Week 5: Ketones and Aldehydes - Workbook (Monash S2 2024) PDF

8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 Week 5: Ketones and aldehydes - workbook Site: Monash Moodle1 Printed by: Kaltham Alzaabi...

8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 Week 5: Ketones and aldehydes - workbook Site: Monash Moodle1 Printed by: Kaltham Alzaabi Unit: CHM1022 - Chemistry II - S2 2024 Date: Sunday, 18 August 2024, 2:44 PM Book: Week 5: Ketones and aldehydes - workbook https://learning.monash.edu/mod/book/tool/print/index.php?id=2780423 1/13 8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 Table of contents 1. Pre-workshop material 1.1. Carbonyl groups 1.2. Hybridisation and electronegativity 1.3. Synthesis of alcohols 1.4. Oxidation of alcohols 2. Summary 3. Preparation quiz 4. Online lectures https://learning.monash.edu/mod/book/tool/print/index.php?id=2780423 2/13 8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 1. Pre-workshop material The Carbonyl Group In week 1, we introduced you to common functional groups. Many functional groups contain a carbonyl group. A carbonyl is a double bond between an sp2 carbon and an sp2 oxygen It is made of a σ-bond (between sp2 orbitals) and a π-bond (between p orbitals). It is polarised due to the difference in electronegativity between carbon and oxygen (more details to follow). This week we will be focusing on two carbonyl containing classes of compounds, aldehydes and ketones (see Figure 1 for their general structures). Figure 1: Compounds containing the carbonyl functional group. Please read Sections 19.1, 21.1-21.4 of Chemistry, Blackman et al. (4th ed.) Please read Chemistry: Atoms First (2019), Chapter 21.3 https://learning.monash.edu/mod/book/tool/print/index.php?id=2780423 3/13 8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 1.1. Carbonyl groups Aldehydes and ketones The aldehyde functional group consists of a carbonyl centre with a hydrogen and a hydrocarbon group (alkyl) attached (Figure 2). Figure 2: Structures of various aldehydes. A ketone functional group consists of a carbonyl centre with two hydrocarbon groups (alkyl) attached (Figure 3). Figure 3: Structures of various ketones. MolView Shown below are the molview files of acetaldehyde and butanone. Spend a bit of time rotating both molecules. Notice the trigonal planar geometry (bond angle of 120°) of the carbon in the carbonyl group. Click here for more information on how to use MolView. https://learning.monash.edu/mod/book/tool/print/index.php?id=2780423 4/13 8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 Acetaldehyde Butan-2-one Interactive Acetaldehyde Molecule (Source: http://molview.org/? Interactive Butan-2-oneMolecule (Source: http://molview.org/? cid=177) cid=6569) https://learning.monash.edu/mod/book/tool/print/index.php?id=2780423 5/13 8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 1.2. Hybridisation and electronegativity Hybridisation The hybridisation of the carbonyl group can be seen as an extension of that observed in ethene; both the carbon and the oxygen atoms of the carbonyl atom are sp2 hybridised. The electrons of the carbon atom rearrange themselves to give three sp2 hybrid orbitals that are 120° to each other. The remaining p-orbital is at right angles to the hybrid orbitals. For oxygen, the same process occurs and in this case two of the sp2 hybrid orbitals contain lone pairs of electrons. The carbon atom and the oxygen atom then bond much like in the example of ethene, with end-to-end overlap of the atomic orbitals that are pointing towards one another (Figure 5) to produce a σ-bond. This leaves the p-orbitals to overlap sideways producing a π-bond. Figure 5: Orbital hybridisation of the carbonyl group in formaldehyde Electronegativity Electronegativity is a measure of the tendency of an atom to attract electrons. The Pauling scale is most commonly used for this purpose. The value of carbon is 2.5 and oxygen is 3.5. Hence, oxygen is more electronegative than carbon. The difference in polarity is large enough to make the C=O bond polar. You can also consider the carbonyl as mix of the two resonance structures shown (Figure 6). The oxygen atom has a slight negative charge (δ-) and the carbon has a slight positive charge (δ+). Consequently, nucleophiles can attack the electron poor δ+ carbon atom and electrophiles can attack the electron-rich δ- oxygen atom. Figure 6: Polarity and resonance of the carbonyl group https://learning.monash.edu/mod/book/tool/print/index.php?id=2780423 6/13 8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 1.3. Synthesis of alcohols Please read Section 19.2 of Chemistry, Blackman et al. (4th ed.) Please read Chemistry: Atoms First (2019), Chapter 21.3 Synthesis of alcohols The hydration of alkenes is a common way to make alcohols from alkenes. This addition reaction, and its mechanism were introduced in week 1 (Figure 7). The hydration reaction follows the same rules (Markovnikov, for