Electronegativity

Electronegativity is the measure of how much an atom "needs" electrons in
order to be in its most stable state. Generally, the if one removes the
nobel gasses from the periodic table (He, Ne, Ar, Kr, Xe, Rn), the most
electronegative elements are in the upper right hand corner of the periodic
table.  If one looks at water (H2O), oxygen is very close to the upper
right hand corner of the periodic table, where as hydrogen is not.
Therefore, oxygen "needs" the electrons more then hydrogen in order to be
stable and hogs the electrons. This makes the oxygen have a slightly more
negative charge, and the hydrogens slightly more positive.

Just for fun, Fluorine is the most electronegative, Francium is the least
electronegative and thus electropostive.

It is thought extreame differences in electronegativity give compounds
which are more likely to be ionic bonds. Atoms with electronegativities
closure to eachother are more likely to have covalent bonds. Polar
compounds have covalent bonds with one atom being slightly more negative
then the rest.

So you want to be a forensic scientist...Here is organic chemistry for you

For several reasons, I am going to make a new series on this blog called "So you want to be a forensic scientist...Here is organic chemistry for you" which is a rehash of my notes from Organic Chemistry in college.

I find that I have forgotten most of what I learned in college, and have been referring to old texts many times with my new progress so hopefully it will be mutually beneficial to both you and I.

Units, The Language of Forensics and Science

Whether you are doing a qualitative or quantitative experiment, you need to be able to express what you found.

Quantitative science is being able to say how much of something you found. For example, patient X had 15 ppm of cocaine in his blood stream.

Qualitative science is being able to say whether you found something or not. For example, patient X had cocaine in his system.

Why would you need units of measure to express the results of an qualitative experiment? Because you need to know if the result you found is above the minimum detection limit and thus is a usable finding. If your instrument cannot be reliable below 10ppm, then you cannot say for sure that a substance is present below that amount. You can say the test was inconclusive, or you can redo the experiential at a higher concentration if possible.

Being able to express amounts is very important, below I have made a chart that explains the different units and what they mean in relation to each other.

In my experience as a scientist, the people to know the differences between the units, can express them and calculate them are great scientists.

It will save you a lot of time and energy to print out these charts and quickly be able to do calculations back and forth. Then you will be a great, efficient scientist.

The #1 Math Equation you need to work as a Chemist

Back when I was doing job interviews, there were regular exams.

On every exam was a question that used this equation.

Every day in the lab, I use this concept and I call it my "Master Equation."

IV*IC=FV*FC

IV= Initial Volume

IC= Initial Concentration

FV= Final Volume

FC= Final Concentration

Some words of advice:

• IV and FV need to be in the same units, for example milliliters, cups, grams... ect.
• IC and FC also need to be in the same units, for example parts per million, micrograms per gram... ect.

A chemist uses this equation any time they make a solution.

As an example: I have a 100 parts per million solution and I want to make a 25 parts per million solution. In order to perform the experiment I need 10 milliliters of the 25 parts per million solution.

In this situation, you need to know how much of the 100 parts per million solution to dilute up to 10 milliliters to make a 25 parts per million solution.

Initial Volume= unknown (x)

Initial Concentration= 100 parts per million

Final Volume= 10 milliliters

Final Concentration= 25 parts per million

Your equation would look like:

x*100=25*10

multiplying everything gives:

100x=250

Then divide both sides by 100:

x=2.5

In order to make your 25 parts per million solution, you need to take 2.5 milliliters of the 100 parts per million solution and dilute it to 10  milliliters.

Learning how to apply this equation means that you can work in a wet lab with relative ease.

Wordless Wednesday

Wordless Wednesday

Another picture post.

Wordless Wednesday

Lots of dishes today.

Some fun retro decor.

Weighing in the demon scale :-)

Never forget the daily paperwork.

New Toy!!!