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Re: Density Lab B

Posted: February 20th, 2020, 12:33 pm
by astronomybuff
Wow, thanks!
It makes a lot of sense now. As for the chemistry, it's not that much because you should be expected to have a periodic table in your binder.
Anyways, thanks for the help!

Re: Density Lab B

Posted: February 20th, 2020, 2:17 pm
by knightmoves
astronomybuff wrote: February 20th, 2020, 12:33 pm Wow, thanks!
It makes a lot of sense now. As for the chemistry, it's not that much because you should be expected to have a periodic table in your binder.
Anyways, thanks for the help!
Having a periodic table? Maybe, although I think you're stretching. Knowing that aluminum chloride is AlCl_3 is most definitely chemistry, and beyond any reasonable interpretation of the density lab syllabus.

If you were given the balanced equation as part of the question, and I think also given a periodic table or a list of atomic masses, then it would be fair game.

Re: Density Lab B

Posted: February 20th, 2020, 8:56 pm
by NSCDS3RdCaptain
Hi,
I have some questions from a test that my team took recently took:
The IPK is weighed at the BIPM in Paris whilst submerged in water. What will it weigh
under these conditions? My confusion here is how to find this without the volume of the IPK, which I would not expect to be in a binder.
How would you find the mass of an object with unknown density using Archimedes' principle? Why would this work?
Thanks so much!

Re: Density Lab B

Posted: February 21st, 2020, 12:26 pm
by knightmoves
NSCDS3RdCaptain wrote: February 20th, 2020, 8:56 pm Hi,
I have some questions from a test that my team took recently took:
The IPK is weighed at the BIPM in Paris whilst submerged in water. What will it weigh
under these conditions? My confusion here is how to find this without the volume of the IPK, which I would not expect to be in a binder.
How would you find the mass of an object with unknown density using Archimedes' principle? Why would this work?
Thanks so much!
Was there no more information given? You know the mass of the IPK, of course, but you need to know either volume or density to be able to answer the question. This reads like a later part of a multi-part question - I'm not sure I'd expect people to be able to expand the IPK acronym without more context.

Re: Density Lab B

Posted: February 21st, 2020, 12:57 pm
by NSCDS3RdCaptain
There was no other information given. I literally copied and pasted the problem.

Re: Density Lab B

Posted: February 21st, 2020, 1:45 pm
by knightmoves
NSCDS3RdCaptain wrote: February 21st, 2020, 12:57 pm There was no other information given. I literally copied and pasted the problem.
Well, if it's not part of a multi-part question where either the volume or the density of the IPK was given in a previous part, then it's impossible (unless someone magically has that bit of trivia in their binder, but an ES hoping people know that is too silly for words.) And, frankly, assuming that people will correctly unpack "IPK" with no additional context is a bit much, too, so I'm still wondering whether this wasn't part b of a two-part question or something.

If the volume or density of the IPK was given in an earlier part of the question, then it's fair game (and quite straightforward).

Re: Density Lab B

Posted: February 21st, 2020, 1:51 pm
by azboy1910
Yes, I agree.

Although, I did find that IPK stands for International Prototype of the Kilogram, but I am not sure if this will help solve the problem.

An attached link is found here: https://www.bipm.org/en/bipm/mass/ipk/

Re: Density Lab B

Posted: February 21st, 2020, 2:13 pm
by azboy1910
Yes, I agree.

Although, I did find that IPK stands for International Prototype of the Kilogram, but I am not sure if this will help solve the problem.

An attached link is found here: https://www.bipm.org/en/bipm/mass/ipk/

Re: Density Lab B

Posted: February 25th, 2020, 7:50 am
by knightmoves
NSCDS3RdCaptain wrote: February 20th, 2020, 8:56 pm I have some questions from a test that my team took recently took:
The IPK is weighed at the BIPM in Paris whilst submerged in water. What will it weigh
under these conditions? My confusion here is how to find this without the volume of the IPK, which I would not expect to be in a binder.
How would you find the mass of an object with unknown density using Archimedes' principle? Why would this work?
Was this from Kildeer?

As it happens, I was asked about a question from Kildeer that sounds very much like this one yesterday. In that test, the question you quote here was part c of a three-part question, and the density of the IPK was given in part b of the question (as 21.54 g cm^-3 for anyone playing along at home). Earlier in the question, International Prototype Kilogram was spelled out in full.

So I think placed in that context, it's not too hard.

Re: Density Lab B

Posted: February 28th, 2020, 5:59 am
by NSCDS3RdCaptain
No.
knightmoves wrote: February 25th, 2020, 7:50 am [quote=NSCDS3RdCaptain post_id=410937 time=<a href="tel:1582261004">1582261004</a> user_id=46266]
I have some questions from a test that my team took recently took:
The IPK is weighed at the BIPM in Paris whilst submerged in water. What will it weigh
under these conditions? My confusion here is how to find this without the volume of the IPK, which I would not expect to be in a binder.
How would you find the mass of an object with unknown density using Archimedes' principle? Why would this work?
Was this from Kildeer?

As it happens, I was asked about a question from Kildeer that sounds very much like this one yesterday. In that test, the question you quote here was part c of a three-part question, and the density of the IPK was given in part b of the question (as 21.54 g cm^-3 for anyone playing along at home). Earlier in the question, International Prototype Kilogram was spelled out in full.

So I think placed in that context, it's not too hard.
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