example) as the addition of H-X to an alkene. Figure 7: Hydration of alkenes. https://learning.monash.edu/mod/book/tool/print/index.php?id=2780423 7/13 8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 1.4. Oxidation of alcohols Oxidation of alcohols Alcohols (-OH functional group) are classified as being either a primary, secondary or tertiary alcohol according to the number of carbons that are attached to the carbon bearing the alcohol. One is primary, two is secondary, three is tertiary. Oxidation of different types of alcohols produces different products (Figure 8). Primary alcohols have two C-H bonds. They are oxidised first to the aldehyde. The aldehyde has a remaining C-H bond and can be further oxidised to the carboxylic acid. Secondary alcohols have one C-H bond. They are oxidised to the ketone. Tertiary alcohols have no C-H bonds, and can not be oxidised to a carbonyl compound. Figure 8: Oxidation of different alcohols to aldehydes, ketones and carboxylic acids https://learning.monash.edu/mod/book/tool/print/index.php?id=2780423 8/13 8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 2. Summary This week we have learnt about ketones and aldehydes their importance in organic chemistry and also the world around us. A key focus of this week has been on understanding the structure and electronics of these molecules. Explore the 3D representation for the nucleophilic addition to a carbonyl group illustrated in this ChemTube 3D page (click the link). Use the controls located at the right hand corner of the image of the molecule to rotate it. Click on each of the molecular structures/reaction arrows to load the corresponding 3D representations, and see the animations. https://learning.monash.edu/mod/book/tool/print/index.php?id=2780423 9/13 8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 3. Preparation quiz Now that you have completed the pre-workshop material, attempt the following preparation quiz. These 10 questions give you a chance to test your knowledge and practice the skills that were covered in this week's pre-workshop material. This material is essential for this week's workshops and may be applied in your laboratory classes. You have two attempts at each quiz and your highest attempt will count towards your final grade. Preparation quiz for Week 5 https://learning.monash.edu/mod/book/tool/print/index.php?id=2780423 10/13 8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 4. Online lectures CHM1022 Weeks have These captions 5 andbeen 6 welcome video automatically generated. As such, the CHM1022 Weeks 5 and 6 welcome video quality is not 100% accurate. Accuracy may be affected by audio quality, topic under discussion and clarity of the speakers. Staff are not expected or required to edit or correct automatically- generated captions. It is best to not rely solely on captions when viewing video play_arrow content and to use them alongside other learning resources. Students who are registered with Disability Support Services should be in contact with them to discuss captioning if needed. Powered by Panopto get_app closed_caption fullscreen keyboard_arrow_up Week5-L1-part1 These captions have been automatically generated. As such, the Week5-L1-part1 quality is not 100% accurate. Accuracy may be affected by audio quality, topic under discussion and clarity of the speakers. Staff are not expected or required to edit or correct automatically- generated captions. It is best to not rely solely on captions when viewing video play_arrow content and to use them alongside other learning resources. Students who are registered with Disability Support Services should be in contact with them to discuss captioning if needed. Powered by Panopto get_app closed_caption fullscreen keyboard_arrow_up Week5-L1-part2 These captions have been automatically generated. As such, the Week5-L1-part2 quality is not 100% accurate. Accuracy may be affected by audio quality, topic under discussion and clarity of the speakers. Staff are not expected or required to edit or correct automatically- generated captions. It is best to not rely solely on captions when viewing video play_arrow content and to use them alongside other learning resources. Students who are registered with Disability Support Services should be in contact with them to discuss captioning if needed. Powered by Panopto get_app closed_caption fullscreen keyboard_arrow_up Week5-L1-part3 These captions have been automatically generated. As such, the Week5-L1-part3 quality is not 100% accurate. Accuracy may be affected by audio quality, topic under discussion and clarity of the speakers. Staff are not expected or required to edit or correct automatically- generated captions. It is best to not rely solely on captions when viewing video play_arrow content and to use them alongside other learning resources. Students who are registered with Disability Support Services should be in contact with them to discuss captioning