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Practice tests

Posted: January 8th, 2019, 6:11 am
by Scioly2443
Does anybody have any practice test links they can give me? I cannot find any tests for this event.

Re: Practice tests

Posted: January 8th, 2019, 6:33 am
by MattChina
Scioly2443 wrote:Does anybody have any practice test links they can give me? I cannot find any tests for this event.
Theres a couple on the test exchange.

Re: Density Lab B

Posted: January 8th, 2019, 12:29 pm
by UTF-8 U+6211 U+662F
Incineroar999 wrote:Hello. I'm a newbie and I have NO IDEA what I'm doing! Please help!!
I would recommending just looking up all the terms on the rules. All of them are bound to have been covered in great detail on the Internet.

Re: Density Lab B

Posted: January 14th, 2019, 12:28 pm
by Incineroar999
D=m/v
Lmao MattChina

Re: Density Lab B

Posted: January 29th, 2019, 10:56 am
by Srama
If I want to follow Guideline 3.B which states that answer should be in metric and approximate significant figures, Can anyone tell me how would you express the final answer for Boyles law problem.


Also, Is the answer expected to be adjusted to scientific notation for full credits?


For Eg:A container holds 2L of helium. When the pressure is reduced to 2.5 atmospheres and the volume in the container increases to 12L, what was the initial pressure exerted on the container?

Re: Density Lab B

Posted: January 29th, 2019, 11:43 am
by John Richardsim
Srama wrote:If I want to follow Guideline 3.B which states that answer should be in metric and approximate significant figures, Can anyone tell me how would you express the final answer for Boyles law problem.


Also, Is the answer expected to be adjusted to scientific notation for full credits?


For Eg:A container holds 2L of helium. When the pressure is reduced to 2.5 atmospheres and the volume in the container increases to 12L, what was the initial pressure exerted on the container?
Don't forget what 3.B. says before that: "Unless otherwise requested." Hopefully what units the answer should be in would be stated directly in the problem or on an answer sheet. If not, I'd recommend asking the proctor directly. If that doesn't work, I'd go ahead and just convert it to an SI or SI-derived unit (in the example you gave, you would convert the pressure in atmospheres to pascals (N/m^2)).

As for scientific notation, there doesn't seem to be anything in the rules addressing it, so you would only have to do it if explicitly instructed to do so on a test. There are a couple of cases, however, in which it would be a good idea to automatically put the answer in scientific notation even if not required to:
  • If giving a very large or very small numerical answer (Example: The initial pressure would be 15 atmospheres, or 1.5x10^6 pascals, rather than writing 1,500,000 pascals)
  • If you need to do so to express the correct number of sig figs (Example: if you need to write 300 with two significant figures, one typical way of doing this is instead writing it in scientific notation as 3.0 x10^2)

Re: Density Lab B

Posted: January 29th, 2019, 1:03 pm
by Srama
Much appreciate your response.

I specifically choose the above example, since the lowest sig fig is "1". That case, how do you express your final answer?


2. for density, answers could be in any metric units ? gm/cm3 ? or should it be in kg/m3

3. Pascal or Kilopascal should be good for pressure, right?

I understand "unless specified " clause.

Re: Density Lab B

Posted: January 29th, 2019, 2:45 pm
by John Richardsim
Srama wrote:Much appreciate your response.

I specifically choose the above example, since the lowest sig fig is "1". That case, how do you express your final answer?


2. for density, answers could be in any metric units ? gm/cm3 ? or should it be in kg/m3

3. Pascal or Kilopascal should be good for pressure, right?

I understand "unless specified " clause.
1. Oh, yeah, you're right. The answer will have only 1 sig fig. In this case, we will need use the rounding rules in the SO sig fig policy: https://www.soinc.org/sites/default/fil ... 2-5-12.pdf (SO's rules for rounding 5 either up or down are kinda weird).
So because the first nonsignificant digit is a 5, we need to round the number to the left to make it an even number. So 1.5x10^6 Pa ---> 2x10^6 Pa. (Again, since the rounding rules for 5 are strange, be aware that had the calculated answer been 2.5x10^6 Pa, it would also have rounded to 2x10^6 Pa.)

2. Yeah, I'd think they could be any metric units.

3. Both should be good.

Re: Density Lab B

Posted: January 29th, 2019, 2:55 pm
by Srama
Awesome!! Thanks a lot

Re: Density Lab B

Posted: February 11th, 2019, 1:00 pm
by RockRoll92
Alright, I may be doing this at states because no one else will. Is there anywhere in particular I should start? LIke looking things up or looking at practice tests and basing things off there? The rules are pretty vague, for density of solid, liquids, and gasses for example should we know the density of each material at room temperature?