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Dr. Laurie Starkey

Dr. Laurie Starkey

Completing the Reagent Table for Prelab

Slide Duration:

Table of Contents

I. Reagent Table
Completing the Reagent Table for Prelab

21m 9s

Intro
0:00
Sample Reagent Table
0:11
Reagent Table Overview
0:12
Calculate Moles of 2-bromoaniline
6:44
Calculate Molar Amounts of Each Reagent
9:20
Calculate Mole of NaNO₂
9:21
Calculate Moles of KI
10:33
Identify the Limiting Reagent
11:17
Which Reagent is the Limiting Reagent?
11:18
Calculate Molar Equivalents
13:37
Molar Equivalents
13:38
Calculate Theoretical Yield
16:40
Theoretical Yield
16:41
Calculate Actual Yield (%Yield)
18:30
Actual Yield (%Yield)
18:31
II. Melting Points
Introduction to Melting Points

16m 10s

Intro
0:00
Definition of a Melting Point (mp)
0:04
Definition of a Melting Point (mp)
0:05
Solid Samples Melt Gradually
1:49
Recording Range of Melting Temperature
2:04
Melting Point Theory
3:14
Melting Point Theory
3:15
Effects of Impurities on a Melting Point
3:57
Effects of Impurities on a Melting Point
3:58
Special Exception: Eutectic Mixtures
5:09
Freezing Point Depression by Solutes
5:39
Melting Point Uses
6:19
Solid Compound
6:20
Determine Purity of a Sample
6:42
Identify an Unknown Solid
7:06
Recording a Melting Point
9:03
Pack 1-3 mm of Dry Powder in MP Tube
9:04
Slowly Heat Sample
9:55
Record Temperature at First Sign of Melting
10:33
Record Temperature When Last Crystal Disappears
11:26
Discard MP Tube in Glass Waste
11:32
Determine Approximate MP
11:42
Tips, Tricks and Warnings
12:28
Use Small, Tightly Packed Sample
12:29
Be Sure MP Apparatus is Cool
12:45
Never Reuse a MP Tube
13:16
Sample May Decompose
13:30
If Pure Melting Point (MP) Doesn't Match Literature
14:20
Melting Point Lab

8m 17s

Intro
0:00
Melting Point Tubes
0:40
Melting Point Apparatus
3:42
Recording a melting Point
5:50
III. Recrystallization
Introduction to Recrystallization

22m

Intro
0:00
Crystallization to Purify a Solid
0:10
Crude Solid
0:11
Hot Solution
0:20
Crystals
1:09
Supernatant Liquid
1:20
Theory of Crystallization
2:34
Theory of Crystallization
2:35
Analysis and Obtaining a Second Crop
3:40
Crystals → Melting Point, TLC
3:41
Supernatant Liquid → Crude Solid → Pure Solid
4:18
Crystallize Again → Pure Solid (2nd Crop)
4:32
Choosing a Solvent
5:19
1. Product is Very Soluble at High Temperatures
5:20
2. Product has Low Solubility at Low Temperatures
6:00
3. Impurities are Soluble at All Temperatures
6:16
Check Handbooks for Suitable Solvents
7:33
Why Isn't This Dissolving?!
8:46
If Solid Remains When Solution is Hot
8:47
Still Not Dissolved in Hot Solvent?
10:18
Where Are My Crystals?!
12:23
If No Crystals Form When Solution is Cooled
12:24
Still No Crystals?
14:59
Tips, Tricks and Warnings
16:26
Always Use a Boiling Chip or Stick!
16:27
Use Charcoal to Remove Colored Impurities
16:52
Solvent Pairs May Be Used
18:23
Product May 'Oil Out'
20:11
Recrystallization Lab

19m 7s

Intro
0:00
Step 1: Dissolving the Solute in the Solvent
0:12
Hot Filtration
6:33
Step 2: Cooling the Solution
8:01
Step 3: Filtering the Crystals
12:08
Step 4: Removing & Drying the Crystals
16:10
IV. Distillation
Introduction to Distillation

