Molar Volume Lab

Hello again!
We did a Molar Volume Lab before the Winter Break and it contained a sink full of water, a graduated cyliner, and a lighter with a substance called Butane which is known for its combustive traits. But in this lab we measured how much Butane is consumed  underwater on top of a graduated cylinder. This sets us up with our estimated "STP" or Standard Temperature and Pressure, which is 22.4. None of our classmates were near to the number but one of the groups recorded a 24.2, which was SATP.

Multi-Step Conversions

  Sometimes, there will be cases where you will be given information that you would have to use in order to make numerous conversions. Here are some examples:

EXAMPLE:

12.5 grams of Hydrogen (H2) are placed in a balloon at STP (Standard Temperature and Pressure = 0º C & 101.3 kPa). Determine it's volume.

1. First, use molar mass as your conversion factor and cancel accordingly.

-> 12.5 g of H2    x    1 mol     
                               2.0 g*


*The mass in grams is 2.0 because there are hydrogen is diatomic.

2. Next, use molar volume as your conversion factor and cancel accordingly.

-> 12.5 g of H2    x    1 mol    x    22.4 L
                               2.0 g           1 mol

3. Alter your answer to have the appropriate number of significant digits.

-> There are 1.4 x 10² Liters in 12.5 grams of Hydrogen.


   There will be other instances where they ask you for more conversions such as grams to atoms or liters to molecules. The most important thing to do is to first recognize what you have and what your answer's units should be. From there, you can decide on you conversion factors. Here are some of them:

Molar Volume (of all gases @ STP):
22.4 L / 1 mol

Molar Volume (of all gases @ SATP-> Standard Ambient Temperature & Pressure):
24.8 L / 1 mol


Molar Mass:
grams (g) / 1 mol


Avogadro's Number:

6.02 x 10²³ molecules or atoms or fundamental units / 1 mol

  Here are some links to help you out as well:
http://www.youtube.com/watch?v=tS9l-OxucQU
http://www.youtube.com/watch?v=AsqEkF7hcII&feature=related
http://www.youtube.com/watch?v=8TkY36qB1f0

Moles to Molecules

Remember Avogardo's number?

6.02 x 10^23

Well in this lesson we learned about how to convert Moles into Molecules

We did examples like:
-How many atoms are there in 1.5 mol of Iron?

We start off like this

1.5mol x __________

Since we have to cancel out moles, to cross multiply out the mols, you have to put 1 mol (usually) on the bottom

1.5mol x __________
                  1 mol

And remember Avogardo's number? Well plug it in the top!

1.5mol x 6.02 x 10^23 molecules
                         1 mol

So since the moles cancel out, we multiply 1.5 mol and Avogardo's number and we get....

1.5mol x 6.02 x 10^23 molecules = 9.0 x 10^23

                         1 mol

Well thats all for today guys!