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### Re: Density Lab B

Posted: October 4th, 2018, 8:17 pm
Do any of you know if there are any practice tests for Density Lab?
syo_astro's SSSS test on the test exchange

(although there were rule changes between now and then)

### Re: Density Lab B

Posted: October 15th, 2018, 12:48 pm
Is this event math related?

### Re: Density Lab B

Posted: October 15th, 2018, 1:01 pm
Is this event math related?
Yes. Very. Although nothing complicated, more like multiplication and division.

### Re: Density Lab B

Posted: October 15th, 2018, 2:20 pm
Are there certain tools or materials I need to know how to use for this event?

### Re: Density Lab B

Posted: October 15th, 2018, 6:02 pm
Are there certain tools or materials I need to know how to use for this event?
Probably just know how to use a ruler or read a graduated cylinder.

### Re: Density Lab B

Posted: October 29th, 2018, 12:18 pm
Does anyone know what materials we need for the density lab?

### Re: Density Lab B

Posted: October 29th, 2018, 1:56 pm
Does anyone know what materials we need for the density lab?
A binder, writing materials, and calculators

### Re: Density Lab B

Posted: October 29th, 2018, 3:58 pm
What is 1 mol of gas at STP equal too?

The wiki says that its 22.71 L. https://scioly.org/wiki/index.php/Densi ... ro.27s_Law
Simply looking it up, says its 22.4 L.

Which do I believe?

Thanks,
Bob

### Re: Density Lab B

Posted: October 29th, 2018, 6:01 pm
What is 1 mol of gas at STP equal too?

The wiki says that its 22.71 L. https://scioly.org/wiki/index.php/Densi ... ro.27s_Law
Simply looking it up, says its 22.4 L.

Which do I believe?

Thanks,
Bob
22.4 L / mol is the value for an ideal gas (calculated from PV=nRT). A calculation that better approximates a real gas, such as the van der Waals equation, may have a different value - I suspect that's where 22.71 comes from. In general, I would recommend using 22.4 since it's more commonly cited. see the next post

### Re: Density Lab B

Posted: October 29th, 2018, 8:04 pm
What is 1 mol of gas at STP equal too?

The wiki says that its 22.71 L. https://scioly.org/wiki/index.php/Densi ... ro.27s_Law
Simply looking it up, says its 22.4 L.

Which do I believe?

Thanks,
Bob
22.4 L / mol is the value for an ideal gas (calculated from PV=nRT). A calculation that better approximates a real gas, such as the van der Waals equation, may have a different value - I suspect that's where 22.71 comes from. In general, I would recommend using 22.4 since it's more commonly cited.
The 22.71 L/mol uses 1 bar for STP (used by IUPAC since 1982), whereas 22.41 L/mol uses 1.01325 kPa for STP (used before 1982).

If in doubt, be sure to state the specific conditions for STP that you are using.