Are you trying to answer my question....?
Just started re-studying chem tonight after business. Ease me in with a few moderate questions (not too hard)? <3
Explain why models are useful in chemistry. [2]
lol guess I really do know nothing from module 3.
Hahahaha
Yeah, I only learnt this today after HeroicPanda Skyped me the question haha.
Isn't that from last year's exam paper. It is highly unlikely they will ask that question this year.
since when was sulfuric acid (dehydrating agent) considered a catalyst?
Might as well repeat Chem ayemoey never knew H2SO4 was a catalyst(
Clearly state that ethane does not have a double bond.
ethane (C2H6) is a gas with a single bond between the carbons, it is considered saturated and cannot undergo addition reactions due to this property. ethane has a lower BP than ethene due to smaller amounts of dispersion forces (is this right??)
1) lol i've got no idea for this one but I'll try:Here's some questions for the rote learners:
1)Describe how to qualitatively check for the presence of nitrates and phosphates
2)Describe how to quantitatively measure the amounts of nitrates and phosphates
Since not many people know the second part (a few don't know the first part) I'll post my solutions. By no means is it the perfect answer, it's just my answer (which is usually incorrect)Here's some questions for the rote learners:
1)Describe how to qualitatively check for the presence of nitrates and phosphates
2)Describe how to quantitatively measure the amounts of nitrates and phosphates
It should be in the syllabus.
Since not many people know the second part (a few don't know the first part) I'll post my solutions. By no means is it the perfect answer, it's just my answer (which is usually incorrect)
1)Qualitative test for phosphate: The presence of phosphate is indicated by a yellow ppt with ammonium molybdate
Qualitative test of nitrate: The presence of nitrate is indicated by the Brown Ring Test where FeSO4 is added to a water sample then concentrated sulfuric acid. If a brown ring forms at the junction, nitrate is present.
2)Quantitative test for phosphate: A sample of the water is mixed with ammonium molybdate and Vitaman C (ascorbic acid) which produces an intense blue colour. This colour can be compared against known standard solutions to come up with an approximation.
Quantitative test of nitrate: Nitrate ions are reacted with a reductant to form nitrite ions. These nitrite ions react with colour reagents to produce pink/purple dye which is compared against known standards.
gather, process and present information on the range and chemistry of the tests used to:
)
I used the tests for BOD and DO for this. Is that wrong...?gather, process and present information on the range and chemistry of the tests used to:
identify heavy metal pollution of water
monitor possible eutrophication of waterways
Hmm it looks like you can choose which tests you want, I thought it'd be in the syllabus because it was in my book (well at least you guys learnt a new test
No idea tbh