Another Topscore Gen Chem question

[mmoosavi41]

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Identify the INCORRECT statement based on the results of the following reactions:

Reaction I. NH3 (aq) + HCl (aq) -->
Reaction II. BaCO3 (s) + HCl (aq) -->
Reaction III. NaF (aq) + Ba(NO3)2 (aq) -->

A. Reaction I is an acid-base reaction

B. The net ionic equation for Reaction III is: 2 F- (aq) + Ba2+ (aq) --> BaF2(s)

C. Reaction II is a gas forming reaction

D. The sum of the coefficients of the balanced net ionic equation for reaction II is 6

E. None of these

Its easy to figure out that A is true but if someone can explain about choices B, C, and D, it would be greatly appreciated. Thanks!

 

[herkulease]

reaction 2: BaCO3(s) + 2HCl(aq) -> BaCl2 + H2O + CO2(g)

reaction 3: 2NaF (aq) + Ba(NO3)2 (aq) -> Na2(NO3)2(aq) + BaF2(s)

for reaction 3 write all the aqueous compounds in ion form then cancel things that are identical on both sides and you'll be left with the net ionic equation seen in choice B. Do the same for reaction 2 and you'll get choice D and from the overall you already see choice C.

 

[nimman1126]

So the correct answer is "E", All are correct?

 

[Molarcule]

How did you get the ionic equation for reaction 2? I'm stuck

Ba2+ +CO3+H+Cl--> BaCl2 + H20 + CO2

 

[bharat008]

How did you get the ionic equation for reaction 2? I'm stuck

Ba2+ +CO3+H+Cl--> BaCl2 + H20 + CO2

BaCl2 is insoluble so it forms a solid. Refer to the solubility chart
H2CO3 breaks down into H20 and CO2..

 

[Jab1113]

Is E all the above or none of the above?

 

[Jab1113]

reaction 2: BaCO3(s) + 2HCl(aq) -> BaCl2 + H2O + CO2(g)

reaction 3: 2NaF (aq) + Ba(NO3)2 (aq) -> Na2(NO3)2(aq) + BaF2(s)

for reaction 3 write all the aqueous compounds in ion form then cancel things that are identical on both sides and you'll be left with the net ionic equation seen in choice B. Do the same for reaction 2 and you'll get choice D and from the overall you already see choice C.

Howd you know that Na2(NO3)2(aq) was aqueous?

 

[bharat008]

Howd you know that Na2(NO3)2(aq) was aqueous?

b/c all nitrates are soluble

 

[nimman1126]

How is BaCl2 not soluble? Solubility rules state Br, Cl and I are insoluble if they are paired with Hg, Pb or Ag right?

 

[herkulease]

How is BaCl2 not soluble? Solubility rules state Br, Cl and I are insoluble if they are paired with Hg, Pb or Ag right?

yes that is correct. all halides are soluble except with Ag+, Pb2+, Hg2+

here is the complete stuff for reaction 2

BaCO3(s) + 2H+ + 2Cl- -> Ba2+ + 2Cl- + H2O(l) + CO2(g) <--ionic

BaCO3(s) + 2H+(aq) -> Ba2+(aq) + H2O(l) + CO2(g) <--net ionic

oh and yes it is choice E for this question.

 

[goldenfeelings]

still confused about reaction 2 - i understand how you broke out the ionic and net ionic equations, but then don't the coefficients in the net ionic equation only add up to 2, not 6? (ionic equation adds up to 6, but net ionic adds up to 2, as far as I can see). Choice D refers to the sum of the coefficients of the "balanced net ionic equation".

The TopScore test does indicate that choice E (none of the above are incorrect) is in fact correct.

really puzzled by this one - hopefully you can clarify - thanks!

 

[herkulease]

still confused about reaction 2 - i understand how you broke out the ionic and net ionic equations, but then don't the coefficients in the net ionic equation only add up to 2, not 6? (ionic equation adds up to 6, but net ionic adds up to 2, as far as I can see). Choice D refers to the sum of the coefficients of the "balanced net ionic equation".

The TopScore test does indicate that choice E (none of the above are incorrect) is in fact correct.

really puzzled by this one - hopefully you can clarify - thanks!

Are you sure not having a numerical coefficient means that it is zero?

I'm intentionally not tell you the answer as you bet can you if you get a question asking you about sum of coefficients one of the answer choices will be the result of the same mistake you made. They'll even tell you not to forget.

 

[goldenfeelings]

Oh - it's not balanced is it...

BaCO3(s) + 2H+(aq) -> Ba2+(aq) + H2O(l) + CO2(g)

balances to:

2BaCO3(s) + 4H+(aq) -> Ba2+(aq) + 2H2O(l) + 2CO2(g)

right? which adds up to 10?

 

[herkulease]

Oh - it's not balanced is it...

BaCO3(s) + 2H+(aq) -> Ba2+(aq) + H2O(l) + CO2(g)

balances to:

2BaCO3(s) + 4H+(aq) -> Ba2+(aq) + 2H2O(l) + 2CO2(g)

right? which adds up to 10?

No it was completely balanced as I wrote it. the thing that I wanted you to remember/know is just because 1 is not written doesn't mean its 0.

1BaCO3(s) + 2H+(aq) -> 1Ba2+(aq) + 1H2O(l) + 1CO2(g)

 

[goldenfeelings]

Oh geez. Just got it.

Thanks!

 

[vash429]

I am a bit weak on the dissociation and balancing equations right now, any tips or something I can do a quick refresher on.