[Jabus]

Alright, so I'm brushing up on chemistry which I haven't done in roughly, 5 years or so. And when I did take it, it was grade 11 and let's just say I wasn't a top notch student back then...

Anywho I'm working on some questions which I've got answers for I was hoping someone could point out either which ones are wrong and perhaps get me started on some of the ones that are wrong. Any help would be great. I'm not sure if this forum allows linking images so let me now and I'll just change them up into links. But basically this is how far I've gotten using pretty much wikipedia. But I'm not really 100% sure of what terms I'm searching for (ie double displacement i think i found out about randomly).

I know it's a few questions, but hopefully there's some who can take a look at those, they are pretty basic so I'm sure some of you will end up breezing by them.

Thanks in advance for any *delete me*

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Edit: Modified title and images to links

[biospy]

Ok, I looked over the first set of answers. Some consistent difficulties were that you didn't put a charge for many of the ions. All of the second part should have charges. Also, stock system nomenclature seems challenging for you. You don't know when to use it and when not to use it.

Please repost answers for

5
g, h, i

6 All for charges, a few for other answers

7
a, d, e, g, h, l

If you repost corrected answers, I will check them and then I can check the other sets of problems.

[Jabus]

Hey,

Thanks for replying I re-checked some of my answers and these are the modified ones I noticed.

5 g) MnIO2
h) WF6 (careless mistake of making it Fl thinking of Cl)
i) This one was odd, according to the brief text (all 4 pages of it) HFO is correct for Hypofluorous Acid. I did some searching online however, and found out it is being listed as HOF. Any particular reason that is the case (some rule I should know about maybe O's follow H's, I'm not sure).

6) I did some searching under polyatomic ion charges and how to find their charges, unfortunetly I cannot come across a page that explained it well enough. All the pages I seem to hit are ones with lists already made for what the charge of x polyatomic is. http://dl.clackamas.edu/ch104-07/polyatom1.htm - this was the best site I could locate but I'm clearly doing something wrong with my Lewis diagram since i'm getting 30 on the SO4 diagram and 28 accounted for which leaves me with a +2 rather than -2 charge. Is there a better definition of how to determine charge? As for the actual answers I did eventually give up searching and just one of the 'already given charge' lists out there http://en.wikipedia.org/wiki/Polyatomic_ion to determine the answers should be as follows (but I would much rather understand how that list was derived otherwise I wont know what I'm doing in any future questions:

6a) So3  -2
b) OH   -
c) NO3    -
d) H2PO4   -2
e) H2SO4    -
f) I see my mistake here it should read IO4    -
g) CO3    -2
h) H2PO2    -3
i) FO3    -
j) (also see this why this one was wrong) BrO2   -

So the formulas that were wrong I spotted and fixed, however what charge each one should be is still a mystery to me and hopefully someone can help me out on that.

7)a) I continued to have trouble with polyatomic atoms, I think I just need to find a good tutorial on what happens with multiple atom configurations. The roman numerals I had simply learned to take the subscript of the right side and place it as the roman on the left that doesnt seem to work for poly atomic. so...I dont know d, e) should be Calcium dihride g I dont know h...Manganese (IV) dioxide (or II...i think its IV because Manganese is +2 and there are 2O with -2). Finally l) I'm not quite sure about looking at it, maybe it is just Lithium Oxide with no numerals. (dilithium oxide?).

So, am I a lost cause or can someone help me figure out this polyatomic ion business i seem to be having trouble with?

[biospy]

ok, good for number 5
for i, I was just thinking the order was different..it doesn't make a difference really so no need to worry about that

for number 6, I think it's better to just memorize the charges...remember NO SO PO.....CO CrO ClO

and you'll be okay

for stock system nomenclature, use your periodic table. if only one oxidation state given, it has only one charge possible

the multiple state ones that are most common are copper, iron, lead, can't think of what others offhand but there really arent too many. and be sure that you don't use them for molecular compounds...ionic only

[Will]

Also answers for 5 k) and m) need redoing.
And from 9- b) c) d) f) and h) need redoing. (g doesn't need heat in the equation, lots of reactions are exothermic)
The equation you wrote for 10 also needs correcting. Look up the formulas for sodium sulfate and water .

[Jabus]

Also answers for 5 k) and m) need redoing.
And from 9- b) c) d) f) and h) need redoing. (g doesn't need heat in the equation, lots of reactions are exothermic)
The equation you wrote for 10 also needs correcting. Look up the formulas for sodium sulfate and water .

5.k) H2S (woops!)
m)...isn't Phosphorus just the Phosphorus atom, thus P?

6 Im guessing after fixing the 2 plus all the charges seems mostly right.

7a) Zinc Iodide (I)
d) Iron (II) Sulphite since sulphite has a -2 charge
g) Copper (I) Nitrate due to nitrate being a -1 charge (wow these are slightly easier after doing 6 hah)
h) Manganese (IV) dioxide
l) Dilithium monoxide

Not sure about the last one but im a bit more confident in the rest of the answers. I would still like to find out how to find out the number 6 ones are negative or positive charges, just for the sake of knowing (if anyone would like to go over that).

For questions in 9, before attempting them again, I was just hoping someone can push me in the right direction of what to read up on. The only formula I was using for balancing these was AB + CD -> AD + CB

So as of right now I wouldn't be sure where to begin to identify how to solves the incorrect ones. How do I know what reactants will occur, just by knowing the products, are there certian rules to apply?

Thanks for all the help so far.

[Jabus]

Ok, finally had some spare time to learn/go over these a bit more, here are my new answers for 9:

9a) was deemed right alread
b) Au2(SO4)3 + 3BaCl2 --> 2AuCl3 + 3BaSO4
c) Zn + 2HgNO3 --> Zn(NO3)2 + 2Hg
d) 5Sn + 2SbCl5 --> 5SnCl2 + 2Sb
e) Ca + 2H2O --> Ca(OH)2 + 2H2
f) 3 FeBr2 + 2H3PO4 --> Fe3(PO4)2 + 6HBr
g) was all correct I hope
h) CaCO3 + 2HBr --> CaBr2 + H2O + CO2

And to this I also wanted to add my answer to 10a) (which actually appears on this forum at this link http://www.chemicalforums.com/index.php?board=4;action=display;threadid=6574 but I got this)

How many grams of H2SO4 will neutralize 10.0g of NaOh?

H2SO4 + 2NaOH --> 2H2O + 2NaSO4

Couldn't I just do

10.0g/80.0gmol (NaOH)  |||   x / 98.1 g/mol

Solve for x which is 12.3g and thus 12.3 g would be need of H2SO4 to neutralize NaOH?

[Borek]

e) Ca + 2H2O --> Ca(OH)2 + 2H2

Check it.

And try EBAS to check other answers in the future (copy equation to clipboard and press Ctrl-F variant - that's how I have checked your equations now in less then a minute; not that I have not seen they are OK/NOK at the first sight, they are relatively simple ).

10.0g/80.0gmol (NaOH)  |||   x / 98.1 g/mol

Solve for x which is 12.3g and thus 12.3 g would be need of H2SO4 to neutralize NaOH?

OK (see using ratios for stoichiometry calculations).

[Jabus]

OK (see using ratios for stoichiometry calculations).

Good link.

e) Ca + 2H2O --> Ca(OH)2 + 2H2
Ah yes, that must have been me not paying attention.
Ca + 2H2O --> Ca(OH)2 + H2

Thanks for the help.