25m 54s

Intro
0:00
Distillation: Purify a Liquid
0:04
Simple Distillation
0:05
Fractional Distillation
0:55
Theory of Distillation
1:04
Theory of Distillation
1:05
Vapor Pressure and Volatility
1:52
Vapor Pressure
1:53
Volatile Liquid
2:28
Less Volatile Liquid
3:09
Vapor Pressure vs. Boiling Point
4:03
Vapor Pressure vs. Boiling Point
4:04
Increasing Vapor Pressure
4:38
The Purpose of Boiling Chips
6:46
The Purpose of Boiling Chips
6:47
Homogeneous Mixtures of Liquids
9:24
Dalton's Law
9:25
Raoult's Law
10:27
Distilling a Mixture of Two Liquids
11:41
Distilling a Mixture of Two Liquids
11:42
Simple Distillation: Changing Vapor Composition
12:06
Vapor & Liquid
12:07
Simple Distillation: Changing Vapor Composition
14:47
Azeotrope
18:41
Fractional Distillation: Constant Vapor Composition
19:42
Fractional Distillation: Constant Vapor Composition
19:43
Distillation Lab

24m 13s

Intro
0:00
Glassware Overview
0:04
Heating a Sample
3:09
Bunsen Burner
3:10
Heating Mantle 1
4:45
Heating Mantle 2
6:18
Hot Plate
7:10
Simple Distillation Lab
8:37
Fractional Distillation Lab
17:13
Removing the Distillation Set-Up
22:41
V. Chromatography
Introduction to TLC (Thin-Layer Chromatography)

28m 51s

Intro
0:00
Chromatography
0:06
Purification & Analysis
0:07
Types of Chromatography: Thin-layer, Column, Gas, & High Performance Liquid
0:24
Theory of Chromatography
0:44
Theory of Chromatography
0:45
Performing a Thin-layer Chromatography (TLC) Analysis
2:30
Overview: Thin-layer Chromatography (TLC) Analysis
2:31
Step 1: 'Spot' the TLC Plate
4:11
Step 2: Prepare the Developing Chamber
5:54
Step 3: Develop the TLC Plate
7:30
Step 4: Visualize the Spots
9:02
Step 5: Calculate the Rf for Each Spot
12:00
Compound Polarity: Effect on Rf
16:50
Compound Polarity: Effect on Rf
16:51
Solvent Polarity: Effect on Rf
18:47
Solvent Polarity: Effect on Rf
18:48
Example: EtOAc & Hexane
19:35
Other Types of Chromatography
22:27
Thin-layer Chromatography (TLC)
22:28
Column Chromatography
22:56
High Performance Liquid (HPLC)
23:59
Gas Chromatography (GC)
24:38
Preparative 'prep' Scale Possible
28:05
TLC Analysis Lab

20m 50s

Intro
0:00
Step 1: 'Spot' the TLC Plate
0:06
Step 2: Prepare the Developing Chamber
4:06
Step 3: Develop the TLC Plate
6:26
Step 4: Visualize the Spots
7:45
Step 5: Calculate the Rf for Each Spot
11:48
How to Make Spotters
12:58
TLC Plate
16:04
Flash Column Chromatography
17:11
VI. Extractions
Introduction to Extractions