if needed. Powered by Panopto get_app closed_caption fullscreen keyboard_arrow_up https://learning.monash.edu/mod/book/tool/print/index.php?id=2780423 11/13 8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 Week5-L1-part4 These captions have been automatically generated. As such, the Week5-L1-part4 quality is not 100% accurate. Accuracy may be affected by audio quality, topic under discussion and clarity of the speakers. Staff are not expected or required to edit or correct automatically- generated captions. It is best to not rely solely on captions when viewing video play_arrow content and to use them alongside other learning resources. Students who are registered with Disability Support Services should be in contact with them to discuss captioning if needed. Powered by Panopto get_app closed_caption fullscreen keyboard_arrow_up Week5-L1-part5 These captions have been automatically generated. As such, the Week5-L1-part5 quality is not 100% accurate. Accuracy may be affected by audio quality, topic under discussion and clarity of the speakers. Staff are not expected or required to edit or correct automatically- generated captions. It is best to not rely solely on captions when viewing video play_arrow content and to use them alongside other learning resources. Students who are registered with Disability Support Services should be in contact with them to discuss captioning if needed. Powered by Panopto get_app closed_caption fullscreen keyboard_arrow_up Week5-L1-part6 These captions have been automatically generated. As such, the Week5-L1-part6 quality is not 100% accurate. Accuracy may be affected by audio quality, topic under discussion and clarity of the speakers. Staff are not expected or required to edit or correct automatically- generated captions. It is best to not rely solely on captions when viewing video play_arrow content and to use them alongside other learning resources. Students who are registered with Disability Support Services should be in contact with them to discuss captioning if needed. Powered by Panopto get_app closed_caption fullscreen keyboard_arrow_up Week5-L2-Part1 These captions have been automatically generated. As such, the Week5-L2-Part1 quality is not 100% accurate. Accuracy may be affected by audio quality, topic under discussion and clarity of the speakers. Staff are not expected or required to edit or correct automatically- generated captions. It is best to not rely solely on captions when viewing video play_arrow content and to use them alongside other learning resources. Students who are registered with Disability Support Services should be in contact with them to discuss captioning if needed. Powered by Panopto get_app closed_caption fullscreen keyboard_arrow_up https://learning.monash.edu/mod/book/tool/print/index.php?id=2780423 12/13 8/18/24, 2:44 PM Week 5: Ketones and aldehydes - workbook | MonashELMS1 Week5-L2-Part2 These captions have been automatically generated. As such, the Week5-L2-Part2 quality is not 100% accurate. Accuracy may be affected by audio quality, topic under discussion and clarity of the speakers. Staff are not expected or required to edit or correct automatically- generated captions. It is best to not rely solely on captions when viewing video play_arrow content and to use them alongside other learning resources. Students who are registered with Disability Support Services should be in contact with them to discuss captioning if needed. Powered by Panopto get_app closed_caption fullscreen keyboard_arrow_up Week5-L2-Part3 These captions have been automatically generated. As such, the Week5-L2-Part3 quality is not 100% accurate. Accuracy may be affected by audio quality, topic under discussion and clarity of the speakers. Staff are not expected or required to edit or correct automatically- generated captions. It is best to not rely solely on captions when viewing video play_arrow content and to use them alongside other learning resources. Students who are registered with Disability Support Services should be in contact with them to discuss captioning if needed. Powered by Panopto get_app closed_caption fullscreen keyboard_arrow_up CHM1022 Week5-L2-Part4 These captions have been automatically generated. As such, the Week5-L2-Part4 quality is not 100% accurate. Accuracy may be affected by audio quality, topic under discussion and clarity of the speakers. Staff are not expected or required to edit or correct automatically- generated captions. It is best to not rely solely on captions when viewing video play_arrow content and to use them alongside other learning resources. Students who are registered with Disability Support Services should be in contact with them to discuss captioning if needed. Powered by Panopto get_app closed_caption fullscreen keyboard_arrow_up Online lecture slides can be downloaded from this link: Week 5 lecture slides https://learning.monash.edu/mod/book/tool/print/index.php?id=2780423 13/13