Basic Review of Chemistry

This week was focused on reviewing chemistry, which proved to be more challenging than I expected! We learned about the pH scale, acids, bases, buffers, and started to look at macromolecules as well. After the chapter review last weekend, I caught up on some key concepts that I previously learned in chemistry.

First, pH is the measure of hydrogen ion concentration in a solution, and looks like this:-log[1 X 10^7]. This represents a 7 on the pH scale, meaning neutral, whereas a log[1X10^3] is more acidic. The more acidic the solution, the more hydrogen ion concentration there is. The more basic the solution, there is less hydrogen ion and more OH- particles. A buffer is something that tries to resist any change in pH. It brings the acidic substance or basic substance more towards neutral. Between each pH unit, there is a 10 fold increase or decrease in H+ (depending on whether it is basic or acidic.) Also, when the pH goes up or down .3 units, there is a 2X increase/decrease of H+.

ALSO: conjugate base is what is left after an acid has donated a proton in a chemical reaction.

We also reviewed other things like subatomic particles, valence electrons, electronegativity, ions etc. The order of bonds strongest to weakest are:

  1. Covalent bonds
  2. ionic bonds
  3. hydrogen bonds
  4. Van der Waals interactions
An Ionic bond: the loss or gain of an electron from one atom to another
A covalent bond: The sharing of electrons
Hydrogen bond: Positive connects to negative side 

Lastly, we learned about macromolecules, which is probably the most confusing thing we did this week. Macromolecules make up everything in this world, and the most common elements are CHONPS: carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur. In the macromolecule packet, I got confused how each molecule is different compared to each other and also how bonds had to be structured a certain way. I think I need to review valence electrons a little more to understand how molecules connect in different ways. Also, why are certain molecules structured the way they are? Why are they put into different groups like fats or lipids? What defines these groups?

We also checked on our plants throughout the week, and my group’s plant (tommy) is slowly dying which is unfortunate. I don’t think we pollinated it well enough and one of the plants necks snapped off :.(


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