GChemPaint/C3/Resonance-Structures/English-timed

Time	Narration
00:01	Hello everyone.Welcome to this tutorial on Resonance Structures in GChemPaint.
00:06	In this tutorial, we will learn to:
00:09	Use different types of arrows to represent chemical reactions and
00:14	Add charge and electron pairs on an atom.
00:18	For this tutorial, I am using
00:20	Ubuntu Linux OS version 12.04,
00:24	GChemPaint version 0.12.10.
00:29	To follow this tutorial you should be familiar with GChemPaint.
00:34	If not, for relevant tutorials, please visit our website.
00:39	I will switch to GChemPaint window.
00:42	I have opened a new GChemPaint window.
00:45	Here you can see EthylChloride and Methylbromide structures.
00:50	I will show how to obtain a Carbo-cation.
00:55	Let's add a pair of electrons on the Chlorine atom of EthylChloride.
01:01	Click on Add an electron pair tool.
01:04	Click on Chlorine atom and observe what happens.
01:09	Next, I will show an electron pair shift in the Carbon-Chlorine bond.
01:14	Click on Add a curved arrow to represent an electron pair move tool.
01:18	Property window opens.
01:21	Click on End arrow at center of new bond check box.
01:26	It moves the electron pair to the correct position.
01:30	Click on Carbon-Chlorine bond.
01:33	Place the cursor on the curved arrow and observe the electron shift.
01:39	I will make the copy of this structure.
01:42	Now, click on Add an arrow and click between the structures.
01:48	Formation of a Carbo-cation is initialized by a base like Sodium Hydroxide(NaOH).
01:54	Click on Add or modify a group of atoms tool, click above the arrow.
02:00	Type NaOH.
02:04	Click on Selection tool and select NaOH.
02:09	Right-click on the arrow.
02:12	In the sub-menu, select Arrow.
02:13	Click on Attach selection to arrow.
02:18	A dialog box with heading Arrow associated appears.
02:23	In the Role drop-down, select “Reactant” and click on Close.
02:29	Now, let's convert second EthylChloride to Ethyl Carbo-cation and Chloride ions.
02:36	Click on Eraser tool and click on Carbon-chlorine bond.
02:42	Ethane(CH3-CH3) and HCl are formed.
02:45	When electrons shift from Carbon to Chlorine, Carbon gains a positive charge.
02:51	Click on Increment the charge tool.
02:54	Click at the position from where Carbon-chlorine bond was deleted.
02:59	Ethyl Carbo-cation(CH3-CH2^+) is formed.
03:02	To form Chloride ion, click on Decrement the charge tool.
03:07	Click on HCl. Chloride(Cl^-) ion is formed.
03:12	Now let's move to single electron shift.
03:15	Let's use the Methylbromide structure to obtain free radicals.
03:20	Click on Add a curved arrow to represent a single electron move tool.
03:26	Click on Methylbromide bond to obtain a curved arrow.
03:30	Shift the Pencil tool a little on the bond, click again to get second curved arrow.
03:38	One arrow moves to bromo(Br) and other arrow moves towards methyl(CH3).
03:44	Both Bromo(Br) and methyl(CH3) will get one electron each from the bonded pair of electrons.
03:51	To show the products, let us add an arrow.
03:54	Click on Add an arrow, click on Display area beside Methylbromide.
04:00	Formation of free radicals involves heat in the reaction.
04:04	Click on Add or modify a text tool.
04:08	Click on the Display area above the arrow.
04:11	Type “Heat” in the green box.
04:14	Click on Selection tool and select “Heat”.
04:19	Right-click on the arrow.
04:21	In the Sub-menu select Arrow and Click on Attach selection to arrow.
04:27	A dialog box with heading Arrow associated appears.
04:32	Notice that Role drop down list has more options.
04:37	In the Role drop-down, select “Temperature” and
04:40	click on Close.
04:43	Now let's create the free radicals.
04:46	I will make a copy of this structure.
04:50	Click on Eraser tool and click on Carbon-bromine bond.
04:55	Methane(CH4) and Hydrogen-bromide(HBr) are formed.
04:59	Click on Add an unpaired electron tool.
