AP Chemistry 1.4 Forming and Breaking Bonds

AP Chemistry 1.4 Forming and Breaking Bonds. What is the correct expression for the equilibrium constant, Keq?

APAP Chemistry
AP ChemistryBreaking Bonds
Forming and Breaking Bonds
LanguageEnglish Language
Test PrepAP Chemistry

Transcript

00:28

And here are the potential answers:

00:31

Okay, okay, maybe we were a little hard on those Jacksons. This one really is as easy

00:37

as ABC… D. Can’t forget D. [Jackson 5 in chemistry class and teacher shows A, B, C, D on board]

00:41

Anyway, let’s get to our question. The equilibrium constant for any chemical

00:45

reaction will always be the concentrations of the products divided by the concentrations

00:48

of the reactants, with each species raised to the power of its stoichiometric

00:54

coefficient. Yeah, where's your ABC, 123 now, Jackson Five? [Person taking photo's of Jackson 5]

00:57

So for this reaction, the equilibrium constant is C times D squared divided by A squared

01:03

times B cubed. But wait, there’s more! Call now, and you’ll [Man selling frying pans]

01:07

get a second full set of banana-shaped frying pans for free, just pay $89.95 processing

01:12

and handling! …Whoops. Sorry for the confusion, that’s

01:14

our other job… tough economic times, right?

01:19

But there actually is more… There’s an important trick to this question:

01:22

we also need to consider the phase of each reactant and product.

01:27

Remember that we only include the reactants and products that are in the gaseous state [Reactants and product put inside a box]

01:31

in the equilibrium constant. We exclude species that are liquids or solids.

01:37

That means we can’t include species C in the equilibrium constant expression.

01:41

So, if we revisit our previous expression for Keq but remove species C, which is a liquid, [Species C removed from formula]

01:47

we’re left with D squared divided by A squared times B cubed. And that’s choice B, the

01:52

correct answer. Now, who wants some banana-shaped blueberry

01:56

pancakes? If we’ve learned one thing today, it’s that this is a deal too good to pass [Man selling banana-shaped blueberry pancakes]

02:00

up – don’t wait, call now! …Sorry. We have to meet a quota.