34m 25s

Intro
0:00
Extraction Purify, Separate Mixtures
0:07
Adding a Second Solvent
0:28
Mixing Two Layers
0:38
Layers Settle
0:54
Separate Layers
1:05
Extraction Uses
1:20
To Separate Based on Difference in Solubility/Polarity
1:21
To Separate Based on Differences in Reactivity
2:11
Separate & Isolate
2:20
Theory of Extraction
3:03
Aqueous & Organic Phases
3:04
Solubility: 'Like Dissolves Like'
3:25
Separation of Layers
4:06
Partitioning
4:14
Distribution Coefficient, K
5:03
Solutes Partition Between Phases
5:04
Distribution Coefficient, K at Equilibrium
6:27
Acid-Base Extractions
8:09
Organic Layer
8:10
Adding Aqueous HCl & Mixing Two Layers
8:46
Neutralize (Adding Aqueous NaOH)
10:05
Adding Organic Solvent Mix Two Layers 'Back Extract'
10:24
Final Results
10:43
Planning an Acid-Base Extraction, Part 1
11:01
Solute Type: Neutral
11:02
Aqueous Solution: Water
13:40
Solute Type: Basic
14:43
Solute Type: Weakly Acidic
15:23
Solute Type: Acidic
16:12
Planning an Acid-Base Extraction, Part 2
17:34
Planning an Acid-Base Extraction
17:35
Performing an Extraction
19:34
Pour Solution into Sep Funnel
19:35
Add Second Liquid
20:07
Add Stopper, Cover with Hand, Remove from Ring
20:48
Tip Upside Down, Open Stopcock to Vent Pressure
21:00
Shake to Mix Two Layers
21:30
Remove Stopper & Drain Bottom Layer
21:40
Reaction Work-up: Purify, Isolate Product
22:03
Typical Reaction is Run in Organic Solvent
22:04
Starting a Reaction Work-up
22:33
Extracting the Product with Organic Solvent
23:17
Combined Extracts are Washed
23:40
Organic Layer is 'Dried'
24:23
Finding the Product
26:38
Which Layer is Which?
26:39
Where is My Product?
28:00
Tips, Tricks and Warnings
29:29
Leaking Sep Funnel
29:30
Caution When Mixing Layers & Using Ether
30:17
If an Emulsion Forms
31:51
Extraction Lab

14m 49s

Intro
0:00
Step 1: Preparing the Separatory Funnel
0:03
Step 2: Adding Sample
1:18
Step 3: Mixing the Two Layers
2:59
Step 4: Draining the Bottom Layers
4:59
Step 5: Performing a Second Extraction
5:50
Step 6: Drying the Organic Layer
7:21
Step 7: Gravity Filtration
9:35
Possible Extraction Challenges
12:55
VII. Spectroscopy
Infrared Spectroscopy, Part I

1h 4m

Intro
0:00
Infrared (IR) Spectroscopy
0:09
Introduction to Infrared (IR) Spectroscopy
0:10
Intensity of Absorption Is Proportional to Change in Dipole
3:08
IR Spectrum of an Alkane
6:08
Pentane
6:09
IR Spectrum of an Alkene
13:12
1-Pentene
13:13
IR Spectrum of an Alkyne
15:49
1-Pentyne
15:50
IR Spectrum of an Aromatic Compound
18:02
Methylbenzene
18:24
IR of Substituted Aromatic Compounds
24:04
IR of Substituted Aromatic Compounds
24:05
IR Spectrum of 1,2-Disubstituted Aromatic
25:30
1,2-dimethylbenzene
25:31
IR Spectrum of 1,3-Disubstituted Aromatic
27:15
1,3-dimethylbenzene
27:16
IR Spectrum of 1,4-Disubstituted Aromatic
28:41
1,4-dimethylbenzene
28:42
IR Spectrum of an Alcohol
29:34
1-pentanol
29:35
IR Spectrum of an Amine
32:39
1-butanamine
32:40
IR Spectrum of a 2° Amine
34:50
Diethylamine
34:51
IR Spectrum of a 3° Amine
35:47
Triethylamine
35:48
IR Spectrum of a Ketone
36:41
2-butanone
36:42
IR Spectrum of an Aldehyde
40:10
Pentanal
40:11
IR Spectrum of an Ester
42:38
Butyl Propanoate
42:39
IR Spectrum of a Carboxylic Acid
44:26
Butanoic Acid
44:27
Sample IR Correlation Chart
47:36
Sample IR Correlation Chart: Wavenumber and Functional Group
47:37
Predicting IR Spectra: Sample Structures
52:06
Example 1
52:07
Example 2
53:29
Example 3
54:40
Example 4
57:08
Example 5
58:31
Example 6
59:07
Example 7
1:00:52
Example 8
1:02:20
Infrared Spectroscopy, Part II