05:02	Click on Methane(CH4) and Hydrogen-bromide(HBr)
05:06	Methyl(CH3) and Bromium(Br) free radicals are formed.
05:10	Click on Selection tool.
05:12	To create a reaction pathway, first select the complete reaction.
05:17	Now, right-click on the selection.
05:20	A sub-menu opens.
05:22	Click on Create a new reaction.
05:25	Reaction path is created.
05:28	Drag to see the reaction pathway.
05:30	Likewise, I will create the reaction pathway for the previous reaction.
05:37	We can also remove the reaction pathway, if we want to.
05:41	To do so, right-click on the reaction again.
05:45	Click on Destroy the reaction.
05:48	This action will remove the reaction pathway.
05:51	Drag any of the objects, and you will see that they can be moved individually.
05:57	Now we move on to Resonance or Mesomery using double headed arrow.
06:02	I have opened a new GChemPaint window with structures of Nitromethane.
06:08	I had added curved arrows and charges to show electron shifts within the structures.
06:14	Now let's add a double headed arrow.
06:16	Click on Add a double headed arrow.
06:20	Click on the Display area in between Nitromethanes.
06:25	The two structures are "Resonance structures" of Nitromethane.
06:30	Press Ctrl+A to select the structures.
06:33	Right-click on the selection.
06:35	A sub-menu opens.
06:37	Click on Create a new mesomery relationship.
06:41	Drag to see the relationship.
06:44	Here is slide for the Resonance Structures of Benzene.
06:48	Now, let's learn to create a retro-synthetic pathway.
06:52	I have opened a new GChemPaint window with the required structures.
06:57	Retrosynthetic pathway starts with the product and goes to the reactant along with all the intermediates.
07:04	In this pathway, the final product is Ortho-nitrophenol and the starting material is Benzene.
07:10	Let us add a retro-synthetic arrow, to show the retro-synthetic pathway.
07:15	Click on Add an arrow for a retrosynthetic step.
07:20	Click between all the compounds.
07:25	Press Ctrl+A to select the structures.
07:28	Right click on the selection.
07:30	A sub-menu opens.
07:32	Click on Create a new retrosynthesis pathway.
07:36	Drag to see the created pathway.
07:39	Let's summarize what we have learnt.
07:41	In this tutorial we have learnt to:
07:44	Show electron shifts using curved arrows
07:48	Attach reaction conditions to reaction arrows.
07:52	Create and destroy reaction pathway using a reaction arrow
07:57	Create a new mesomery relationship using double headed arrow
08:01	Create a retro-synthetic pathway using retro-synthetic arrow.
08:06	As an assignment,using arrow properties-
08:10	1. Create a reaction pathway for the reaction of Bromo-Ethane (C2H5Br) and Sodium(Na) with solvent Dryether to get Butane & Sodiumbromide.
08:20	2. Add stoichiometric coefficients to reaction molecules.
08:24	3. Draw resonance structures of Naphthalene, Anthracene and Carbon-dioxide.
08:30	This is the required reaction pathway.
08:33	These are the resonance structures of Naphthalene, Anthracene and Carbon-dioxide.
08:39	Watch the video available at this URL. http://spoken-tutorial.org/What_is_a_Spoken_ Tutorial
08:43	It summarizes the Spoken Tutorial project.
08:45	If you do not have good bandwidth, you can download and watch it
08:50	The Spoken Tutorial Project Team: Conducts workshops using spoken tutorials.
08:54	Gives certificates to those who pass an on-line test.
08:57	For more details, please write to contact@spoken-tutorial.org.
09:03	Spoken Tutorial Project is a part of the Talk to a Teacher project.
09:08	It is supported by the National Mission on Education through ICT, MHRD, Government of India.
09:16	More information on this Mission is available at this link http://spoken-tutorial.org/NMEICT-Intro].
09:21	This is Madhuri Ganapathi from IIT Bombay signing off. Thank you for joining.

Contributors and Content Editors

Gaurav, PoojaMoolya, Pratik kamble, Sandhya.np14