November 23 Greg Sra

Today we learned about harder mole conversions. First off you have to start with a mole map.

GRAMS --> <--Use Molar Mass <----> Moles --> <--Avogadro's Number --> Molecules
(6.022 * 10^23)
So if you want to go from Molecules to moles you would divide by 6.022 * 10^23. Grams to moles you multiply by 1mol/Molar Mass in Grams

Random Joke of the Day. How much does Avagadro exaggerate? He makes mountains out of mole hills.
http://misterguch.brinkster.net/molecalculations.html
A website to help you with mole conversions!

 

NOVEMBER 17- MARCCCUS LU

MOLES

CHAPTER 4 ---- THE MOLE

Molar Mass is a unit of measurement.  A mole is anything that has the same particle number as 12.00 grams of carbon.  The number of particles is Avogardo's number :  6.02 X 10^23.

TO find the molar mass of a substance, you use a periodic table to find the atomic mass underneath the name of the substance, and write it in grams per mole

EX:  1 mole of oxygen = 16.0 grams per mole

 1 mole of potassium= 39.1 grams/ mole

REMEMBER: The number of particles in 1 mole of any substance is 6.022 X 10^23 particles/mol

November 19th -Nick kim

Mole conversion  

A

-converting atoms,particles,molecules,and formula units into moles(6.022x 10²³)

#  6.022x 10²³ particles,atoms,molecules,and formula units = 1 mole

Ex 4.56x 10⁴³ baron particles into moles

4.56x 10⁴³ particles x 1mole/6.022x 10²³ particles

4.56x 10⁴³/6.022x 10²³ =0.757x 10

                                                  = 7.57x 10²¹

B

-converting moles into grams                                

# In each elements in periodic table, they all have atomic mass

Eg. Fluorine=19.0 Chlorine=35.5 .........
units are g/mol, it means there are 6.022x 10²³ (mol) atoms for one element and they are measure in gram. Therefore, Fluorine has mass of 19.0g/mol 

Ex, 4.01 moles sillicon(28.1g/mol) into grams
4.01moles x 28.1g/mole
4.01 x 28.1=113 g

here is website that will help

http://www.youtube.com/watch?v=ehepBBtSbDc

http://www.youtube.com/watch?v=NMdN1LtHuDA

November 9th Greg Sra

Last class we created a graph about a sample of gas heated in a expandable container. We also got back our quiz's, and have a test next class for Chapter 3.

Chapter 3 Test
On it will be: Sig Figs, Measurement & Uncertainty, Density, Graphing, and Lab 2e.

Random Chemistry Joke of the Day:  A neutron walks into a bar. He asks for a beer. The bartender looks at him ,and says for you No Charge.

Friday November 5 ---- Marcus Lu

Wrote quiz today on aluminum foil lab.  It is required for you to know the Density formuila ( density = mass/volume)  and Volume = L x W x H.

We learned how to make graphs on microsoft excel to express our data.

November 4-NIck kim

 For today, we did our lab on determining aluminum foil's thickness. It was easy and fun lab, we ever had. In order to find thinkness(height) first we needed to know it's length,width,and weight, since aluminum foil is really thin it hard to measure without specalized tool, so we need to use math to find it

when we found out the length,width, and weight. we need to put them in to equation.(density is given)

Formula

 Density(cm3/g)=Gram(g)/volume(cm3)

#volume is equal to (length)(width)(height)

and let height represent x

For example, length:16.80cm width:14.85cm height:x density:2.70g/cm3 gram:1.00

2.70cm3/g=1.00g/(16.80cm)(14.85cm)x
2.70cm3/g=1.00g/249.48x
1.00g/2.70cm3/g(249.48cm2)=x(thinkness)
therefore   x=0.0015cm

In this lab we have practiced how to use density formula

Here is website that help how to get thickness of aluminum foil
http://www.mefeedia.com/watch/29045208

November 2 -- Ahmad Kilani

So last day we were introduced to a new unit; DENSITY:

So density is basically a unit of calculating mass per volume such as g/L (grams per liter) or pounds/cm3... here's a sample of densities:

From small to big.

So basically, the less dense an object is, then that means it floats on a denser object. Here's a video to demonstrate that: