Thursday, September 30, 2010

Laboratory Report

Last class we did a lab on physical and chemical changes:
Lab 2C: Physical and Chemical Changes 

Laboratory Report Format:

1. Cover Sheet
  • name, date, block, name of partner in top right corner
  • title of lab in center of page
  • brief abstract underneath table
      Abstract: the purpose of the abstract is to inform the reader in as few words as possible what was gained from the experiment. It should include a brief (i.e. one or two sentences) outline of the procedure and results. This section should be written in the second person in the passive voice and in the past tense, since it is written after the rest of the lab report has been completed.

2. Report Write-up

Purpose: Write a statement that indicates what you want to find out by doing the lab.

Materials and Equipment:    i.) Write "Refer to page ## in Heath Lab Text, Lab ##"
                                     ii.)  List any change to the above procedure in point form.

Procedure:            i.) Write "Refer to page ## in Heath Lab Text, Lab ##"
                            ii.)  List any change to the above procedure in point form.

Sample Calculations: If required, do any calculations required to complete the data table. For labs with many similar calculations, include only one sample calculation for each type of calculation involved. These are calculations for the data table only, not for discussion section.

Discussion: Complete all questions assigned. Use full sentences for your answers. Show all calculations for quantitative questions.

Sources of Error: Write a list of factors that could have affected your final results. With each point you mention, indicate how it would have affected the results.

                           For example: There was an air bubble in the buret that came out while titrating. 
                           This will give a higher recorded volume of NaOH used than actually needed resulting in an 
                           apparent higher molarity of HCl.

Conclusion: Include a brief formal statement, which lists your result(s) and/or what you have learned in the lab.


-Lauren

Monday, September 27, 2010

Matter

What is matter ?
- Matter is anything that has mass and volume. Therefore, you are also considered as matter :)
- It always appears to be a solid, liquid or gas
- Can change physically or chemically
- 2 types : Pure substance and mixture
- Element can be classified as metal, metalloid or non-metal
- Compound can be either an ionic or covalent bond
For those who dont't know what homogeneous and heterogeneous mean:
- Homogenous:  consisting of  one visible component
- Hetergeneous : consisting of  2 or more visible components

Physical change and Chemical change
    It's easy to tell the difference between physical change and chemical change. Physical change is reversible, meaning that you can always change the substance's form back and forth easily, while chemical change is irreversible. No new substance is formed during a physical change, but for chemical change, there is. For example, if you burnt a bacon when you're cooking, you get all those black areas on the meet. That is a chemical change.


Change of State

 
Solid → The particles are tied close together. Does not change shape and volume easily.
Liquid → Between solid and gas. Catalyst like heat is able to make slight changes in shape and volume 
Gas → The particles are widely spread out. Volume and shape can be changed drastically.


- By Catherine:)

Friday, September 24, 2010

QUIZ NEXT CLASS!

Last day, the class went over the latest worksheets, and had a practice quiz.
Next class, Monday the 27th, there will be a QUIZ on Unit Converions and Scientific Notation!
GOOD LUCK!

Wednesday, September 22, 2010

Scientific Notation and Even More Unitary Rates

Scientific Notation


  •  A way scientists handle very large and very small numbers using powers of 10.

  •  Written in the form a x 10^b
Examples:
Write in Scientific Notation
a)      4830000000  à4.83 x 10^9
b)      0. 000056 à 5.6 x 10^-5


Write in Standard Form:
a)      6.25 x 10^4 à 62500
b)      8.9  x 10 ^-9 à 0.0000000089

-         Addition and Subtraction
o       All numbers must be converted to the same power of 10
o       The digits are then added or subtracted
-         Multiplying and Dividing
o       Digits are multiplied or divided
o       Exponents are added or subtracted.
* Keep exponent laws in mind*


Quiz Yourself!!
Here is a great website to practice multiplying, adding, subtracting and expressing numbers in scientific notation:



*Note* Calculators can be used to make this process easier. Use the EXP/ E / x 10^ buttons.

Even More Unitary Rates

-         Convert the unit which is squared or cubed
If 1m= 100cm
1m^2 = 10 000 cm^2  (100 x 100)
1m^3 = 1 000 000 cm^3  (100 x 100 x 100)

Ex. Convert

a)      9.6m^3 à to km^3
1000m= km
10^9 m^3 = km^3

9.6 m^3 x (km^3/10^9 m^3)
= 9.6 x 10^-9 km^3

b)      6.5 dm^2 à Gm^2
dm à mà Gm

10^2 dm^2 = 1m^2                (10 dm = 1m à 10^2dm = 10m^2)
10^18 m^2 = 1 Gm^2            ( 10^9m = 1Gm à 10^18 m^2 = 1Gm)
= 6.5 x 10^-20 Gm^2

Here are some examples to try on your own:

a)      Convert 7.5 dm^2 to Mm^2
b)      Convert 54 mm to pm
c)      Convert 5.5 m^3 to km^3
d)      Convert 12.4 L to mL


By Candace

Monday, September 20, 2010

Group data


Hi ! I'm Dmitri Mendeleev!
I'm back to life! Now I'll be teaching Chemistry online! Cool, isn't it?

Group members:
Lauren Yeung, Victoria Matsushita, Candace Gordon, Catherine Law
Block : 2-2
Teacher: Ms. Chen
Subject: Chemistry 11