Oxidation Numbers of Ions & Ionic Compounds
Assigning oxidation numbers to ionic compounds is very similar to assigning oxidation numbers to covalent molecules, so if you haven't watched that video, watch it first.
Author Archives: hangtime
Oxidation Numbers of Covalent Molecules
Oxidation numbers are sort of like the charge on an ion, except for covalent compounds instead of ionic compounds. In this video I take you through the rules for assigning oxidation numbers, and I work lots of examples since this is definitely one of those topics where it's better to show examples than to talk about the theory too long.
What The Heck Is Redox
One of the hardest things about the redox chapter is that your teacher just jumps into talking about OIL RIG, oxidation, reduction, etc. without ever giving an overview of why the heck you're even talking about this stuff. So in this video I'll explain the "why" as well as the "what" of redox chapter problems that we'll cover in depth in later videos.
This chapter covers what redox and oxidation numbers are, and it shows you how to calculate the oxidation numbers for each atom on a compound. Also covered are oxidation numbers of monoatomic and polyatomic ions.
Do You Tweet?
Do you have friends who could use help?
(In math or science. Be nice.)
Now you can follow and tweet TTG the sassy way with the cool little twitter widget thingies on the left and right sides of the site! (see hi-fi diagram below):
Neutralization & Titration
In this video we'll do lots of different types of neutralization problems. How many moles of base are required to neutralize a given amount of acid? For volume-volume questions, we'll see how to use the MV=MV equation to figure out how many mL of base will neutralize a certain mL of acid. And we'll revisit our old friend STP to calculate how much acid-gas will neutralize base!
Neutralization refers to a reaction where acid and base cancel each other out, usually by forming water. Titration refers to performing a neutralization experiment in the laboratory under controlled conditions, and calculating stuff based on the outcome.
Ka and Kb: Weak Acid & Base Dissociation Constants
These are basically just equilibrium constants for the special case of weak acids and bases which don't dissociate fully (or much at all) in water. This video covers the use of ICE tables to solve the two major types of problems you might come across.
This chapter explains what is meant by a weak vs strong acid or base (it's not about concentration). It also explains how to use ICE tables to solve problems involving Ka and Kb.
Auto-Ionization: Why Is Water pH 7?
Pure water, strangely enough, always has some H+'s and OH-'s kicking around. Otherwise it wouldn't have a pH of 7. And a pOH of 7. But where did these H+'s and OH-'s come from, and where are they going? It's dynamic equilibrium, man.
Converting Between pH & pOH
It turns out that for any given solution (of stuff dissolved in water anyways), the pH and pOH have to add up to 14, no matter what kind of crazy acid or base you put in. I know I know I know, this is the kind of stuff that keeps you up at night pondering the complexities of the universe.
Converting pH & pOH to Molarity
In the previous video we saw how to calculate pH and pOH from concentration using a simple formula. In this video we'll do the opposite, turning pH and pOH into molarity. As usual we'll be doing it in style, using simple formulas rather than most teachers' preferred method, which usually involves rolling their eyes and expressing dismay that you don't remember your log rules from Algebra 2.
Calculating pH & pOH
In this video we'll use logs (logarithms) to calculate pH and pOH. Don't worry if you don't know your log rules: in this chapter, you won't stress your precalc beyond knowing how to find the log button on your calculator.
This chapter covers how to calculate pH and pOH from molarity, as well as how to calculate molarity from pH. Also covered is how to convert between pH and pOH, and why water auto-ionizes to pH 7.
Conjugate Acids & Bases
I hate to say it, but this chapter we're going 3-for-3 on videos that cover stuff you'll see on the chapter test and then never use again. In this particular installment, we'll learn how to identify and label conjugate acid-base pairs in a reaction.
Arrhenius vs Bronsted-Lowry vs Lewis
The three historical "definitions of acids and bases" which you'll probably have to know for your test. Spoiler alert: even after memorizing these, you're still going to be spotting acids and bases the same way you always have: H+ means acid, OH- means base (usually).
The Hydronium Ion
Honestly, when I was in school, my teacher never used the word "hydronium ion", so when I first heard a student tell me such a thing existed, I thought he was all wet. Turns out pretty much every book covers it, and my teacher was the exception. So here you go: the vocab word that launched the shortest video on the site!
Arrhenius vs Bronsted-Lowry vs Lewis definitions of acids & bases. The hydronium ion. Conjugate acid-base pairs.
Rate Laws
These are really similar to equilibrium constants and ICE tables, and that's a good thing. Once again, they're using the word "law" to refer to what everyone else would just call a formula. Stuff in brackets. A big table that will help you figure out the exponents for everything. And there won't even be any x's.
Reaction Rate Using Stoichiometry
Stoichiometry: is there anything it can't do? I know, you probably ask yourself that every day. Well, this video is only going to grow your already unfathomable appreciation for stoichiometry by showing that if you know the rate of change of creation/depletion of one compound in a reaction, you can figure out the rates for all the other compounds. I just blew your mind, right?