How to calculate Percent by Mass.

For this particular set of questions, you have to know what  solute and solvent are. Solute is the mixture or the thing that mixes. Solvent is the thing the solute mixed in. So let's say  I had sugar and water. Sugar would be the solute because it mixes it with the water (solvent).

Now that we have that cleared. we have to memorize a little thingy.

It is   mass of solute/mass of solution times 100.

Okay.
So they gave us a problem that looks like this:
What is the percent by mass of  CO2 in a solution containing 13 g  CO2 dissolved in 400 mL of water.

Look at the problem again. If you read this carefully you can see that dissolved is in bold. Now what dissolved in the water? The 13 grams of CO2!!!

That means the solute is 13 and the solvent is water.
Now we add the solute and the solvent.
13+ 400= 413g.

Now we know the mass of solution.
Look at the eqaution above.
mass of solute/mass of solution times 100.

Just plug in the numbers.
13/413 times 100= 3.14%

 So the answer for this equation is 3.14 %.

Any other questions, please comment!

How to find the Formula Unit.

Let's say some one asked,
 74.5 grams of H2O, please find the formula unit.

To find the formula unit first we sort of do the same thing like when we find the Molar Mass.
So Hydrogen has 2 atoms,  and Oxygen has 1 atom.
Multiply The hydrogen atom  with the atomic mass and  do the same thing for Oxygen.

You would have:
H: 2 x1.0079= 2.0158
O: 1 x16= 16

Now add them
You should have 18.0158.

Then get the 74.5 and divide it by  18.0158.
 The answer is 4.1325

Finally the last step is multiplying the answer by Avogadro's Number ( 6.02 x 10^23).

You should get

24.88 x 10^23 formula units H2O.

I think you can figure this out easily.

Hope this helps

Any other questions?

Any more questions you guys have or requests of explanations, Please comment below.
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Chemistry Cliffsnotes

I ordered a  book for chemistry and I am satisfied with it.
I saw some fellow classmates with it  as well.

http://www.amazon.com/CliffsNotes-Chemistry-Review-Edition-Cliffsquickreview/dp/0470905433/ref=sr_sp-atf_title_1_1?ie=UTF8&qid=1377739695&sr=8-1&keywords=chemistry+cliffsnotes

Hope this helps!

Conversion of Moles.

You would have to find the molar mass, then if the problem said,"What is grams?" Look at the equation, and if it says some thing like this
2.45 mol H2.
You would have to find the molar mass then,multiply the molar mass and 2.45 or whatever the number is. This is how you find the mass

The same goes if it asks for the mole.  you just need to find the molar mass and divide that by the number given. You would get the mole.

That is how you covert moles to grams and grams to moles.
As for volume and particles (atoms,etc.) There is an easy way.

Click here for the easy way.


Hope it helps!

Molar Mass

To find mass follow the steps:

You would first count the number of atoms given in the elements.

Example:
Cl_{3  would have 3 Chlorine atoms.} 

H2O   would have 2 hydrogen atoms and 1 oxygen. 


Then you would  multiply  the hydrogen atoms with the atomic mass. 

Example:
CL3: 3 CHLORINE ATOMS  times 35.453 ( CHLORINE'S ATOMIC MASS).

That is how you find  the Molar mass.

Electron Configuration Periodic Table

Found a Electron Configuration table. It is included with elements.

Hope this helps!