlled.

 

[yorkstanham]

What properties of technetium-99m make it more suitable for medical imaging that cobalt-60?

 

[axlenatore]

My teacher has also taught us that reliability is simply attained by the reptition of the same experimental procedure, to obtain a larger sample size of results, upon which a more reliable conclusion can be made.

Variables are related to validity. Validity is achieved when the only factor affecting the dependent variable is the independent variable, i.e. all other influential variables are controlled.

the answer is d though

 

[danz90]

the answer is d though

Maybe I forgot to mention... Reliability also incorporates repeating the experiment using the same procedure.

So perhaps the MORE correct answer is D.

tricky question

 

[axlenatore]

What properties of technetium-99m make it more suitable for medical imaging that cobalt-60?

you wouldnt get a question this specific, as people my not have studied these particular isotopes are the dot point just ask for one used in medicine industry, you would instead get a question why properties of a selected isotope used in medicine make it more suitable then an isotope used in industry for medicinal purposes, but then that is still too broad and evil

 

[yorkstanham]

you wouldnt get a question this specific, as people my not have studied these particular isotopes are the dot point just ask for one used in medicine industry, you would instead get a question why properties of a selected isotope used in medicine make it more suitable then an isotope used in industry for medicinal purposes, but then that is still too broad and evil

just answer the question!

 

[JasonNg1025]

hey jason, do u know an easy way 2 learn solubility rules?

I dunno... just try and remember the "1" ones... generally the +- 1s in the periodic table are soluble.

I like to imagine very ridiculous things to remember it, cause they somehow stick in my head.

So once I see a metal from group one I immediately think of stuff dissolving. I don't know why, but once I see an alkali ion my brain just switches to "dissolve, dissolve, dissolve"

From there, I think "wait, anything similar should also dissolve and hence ammonium salts should dissolve"

Then I think "if that works then other 1s should also dissolve, such as the halogens, NO₃ and CH₃COO"

Sulfates are soluble cause they both start with S . But sulfides aren't because the sulfide group is purely sulfur, sulfur does not dissolve.

Think of silver, lead and mercury as antagonists... they make dissolving impossible for halogens and sulfates.

I don't know how to remember hydroxides and oxides, they're insoluble, if you keep worrying about it it may just stick in

Exceptions -

Barium and calcium - they love reversing things. Reversed from above rules for sulfates, hydroxides, oxides. Remember your chain of thought: you think of group 1 first, group 1 gets priority. All group 1s and ammonium salts are exceptions to the "insoluble" groups.

Took my ages to write, sorry

 

[danz90]

What properties of technetium-99m make it more suitable for medical imaging that cobalt-60?

- Technetium-99m has a half life of 6 hours, and releases low energy gamma radiation, while Cobalt-60 has a half life of 5.3 years and releases high-energy gamma radiation. Hence, technetium-99m would allow for accurate, precise medical imaging, without exposing the body to harmful levels of radiation for extended periods of time, since it has a very short half-life in comparison to cobalt-60.

Also, Technetium-99m has multiple oxidation states, meaning it can be used in a wide variety of diagnostic scanning, including brain, bone and renal scanning, since Tc-99m can attach to a wider variety of organic molecules, than Co-60 can.