Dimensional Analysis

Today in Chemistry we went over using Dimensional Analysis. Its basically a fancy word for problem solving and converting units. This was basically a review of math but using formulas we just learned and putting them to work. These formulas made converting much more easier.

Converting is easy as:
1. Identifying what units you to end up with
2. Find the Conversion Factors
3. Place units in the appropriate place
4. Cancel units

e.g.
How many miles are equal to 120 km?

Powers of Ten

Todays class Mr. Doktor started by telling the class about some really interesting news about: Scientist breaking the speed of light in Genova, a finding that could overturn one of Einstein's fundamental laws of the universe. Measurements taken over three years showed neutrinos pumped from CERN near Geneva to Gran Sasso in Italy had arrived 60 nanoseconds quicker than light would have done.



We then had a lesson on Significant Digits & Scientific Notation, and Mr. Doktor gave us a worksheet to practice and review.
- All #'s from 1-9 are significant
- When we add/subtract two #'s we determine the number of significant digits by lining up the numbers and then rounding the decimal.
- When we multiply/divide two #'s we determine the # of significant digits by rounding to the #.

Coverting/Expanding
250,000,000 = 2.5x10^8
2.57x10^4 = 257,000

SI Units and Error in Physics!

Today Mr. Doktor introduced us SI units and it's prefixes. The SI prefixes indicate how much multiplier (by 10) a unit is measured. For Example: a unit of 1000 can be indicated as 10^3 or in other words "a kilo". These prefixes can be find anywhere from computers to cameras and to any measuring device (Terabyte, kilogram, megapixel, etc.).
These are some of the prefixes in SI Units (and its multipliers):





Error is an unescapable part of science. Measuring instruments are never completely free of flaws and measuring always involves estimation. Three reasons error might ovvur in an experiment could be: The measuring instrument has a flaw, estimates of the human maybe wrong, or chaning ambient conditions of the surroundings may change.
We also learned about Absolute Error and Percent Error. Absolute error and percent error are used to determine how precise and accurate something is.
The formula for Absolute Error is:
Absoulte Error = Measured Value - Accepted Value
The formula for Percent Error is:
Percent Error = [(Measured Value - Accepted Value) / Accepted Value] x 100

Homogeneous and Heterogeneous Substances!

In today’s class, Mr. Dockor had briefly gone over a few of the balancing word equations from our homework that’s due next class. After that we had moved on to how we name matter helps us understand it. We learnt that matter can be divided into 2 types, Homogeneous Substances and Heterogeneous Substances. The two types of matter can also be broken further down into smaller groups such as pure substances, elements, compounds, mixtures, solutions and such displayed in the diagram below. Near the end of the class we also saw an example of how a mixture can be separated.

Homogeneous: consists of only one visible component (eg. distilled water, oxygen, graphite)

Heterogeneous: contains more than one visible component (chocolate chip cookie, granite)

2 types of pure substances:

Elements- substances that can’t be broken down into simpler substances by chemical reactions (any element)

Compounds- 2 or more elements that can be changed into other compounds by chemical reactions. (Water, sugar)

Solution- a homogeneous mixture of 2 or more substances (Fog, Steel)
-the component present is greater amounts is the solvent and in smaller amounts is the solute.

Mixtures- heterogeneous mixtures have different parts to it that is clearly visible (blood, sand)
- 5 different ways to separate mixtures
- by hand
- filtration
- distillation
- crystallization
- chromatography

Physical and Chemical Change:

In today's class we looked over the homework we did last class which was all about balancing. In most cases, the balancing equations part was easy for me but on occasion there were these weird numbers which we had to make into a fraction then do all the math but all in all, it was actually fun for me.

Then we reviewed something we had all learned last year, the changes in matter such as physical and chemical change. One thing i didn't know that was also part of change was nuclear change. Its interest how this all works, you either added energy or removed energy to undergo change.
The three groups are broken down into these:

-Physical Change is just a changing in shape or state of matter
e.g.

-Chemical Change is making new substances or the properties of the matter change
e.g.

-Nuclear Change is a fusion of neutrons and protons or a change of nuclear structure such as fission of a nucleus atom.
e.g.

Balancing Equations!

Todays class we went over our homework, which was a small review of the Lab Safety Rules. Each student then received a green, yellow, and red card to let Mr. Doktor know if we were understanding what he was teaching throughout the lesson. (Green as in I fully understand, Yellow as in I need a few more examples, & Red as in I don't get it at all.)

First we learned what aqueous was (A solution dissolved in liquid) and some other few phase symbols. Ex: Al (s), H2O (l), AgNO3 (aq)

He then listed and explained the Diatomic Molecules: H2, N2, O2, F2, Cl2, Br2, I2
& Polyatomic (many) Molecules: P4, S8

Then Mr. D went through the colummns of the Periodic Table, & explained to us the noble gases, non-metals, and metals. We then took notes on Balancing & Word Equations & were taught an easier way to balance equations without drawing a chart.

An example would be balancing Double Replacement:
2AlCl3 + 3CO2 + 3H2O ---> Al2(CO3)3 + 6HCl


Video taken from kahnacademy.com.

Lab Prep! Rules and Safety in the Laboratory 101

Today for class, Mr Doktor explained to us various Safety procedures when doing an experiment in the laboratory. He made us get into groups and create our own "Top 10 Safety Rules" to help create an official safety list for the class. During the class he also showed us a video which enlightened us how not applying safety precautions during experiments can lead to dangerous or even deadly consequences. So overall, in today's class we learned that we should learn the proper safety precautions in a lab to ensure our safety and others as well.

An example of a Top 10 Science Safety that was made:
1. Wear lab coats and safety goggles
2. No horseplay (running)
3. No touching, tasting, directly smelling chemicals
4. Listen to everything Mr. Doktor says
6. No eating during lab experiments
7. Raad labels before using chemicals
8. Don't leave an experiment unattended (especially Bunsen Burners)
9. Use the appropriate procedures in an emergency
10. Alert Mr. Doktor if anyone is hurt or if something breaks

Welcome to our Chemistry 11 Blog 2011-2012!

Bloggers: Aldin Agustin, Christian Arenzana, Kimberley Matibag, Suban Selvakumaran
Course: Chemistry 11
Teacher: Mr. Doktor
Block: C



CHEMISTRY 11 LEGGO!