Mole Conversions --- By Tina Zhao

Mole Conversions

One- Step mole conversions

Conversions Particle/Atom/Formula Unit into Mole

Ex.1:How many moles of Carbon atoms are there in 3.01 X10^24C atoms?

             3.01 X 10^24   atoms 1 mol C/ 6.022ｘ10²³

Drawing and Interesting Graphs Using MS EXCEL --- by Ria Park

Since a graph represents the relationship between variables, sometimes a graph helps us to solve the density problem.

Density = Mass/Volume

Because a slope is equal to y/x(Rise-y over Run-x), the volume should be on x-axis. On the other hand, the mass should be on y-aixs.

We did the graphing with MS Excel. It was easy to make a graph and we can get the ideas easily.

Steps
- Open the MS Excel program and complete the table
- Click 'Insert', select 'scatter', then the graph will come out.
- Click anyone of the points and choose "Add Trendline" -> "Linear" or "Polinomial"
- Display Equation on the Chart
- Make it pretty!


And here are three graphs that we did in the class.

This is a video that demonstrates how to make a graph on excel.

http://www.youtube.com/watch?v=8B8kFVNzlQ8

Mole ----- By Sally Chen

Masses
Relative Mass:  expressed by comparing it mathematically to the mass of another object.
     - Hydrogen was used first as the standard; now Carbon is the standard (assigned to be 12).
Atomic Mass:  of 1 atom of the element
Formula Mass:  of all atoms in an ionic compound
Molecular Mass:  of all atoms in a covalent compound
Molar Mass:  mass of each mole of each element (in g/mol); formula/molecular mass of any pure substance.

WARNING:The following video contains an extremely annoying yet catching tune.
If you are allergic to such things, or do not wish to have a song stuck in your head, leave now.  :D

The Genius Avogadro:
Avogadro's Hypothesis:  equal volumes of different gases at the same temperature and pressure have the same number of particles.
Avogadro's Number:  6.022 x 10 to the 23rd (particles per mole)

Lab 2E -- By Nemo Jin

Determining Aluminum Foil Thickness

Formulas you might use

--V=L*W*H

   volume = length * width * height

--D=m/V

   density = mass / Volume

--Unknowns 

   volume;height

--Knowns

    mass;width;length;density

--Formula we are using 

    volume = mass / density

    height = volume / (length*width)

 Aluminum Foil

--Al

--92%~99%

--silvery white metallic element

--Density: 2.70g/cm*3 

Objectives

--to understand the key point of precision and accuracy 

--to calculate the thickness(height) of the aluminum foil

--to use absolute uncertainty in expressing your answers

Supplies

--3 pieces of aluminum foil

--metric ruler

--centigram balance

Procedure

--label three aluminum sheets 1,2 and 3

--use a metric ruler to measure the dimension of each aluminum foil

--measure the mass of each aluminum foil

--express your answer in scientific notation with proper significant numbers and absolute uncertainty

        length (cm)              width (cm)            mass (g)       Thickness(cm)

   1        16.80 ± 0.01                           15.31±0.01                      1.01±0.01              1.45*10^-3

   

   2        17.01±0.01                             15.60±0.01                      1.08±0.01              1.51*10^-3

   3        17.41±0.01                             14.59±0.01                      1.02±0.01              1.49*10^-3

Density --- By Tina Zhao

Density:
-The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ

Formula: 
-Mathematically, density is defined as mass divided by volume,Volume us defined as Mass divided by Density,and Mass is defined as Density multiply Volume:

   V=M/ ρ , M= ρ v

Ex1. An iron bar has a mass of 1200g with a volime of 1.25L,what is its density?

         we can use formula:  ρ=1200g/1.25=9.60g/l

Ex2. Neon is contained in a glass bulb having a volume of 22.4L. If the density of the neon is 0.900g/L, what is the mass of neon in the bulb?
     we can use formula: M=density x Volume, 0.900x 22.4=20.2g

Ex3. What is the volume of a tank that can hold 18 754 Kg of methanol whose density is 0.788g/cm³?
      if they have different Units, we should change Units first, and then calculate!!
    1.0.788g/cm³  became 0.000788kg/cm^{3
     2. we use: V=Mass/Density, 18754/0.000788=2380000000}cm<sup>3

 If you want to try more Density problem,the website is http://www.sciencebugz.com/chemistry/chprbdens.htm</sup> 

             Density of water = 1.0g/mL
             Dobject > Dliquid =sink
             Dobject < Dliquid =float