Unit Quiz

The unit quiz was pretty easy compared to others. It had more questions than other quizzes but the concepts were more straightforward. The questions covered concepts from our lectures such as quantum numbers, electron configuration, and electromagnetic radiation. For me, I struggled a bit on naming the rules for electron configuration so I should focus some time on that.

Helpful Links
http://www.chem.wisc.edu/deptfiles/genchem/sstutorial/Text5/Tx54/tx54.html
https://www.khanacademy.org/science/chemistry/electronic-structure-of-atoms/electron-configurations-jay-sal/v/electron-configurations-2
http://chemwiki.ucdavis.edu/Core/Inorganic_Chemistry/Electronic_Structure_of_Atoms_and_Molecules/Electronic_Configurations

Flame Test Lab

In this first lab of our unit, we recorded the light given off by different metals when burning to determine the identity of an unknown atom. When atoms absorb energy, the electrons jump to a higher energy state and immediately fall back to ground state releasing that energy as light. Since each element has a unique arrangement of electrons, different colors will be emitted by each element. This lab was exciting with the bunsen burner but I was initially pretty confused with using the cobalt glass.

scholesscience.weebly.com
Barium

Electromagnetic Radiation

Recently, we learned about the wavelength, frequency, and energy of electromagnetic radiation. Wavelength is the distance from one crest to another on a wave while frequency is the number of cycles that pass through a point in one second. Energy is equal to the product of Planck's constant and frequency while frequency is the speed of light divided by wavelength. Converting between units such as nanometers and angstroms are also important for this unit since questions could be giving you different starting units.

Helpful Links
http://www.kentchemistry.com/links/AtomicStructure/waveequations.htm
http://chemwiki.ucdavis.edu/Core/Physical_Chemistry/Spectroscopy/Fundamentals/Electromagnetic_Radiation
http://www.chemteam.info/Electrons/calc-energy-freq-wavelength.html

Unknown Acid Lab

For the Unknown Acid lab, we basically performed the same procedure involving titrations from the Acetic Acid lab. The difference was that we had to determine the molar mass of the acids. We created our own procedure and used titrations to reach the molar mass. In the end, the acid ended up being the Asprin we made first semester.

Unit Exam

Before the unit test on Thursday, I was pretty anxious about the test because of many people saying it was hard. Despite this, I actually thought the exam was not extremely difficult although I struggled with a few questions. This will probably be one of the units I will have to review a lot for the final.

Helpful Links
https://www.khanacademy.org/science/chemistry/acid-base-equilibrium/titrations/v/titration-introduction
https://www.youtube.com/watch?v=XjFNmfLv9_Q

Titrations

Acid-Base titrations are used to find the amount of a known acidic or basic substance through reactions. The analyte is the solution with an unknown molarity while the reagent (titrant) is the solution with a known molarity that will react with the analyte. An indicator is used in titrations to determine when the endpoint is reached.

intranet.tdmu.edu.te.ua

Calculating pH

The measurement pH determines if an aqueous solution is acidic or basic. It can be calculated by with the concentration of hydronium ions in the solution. Another measurement is the pOH of a solution which can be calculated using the hydroxide concentration of the solution. Determining either value will let you get the other because pH and pOH add up to 14 at room temperature. Since weak acids and bases only partially dissociate in a solution, the equilibrium equation for the reaction will be used to determine how much they dissociate. 

Helpful Links:
https://www.chem.purdue.edu/gchelp/howtosolveit/Equilibrium/Calculating_pHandpOH.htm
http://www.chemteam.info/AcidBase/Ka-Solving1.html
http://www.chemguide.co.uk/physical/acidbaseeqia/acids.html
http://chemwiki.ucdavis.edu/Physical_Chemistry/Acids_and_Bases/Aqueous_Solutions/The_pH_Scale/Determining_and_Calculating_pH

www.sciencegeek.net

Acids and Bases

In Chemistry, Acids and Bases have many different properties. Acids feel sticky and taste sour while bases feel slippery and taste bitter. A Bronsted Lowry acid donates a proton while a Bronsted Lowry Base accepts a proton. Acids produce conjugate bases and bases produce conjugate acids in these reactions.

Acetic Acid Lab

Today we finished the first lab of this unit and it involved acid-base titrations. This is probably one of my favorite labs we have done because of the precise titrations. By using NaOH to titrate solutions of KHP and vinegar, we determined the % acetic acid in commercial vinegar with the data. The first day we performed practice titrations while we collected data on the second day. Fortunately by the end of the second day, my group got the hang of the titrations and our data was accurate.

buret used for titration

buret filled with NaOH 

container with KHP

indicator used for titration

end of titration