chemistry 1/2 questions thread

[Einstein]

just got my exam score back and got low 80s, despite scoring mid 90s all year in SACs. Though i do have a excuse, i had a 3/4 sac on the day of the exam, but i dont know if that would be good enough to compensate for my score.

Im really shattered now, the fact that i got that score (my standards are higher), but it is 1/2 after all. Is it worth going over the things i got wrong, i know that i lost a few marks for not knowing ions, but other then that id suspect things to be stupid mistakes. I only studied the week before really briefly and on the day of the exam for 1 and a half hours.

Thanks

[alchemy]

just got my exam score back and got low 80s, despite scoring mid 90s all year in SACs. Though i do have a excuse, i had a 3/4 sac on the day of the exam, but i dont know if that would be good enough to compensate for my score.

Im really shattered now, the fact that i got that score (my standards are higher), but it is 1/2 after all. Is it worth going over the things i got wrong, i know that i lost a few marks for not knowing ions, but other then that id suspect things to be stupid mistakes. I only studied the week before really briefly and on the day of the exam for 1 and a half hours.

Thanks

Wait, this is a questions thread right? What's your question?

[IndefatigableLover]

Wait, this is a questions thread right? What's your question?

just got my exam score back and got low 80s, despite scoring mid 90s all year in SACs. Though i do have a excuse, i had a 3/4 sac on the day of the exam, but i dont know if that would be good enough to compensate for my score.

Im really shattered now, the fact that i got that score (my standards are higher), but it is 1/2 after all. Is it worth going over the things i got wrong, i know that i lost a few marks for not knowing ions, but other then that id suspect things to be stupid mistakes. I only studied the week before really briefly and on the day of the exam for 1 and a half hours.

Thanks

But seriously to answer your question, I think you should be content with your score. You know where you went wrong so check if it's a necessary part of the VCE course (which memorising ions is) so you will need to know your ions properly.

[alchemy]

lol, i didn't see that...
The number of people complaining here about the relatively high scores they get is too damn high! 

[RazzMeTazz]

Does water have a higher heat capacity than most other common molecular substances?

[jgoudie]

Yes.  One real life explanation for this is the beach on a hot day.  During the day: the sand gets hot, the water stays cool. At night: the sand cools quickly, the water stays the same temperature.

Another good example is oil and water. Put a cup of each on the stove and see which one gets hotter quicker.  (oil wins every time)

Waters SHC is 4.18, most other things are around 2 and below.

(yeah i know there are currents and all that jazz in play as well, but you get the idea)

Does water have a higher heat capacity than most other common molecular substances?

[RazzMeTazz]

This might sound silly,

But why is water not a polyatomic ion?

The molecule itself has 10 protons and 8 electrons,

Shouldn't it be positively charged then?

[RazzMeTazz]

Can the hydrogen atom in a hydroxyl group form hydrogen bonds with other molecules in which hydrogen is attached to a N,O or F?

[IndefatigableLover]

This might sound silly,

But why is water not a polyatomic ion?

The molecule itself has 10 protons and 8 electrons,

Shouldn't it be positively charged then?

Well Hydrogen has one proton and one electron and then Oxygen has 8 Protons and Electrons so in the end the molecule itself has 10 Protons and 10 Electrons making it neutrally charged (I think you're forgetting about the lone pairs)?

Can the hydrogen atom in a hydroxyl group form hydrogen bonds with other molecules in which hydrogen is attached to a N,O or F?

I'm pretty sure that it can!

[RazzMeTazz]

Well Hydrogen has one proton and one electron and then Oxygen has 8 Protons and Electrons so in the end the molecule itself has 10 Protons and 10 Electrons making it neutrally charged (I think you're forgetting about the lone pairs)?
I'm pretty sure that it can!

Oh thanks so much!

That makes sense now!

[RazzMeTazz]

When writing precipitation reactions and a particular compound is slightly insoluble, what do you consider it to be when writing states, soluble or insoluble?

[alchemy]

When writing precipitation reactions and a particular compound is slightly insoluble, what do you consider it to be when writing states, soluble or insoluble?

Slightly insoluble still means it's insoluble.

[Yacoubb]

Can the hydrogen atom in a hydroxyl group form hydrogen bonds with other molecules in which hydrogen is attached to a N,O or F?

The hydrogen atom on a hydroxyl (-OH) and carboxyl (-COOH) group is capable a forming a hydrogen bond with F, O or N.

[MNM101]

How would u calculate the volume in mL and mass of KMnO4  dissolved in a solution(500mL) flask. It says that 0.5 g of KMnO4 is supposed to be dissolved but that's where it's confusing me a bit.

[jgoudie]

By the looks of it you haven't written out the full question and some information is missing.  For these types of questions you need to work with the following equations:

m=n.Mr
n=c.V

If you think about whatever the question is asking and transpose these equations you should be able to come up with something. 

Alternatively post the full question on here.

How would u calculate the volume in mL and mass of KMnO4  dissolved in a solution(500mL) flask. It says that 0.5 g of KMnO4 is supposed to be dissolved but that's where it's confusing me a bit.