IB SL Chemistry Unit 11 | Study Guide

University:
Kentucky State University
Course:
CHE 101 | General Chemistry I
Academic year:

2023
Views:

164

Pages:

3
Author:

Pompanin8za

UNIT ELEVEN ● Index of Hydrogen Deficiency ○ How many molecules of hydrogen is this compound away from being an alkane ○ IHD is measured as 2𝑥+2−𝑦 2 where you have the hydrocarbon CxHy. ● Infrared spectroscopy ○ Chemicals will vibrate under infrared light. This induces stretching in the molecule. ○ When given a graph, you should be able to identify the structure of the unknown compound. ○ Your data booklet will give you different regions and signs to look for in order to identify the compound. In this case, we see a spike around 3000. This can mean hydrogen bonding, an alcohol group, or an amine group. Mass Spectroscopy ○ You create ions of elements by ripping off electrons. That way you get fragments of the compound to come off. You will create two ions. One that’s detected by mass spec, and the other ion is defective. ○ Your data booklet will give you the estimated mass of these fragments. For practice problems, you can find a chart online. ○ In this we see a fragment at 15 % abundance. This is most likely a CH3+ ion. ○ We see another spike at 43, which is a COOH+ group. ○ This means that the unknown compound is CH3COOH, or ethanoic acid. ● H NMR: ○ Judges the shift of electron in comparison to Tetramethylsilane ○ Different shifts will have values assigned to groups. These major groups will be in your data book. ○ We see a peak at 10 and a peak at 2 parts per million. 10 is an aldehyde, and 2 is a methyl group. That means this is a CH3CO, or ethanal. General Tips ○ Don't procrastinate. I know this is a super common piece of advice, but especially in a class like this, if you have anything you don't know, you need to learn it asap. Attempting to cram a unit the night before the test will only fail you. ○ Use Other resources. There is always much more to learn. I will do my best to explain every topic, but if I ever miss anything or describe something inadequately, use other sources. I highly recommend Richard Thornley, Khan Academy, Organic Chemistry Tutor, and Andrew Weng. ○ Practice, Practice, Practice. What I have here will be a few worked example problems, but you won’t ever properly learn these until you take it upon yourself to find worksheets that provide lots more practice problems. ○ Make sure you know IB’s specific examples. Throughout the study guide, you’ll see me talk about super niche examples of a lesson. Those are recurring themes on IB tests that you must know. ○ This study guide assumes that you have taken a prior chemistry class. ○ All IB courses are taught differently. This study guide will focus more on chemistry, rather than connections to TOK or Cas.