VIDEO: ACID-BASE EQUILIBRIUM

Students were shown this video in Friday's class.   Paul Andersen demonstrates the centrality of water to most acid-base chemistry, and explains how to calculate equilibrium constants for acids (Ka) and bases (Kb), and how to express those as pKa's or pKb's:

VIDEO: BALANCING EQUATIONS

In this VIDEO, Mr. Hatfield provides equations for reactions involving both ionic compounds and covalent compounds.

Then, step by step, Mr. Hatfield balances all of these equations.  

Balancing equations is an iterative procedure, sometimes called 'trial and error', and students have to practice the skill of unpacking and balancing equations many times before it will become routine:

 

VIDEO: ENTHALPY OF REACTIONS

The following video was shared in class on Thursday, Feb. 17th.   

This video builds on material introduced by your instructor, Mr. Hatfield, during lecture on Wednesday, Feb. 16th.

In the video, Paul Anderson helpfully reviews some of the information already given in lecture regarding heat and the enthalpy of reactions. It also features a very handy, step-by-step demonstration of how to apply Hess's Law (a SUBTLE and advanced topic) to calculate enthalpies.




Students have an Assignment based on that video, which is available HERE as a PDF file.  Copies of this Assignment were made available in class to complete in class that day.

VIDEO: FIREWORKS!

Students who were in Mr. Hatfield's classes on Tuesday, Oct. 5th, watched a PBS video entitled 'Fireworks!'  Students who need to watch it again, or who were not present on Tuesday, will find the video embedded below in this post.

The worksheet for this video can be obtained HERE.

Students should pay careful attention to TWO topics:

1) IONIC COMPOUNDS, which are described in Section 6.1 (pg. 158-163)

2)  ELECTRON CONFIGURATION (Section 4.4, pg. 124-127) 

VIDEO: THE FLAME TEST

If students were absent on Monday, Oct. 4th, they did not get to see the actual lab where we performed a 'flame test' on various ionic compounds.   

Here is a video that shows much the same sort of observations students made on Monday.   Unfortunately, it is not practical to 'make up' this particular lab. Watch the video, students, and compare it with observations that students who attended were able to make in order to understand the material:

VIDEO: THE BUNSEN BURNER

VERY IMPORTANT:  On Monday, Oct. 4th, all of Mr. Hatfield's classes will be doing an activity that involves gas.  Students are expected to know how to do this safely!

Mr. Hatfield has made a video to demonstrate the correct way to use the Bunsen burner.  Make sure you review this before you come to class on Monday, as we will be using the Bunsen burners in class to perform the 'Flame Test Lab'.

VIDEO: A QUICK LOOK AT THE PARTS OF THE ATOM

 This video from Pearson is intended to accompany Investigation 4 in our textbook:

VIDEO: DRAWING ATOMS, "HATFIELD STYLE"

In THIS video, Mr. Hatfield demonstrates his cartoony, unrealistic way of drawing atoms, where '+' are protons, '0' are neutrons and 'e-' are electrons.

Every attempt to draw an atom is, in some sense, unrealistic: after all, atoms are smaller than the waves of visible light which our eyes use to form images. In a sense, atoms don't look like ANYTHING.

Yet, while unrealistic, mastering the use of these symbols can help students develop a better understanding of atomic structure, which can be applied to ions and isotopes as well as neutral atoms.

VIDEO: EXPERIMENTAL DESIGN AND SIGNIFICANT FIGURES

Students:  here is a new VIDEO that introduces a concept that you must ALWAYS employ when performing calculations in Chemistry. 

Well-designed experiments take place in controlled conditions that account for variables, and which express their results in significant figures in order to handle the inevitable limitations to measurement that will occur.

When we do math in this course, we are NOT engaged in an abstract exercise in which the answer is simply a number for someone unknown variable, 'x'.  Instead, we are attempting to measure real phenomena and make predictions about what these phenomena will produce in the real world.

In that real world, there are limits to the ACCURACY and the PRECISION of our measurements.  Students must understand the difference between the related but distinct concepts!   Students must understand that the limits require us to not express our results with an UNREALISTIC level of precision, that was NOT actually observed!