James Ruse Trial Question (1 Viewer)

[Ambility]

This is a screenshot from an answer sheet of a James Ruse paper. Apparently, the correct answer is B (bolded), but I believe the correct answer is A. Could someone explain why B is correct?

 

[Ambility]

http://i.imgur.com/VjeFFez.png

Why is this c? How would you even work it out?

 

[Ambility]

http://i.imgur.com/6Iw5vro.png

Also, how would you work out this?

 

[Shuuya]

http://i.imgur.com/VjeFFez.png

Why is this c? How would you even work it out?

For elements up to about 20, the neutron: proton ratio should be about 1. For larger elements until about 83, the neutron: proton ratio should be about 1.5 for stable elements.

In the case of c), there are 20 neutrons and 17 protons, which is about 1.17, meaning that the ratio of neutrons: protons is too high. I pretty much went through all the options and checked the ratios

 

[Shuuya]

http://i.imgur.com/6Iw5vro.png

Also, how would you work out this?

For this one you need to know the solubility rules. If Pb2+ was present, then it would react with Cl- to form insoluble PbCl2. All the other ions produce soluble compounds with Cl-

 

[porcupinetree]

View attachment 32876

This is a screenshot from an answer sheet of a James Ruse paper. Apparently, the correct answer is B (bolded), but I believe the correct answer is A. Could someone explain why B is correct?

Note that the question asks for the IUPAC name of an isomer of the compound, not the name of the actual compound itself.

http://i.imgur.com/VjeFFez.png

Why is this c? How would you even work it out?

On our periodic table, we can see that the average mass of a chlorine atom is 35.45 amu (atomic mass units). In option C, we have 37 atomic mass units, indicating that we are dealing with a isotope with more neutrons than usual; hence our neutron : proton ratio is too high.
Also, all the other options are wrong, if you employ a similar method of thinking.

http://i.imgur.com/6Iw5vro.png

Also, how would you work out this?

Both lead (II) sulfate and lead (II) chloride are insoluble.

 

[Ambility]

Sigh....

Do I need to memorise the solubility table? I don't think it is on the data sheet.

 

[Shuuya]

Sigh....

Do I need to memorise the solubility table? I don't think it is on the data sheet.

Yep we have to memorise it

 

[Ambility]

Note that the question asks for the IUPAC name of an isomer of the compound, not the name of the actual compound itself.



On our periodic table, we can see that the average mass of a chlorine atom is 35.45 amu (atomic mass units). In option C, we have 37 atomic mass units, indicating that we are dealing with a isotope with more neutrons than usual; hence our neutron : proton ratio is too high.
Also, all the other options are wrong, if you employ a similar method of thinking.



Both lead (II) sulfate and lead (II) chloride are insoluble.

Thanks, I didn't realise that it was an isomer...

 

[Ambility]

Yep we have to memorise it

That really sucks haha, I'd better get to it.

Thanks heaps guys.

 

[porcupinetree]

Sigh....

Do I need to memorise the solubility table? I don't think it is on the data sheet.

You should also remember/memorise specific details about specific precipitates, e.g. BaSO4 is fine & white, PbI2 is bright yellow, etc

 

[Ambility]

You should also remember/memorise specific details about specific precipitates, e.g. BaSO4 is fine & white, PbI2 is bright yellow, etc

rote, rote, and more rote.

I signed up for it though.

 

[InteGrand]

rote, rote, and more rote.

Spot on!

 

[leehuan]

rote, rote, and more rote.

I signed up for it though.

Spot on!

Wow... It's still way more fun than the rote in biology...

 

[InteGrand]

Wow... It's still way more fun than the rote in biology...

But memorising colours isn't that fun, is it? That's basically just a pointless test of memory.