48m 34s

Intro
0:00
Interpretation of IR Spectra: a Basic Approach
0:05
Interpretation of IR Spectra: a Basic Approach
0:06
Other Peaks to Look for
3:39
Examples
5:17
Example 1
5:18
Example 2
9:09
Example 3
11:52
Example 4
14:03
Example 5
16:31
Example 6
19:31
Example 7
22:32
Example 8
24:39
IR Problems Part 1
28:11
IR Problem 1
28:12
IR Problem 2
31:14
IR Problem 3
32:59
IR Problem 4
34:23
IR Problem 5
35:49
IR Problem 6
38:20
IR Problems Part 2
42:36
IR Problem 7
42:37
IR Problem 8
44:02
IR Problem 9
45:07
IR Problems10
46:10
Nuclear Magnetic Resonance (NMR) Spectroscopy, Part I

1h 32m 14s

Intro
0:00
Purpose of NMR
0:14
Purpose of NMR
0:15
How NMR Works
2:17
How NMR Works
2:18
Information Obtained From a ¹H NMR Spectrum
5:51
# of Signals, Integration, Chemical Shifts, and Splitting Patterns
5:52
Number of Signals in NMR (Chemical Equivalence)
7:52
Example 1: How Many Signals in ¹H NMR?
7:53
Example 2: How Many Signals in ¹H NMR?
9:36
Example 3: How Many Signals in ¹H NMR?
12:15
Example 4: How Many Signals in ¹H NMR?
13:47
Example 5: How Many Signals in ¹H NMR?
16:12
Size of Signals in NMR (Peak Area or Integration)
21:23
Size of Signals in NMR (Peak Area or Integration)
21:24
Using Integral Trails
25:15
Example 1: C₈H₁₈O
25:16
Example 2: C₃H₈O
27:17
Example 3: C₇H₈
28:21
Location of NMR Signal (Chemical Shift)
29:05
Location of NMR Signal (Chemical Shift)
29:06
¹H NMR Chemical Shifts
33:20
¹H NMR Chemical Shifts
33:21
¹H NMR Chemical Shifts (Protons on Carbon)
37:03
¹H NMR Chemical Shifts (Protons on Carbon)
37:04
Chemical Shifts of H's on N or O
39:01
Chemical Shifts of H's on N or O
39:02
Estimating Chemical Shifts
41:13
Example 1: Estimating Chemical Shifts
41:14
Example 2: Estimating Chemical Shifts
43:22
Functional Group Effects are Additive
45:28
Calculating Chemical Shifts
47:38
Methylene Calculation
47:39
Methine Calculation
48:20
Protons on sp³ Carbons: Chemical Shift Calculation Table
48:50
Example: Estimate the Chemical Shift of the Selected H
50:29
Effects of Resonance on Chemical Shifts
53:11
Example 1: Effects of Resonance on Chemical Shifts
53:12
Example 2: Effects of Resonance on Chemical Shifts
55:09
Example 3: Effects of Resonance on Chemical Shifts
57:08
Shape of NMR Signal (Splitting Patterns)
59:17
Shape of NMR Signal (Splitting Patterns)
59:18
Understanding Splitting Patterns: The 'n+1 Rule'
1:01:24
Understanding Splitting Patterns: The 'n+1 Rule'
1:01:25
Explanation of n+1 Rule
1:02:42
Explanation of n+1 Rule: One Neighbor
1:02:43
Explanation of n+1 Rule: Two Neighbors
1:06:23
Summary of Splitting Patterns
1:06:24
Summary of Splitting Patterns
1:10:45
Predicting ¹H NMR Spectra
1:10:46
Example 1: Predicting ¹H NMR Spectra
1:13:30
Example 2: Predicting ¹H NMR Spectra
1:19:07
Example 3: Predicting ¹H NMR Spectra
1:23:50
Example 4: Predicting ¹H NMR Spectra
1:29:27
Nuclear Magnetic Resonance (NMR) Spectroscopy, Part II

2h 3m 48s

Intro
0:00
¹H NMR Problem-Solving Strategies
0:18
Step 1: Analyze IR Spectrum (If Provided)
0:19
Step 2: Analyze Molecular Formula (If Provided)
2:06
Step 3: Draw Pieces of Molecule
3:49
Step 4: Confirm Piecs
6:30
Step 5: Put the Pieces Together!
7:23
Step 6: Check Your Answer!
8:21
Examples
9:17
Example 1: Determine the Structure of a C₉H₁₀O₂ Compound with the Following ¹H NMR Data
9:18
Example 2: Determine the Structure of a C₉H₁₀O₂ Compound with the Following ¹H NMR Data
17:27
¹H NMR Practice
20:57
¹H NMR Practice 1: C₁₀H₁₄
20:58
¹H NMR Practice 2: C₄H₈O₂
29:50
¹H NMR Practice 3: C₆H₁₂O₃
39:19
¹H NMR Practice 4: C₈H₁₈
50:19
More About Coupling Constants (J Values)
57:11
Vicinal (3-bond) and Geminal (2-bond)
57:12
Cyclohexane (ax-ax) and Cyclohexane (ax-eq) or (eq-eq)
59:50
Geminal (Alkene), Cis (Alkene), and Trans (Alkene)
1:02:40
Allylic (4-bond) and W-coupling (4-bond) (Rigid Structures Only)
1:04:05
¹H NMR Advanced Splitting Patterns
1:05:39
Example 1: ¹H NMR Advanced Splitting Patterns
1:05:40
Example 2: ¹H NMR Advanced Splitting Patterns
1:10:01
Example 3: ¹H NMR Advanced Splitting Patterns
1:13:45
¹H NMR Practice
1:22:53
¹H NMR Practice 5: C₁₁H₁₇N
1:22:54
¹H NMR Practice 6: C₉H₁₀O
1:34:04
¹³C NMR Spectroscopy
1:44:49
¹³C NMR Spectroscopy
1:44:50
¹³C NMR Chemical Shifts
1:47:24
¹³C NMR Chemical Shifts Part 1
1:47:25
¹³C NMR Chemical Shifts Part 2
1:48:59
¹³C NMR Practice
1:50:16
¹³C NMR Practice 1
1:50:17
¹³C NMR Practice 2
1:58:30
Mass Spectrometry

1h 28m 35s

Intro
0:00
Introduction to Mass Spectrometry
0:37
Uses of Mass Spectrometry: Molecular Mass
0:38
Uses of Mass Spectrometry: Molecular Formula
1:04
Uses of Mass Spectrometry: Structural Information
1:21
Uses of Mass Spectrometry: In Conjunction with Gas Chromatography
2:03
Obtaining a Mass Spectrum
2:59
Obtaining a Mass Spectrum
3:00
The Components of a Mass Spectrum
6:44
The Components of a Mass Spectrum
6:45
What is the Mass of a Single Molecule
12:13
Example: CH₄
12:14
Example: ¹³CH₄
12:51
What Ratio is Expected for the Molecular Ion Peaks of C₂H₆?
14:20
Other Isotopes of High Abundance
16:30
Example: Cl Atoms
16:31
Example: Br Atoms
18:33
Mass Spectrometry of Chloroethane
19:22
Mass Spectrometry of Bromobutane
21:23
Isotopic Abundance can be Calculated
22:48
What Ratios are Expected for the Molecular Ion Peaks of CH₂Br₂?
22:49
Determining Molecular Formula from High-resolution Mass Spectrometry
26:53
Exact Masses of Various Elements
26:54
Fragmentation of various Functional Groups
28:42
What is More Stable, a Carbocation C⁺ or a Radical R?
28:43
Fragmentation is More Likely If It Gives Relatively Stable Carbocations and Radicals
31:37
Mass Spectra of Alkanes
33:15
Example: Hexane
33:16
Fragmentation Method 1
34:19
Fragmentation Method 2
35:46
Fragmentation Method 3
36:15
Mass of Common Fragments
37:07
Mass of Common Fragments
37:08
Mass Spectra of Alkanes
39:28
Mass Spectra of Alkanes
39:29
What are the Peaks at m/z 15 and 71 So Small?
41:01
Branched Alkanes
43:12
Explain Why the Base Peak of 2-methylhexane is at m/z 43 (M-57)
43:13
Mass Spectra of Alkenes
45:42
Mass Spectra of Alkenes: Remove 1 e⁻
45:43
Mass Spectra of Alkenes: Fragment
46:14
High-Energy Pi Electron is Most Likely Removed
47:59
Mass Spectra of Aromatic Compounds
49:01
Mass Spectra of Aromatic Compounds
49:02
Mass Spectra of Alcohols
51:32
Mass Spectra of Alcohols
51:33
Mass Spectra of Ethers
54:53
Mass Spectra of Ethers
54:54
Mass Spectra of Amines
56:49
Mass Spectra of Amines
56:50
Mass Spectra of Aldehydes & Ketones
59:23
Mass Spectra of Aldehydes & Ketones
59:24
McLafferty Rearrangement
1:01:29
McLafferty Rearrangement
1:01:30
Mass Spectra of Esters
1:04:15
Mass Spectra of Esters
1:01:16
Mass Spectrometry Discussion I
1:05:01
For the Given Molecule (M=58), Do You Expect the More Abundant Peak to Be m/z 15 or m/z 43?
1:05:02
Mass Spectrometry Discussion II
1:08:13
For the Given Molecule (M=74), Do You Expect the More Abundant Peak to Be m/z 31, m/z 45, or m/z 59?
1:08:14
Mass Spectrometry Discussion III
1:11:42
Explain Why the Mass Spectra of Methyl Ketones Typically have a Peak at m/z 43
1:11:43
Mass Spectrometry Discussion IV
1:14:46
In the Mass Spectrum of the Given Molecule (M=88), Account for the Peaks at m/z 45 and m/z 57
1:14:47
Mass Spectrometry Discussion V
1:18:25
How Could You Use Mass Spectrometry to Distinguish Between the Following Two Compounds (M=73)?
1:18:26
Mass Spectrometry Discussion VI
1:22:45
What Would be the m/z Ratio for the Fragment for the Fragment Resulting from a McLafferty Rearrangement for the Following Molecule (M=114)?
1:22:46
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Lecture Comments (16)

1 answer

Last reply by: Professor Starkey
Sat Aug 25, 2018 7:01 PM

Post by Dakla de Souza Lima on August 15 at 11:41:14 AM

Professor, if my ratio it isn't 1:1, how that I do to find the molar equivalent?

1 answer

Last reply by: Professor Starkey
Sun Apr 15, 2018 12:45 PM

Post by Peter Garney on April 14 at 11:18:42 AM

Is this the only lecture on ogarnic lab

1 answer

Last reply by: Professor Starkey
Fri Oct 21, 2016 12:46 AM

Post by Hector Flores on October 21, 2016

This question is not concerning this lecture...you dont have any lab videos on the grignard lab? :(

1 answer

Last reply by: Professor Starkey
Sat Sep 5, 2015 2:43 PM

Post by David Steele on September 5, 2015

are you going to talk about this. https://en.m.wikipedia.org/wiki/Enzyme_kinetics
where can i learn about this.

5 answers

Last reply by: Professor Starkey
Thu Jul 23, 2015 3:07 PM

Post by Akilah Futch on July 22, 2015

Professor, is it possible to calculate Moles if mass(g) is not given, but molarity is given?

1 answer

Last reply by: Professor Starkey
Fri May 1, 2015 1:57 PM

Post by Rene Whitaker on May 1, 2015

Wow, I wish this had been available when I started organic chemistry!  I have been watching your other o-chem videos religiously to get me through the lecture class (with A's so far...orgo II final is in 3 days)!  Just want to say I am forever grateful to you for the help!!!  Unfortunately, I still have less than stellar synthesis skills...sigh.

Completing the Reagent Table for Prelab

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • Sample Reagent Table 0:11
    • Reagent Table Overview
    • Calculate Moles of 2-bromoaniline
  • Calculate Molar Amounts of Each Reagent 9:20
    • Calculate Mole of NaNO₂
    • Calculate Moles of KI
  • Identify the Limiting Reagent 11:17
    • Which Reagent is the Limiting Reagent?
  • Calculate Molar Equivalents 13:37
    • Molar Equivalents
  • Calculate Theoretical Yield 16:40
    • Theoretical Yield
  • Calculate Actual Yield (%Yield) 18:30
    • Actual Yield (%Yield)

Transcription: Completing the Reagent Table for Prelab

Hi and welcome back to www.educator.com.0000

Today, we are going to talk about how to complete the reagent table in your lab notebook,0002

before you do a synthesis experiment.0007

Here is a sample reagent table and there is a reaction taking place here.0012

For right now, it is not important to understand how this reaction takes place.0018

What you do need to know is that all of the reagents react an equal molar amount.0022

In other words, it takes one molecule of 2-bromoaniline and one equivalent of sodium nitrite, and HCl.0031

I’m sorry, not HCl, we have that in excess.0041

But we need the sodium nitrite and the potassium iodide, all 1 to 1 to 1 to make one product of this iodide.0044

As long as we know the stoichiometry of the reaction then that is all we need to do our calculations.0055

I put together a sample reagent table.0062

This is not necessarily the format that every instructor wants.0065

Make sure you follow the format that is required for your instructor.0068

What we have listed here are the reagents.0073

This is like our ingredient list for the recipe of the reaction that we are going to be doing.0076

This first item listed, I would describe as my starting material or maybe the reactant.0081

That is the organic species that is undergoing synthetic transformation.0095

These guys, I would all describe as reagents.0101

These are the chemicals that are causing the reaction to take place.0106

The water in this case is my solvent.0110

Almost all reactions on are run in some kind of solvent.0113

In this case, it is water used as an organic solvent.0117

Anyway, we are going to list everything that goes into the reaction at the start.0120

Some instructors also want included in the reagent table all of the materials used in the work up procedure.0125

You are kind of making sure that you know everything about everything you are using that whole day.0131

But in this table, all I have are the actual reagents that are used for the transformation to take place in the solvent.0136

That is going to be used when we mix all these together.0144

Very much like a recipe list, when you are going to bake some cookies.0147

I also have a separate row.0154

I separated it by a line there, I have separate row to list my product.0157

The product is not something that is going into the reaction.0161

It is something we are going to be isolating at the end of the reaction.0164

But this is a very nice place to include information about your product.0166

This is kind of one stop shopping for all of your physical properties in your information.0170

It is a good practice to get into to include your product here.0173

For each of these, I have listed the molecular weights, the formula for each of the compounds.0178

HCL is being added as an aqueous solution.0185

We do not care about its molecular weight here.0190

We could maybe put the molarity.0193

I did not include that in this example because we are just using the big excess of that.0194

But this is maybe where we put the molarity, you have to calculate the moles of HCl, if you needed to.0198

Water, I did not include the molecular weight of water because that is my solvent,0205

that is not being used stoichiometrically in the reaction.0209

That is not relevant information.0212

Each instructor is different, they might want all of your formula weights here but that was not important to me.0215

And then, I have a column for density.0220

Density, I only put liquid compounds which are 2-bromoaniline0222

happens to be a liquid and their product also happens to be a liquid.0227

I have looked up the densities for those so that you can use the CRC handbook0230

or something like that to find densities or molecular weights, formula weights.0235

But really, you could use like Wikipedia for this, most common reagents and reactants0240

you are going to find organic compounds.0249

You are going to find Wikipedia pages for and the data that is in that is really robust, it is really reliable.0251

It is a great place to go to find physical properties and molecular masses and all that kind of stuff.0257

Do not hesitate to use that if you want to, as well.0263

These amounts are coming from the experimental procedure.0265

Read through the experimental procedure and it said something like 2ml of 2-bromoaniline are dissolved in 10ml of water.0269

And then, 1.9g of sodium nitrite was added to that, and so on.0276

These are the amounts that you need to get from the procedure.0281

Notice that I'm including the units here because each of these has their own units.0286

Now the units for molecular mass are known, those are grams per mol.0291

The formula would always tells us how many, if you had 1mol of this compound, how many grams would it be.0297

Density is always given in grams per milliliter.0306

If you have a hard time remembering that unit, remember the density of water is 1.0310

If you have 1g of water, it is going to be 1ml of or cc, or is that going to be a liter of water?0316

That does not sound right, a gram is a very small amount.0324

1cc or 1ml of water only weighs 1g.0327

That is how we can remember the units for density is g/ml.0331

Then, we have a column here and I do not have an amount for my product,0339

because the procedure did not tell me how much product I’m going to get.0342

I have to calculate that.0348

And then I have a column for moles; what I'm going to do is convert all of these amounts to mole,0350

so that we compare one species to another.0354

I have another column for equivalents, molar equivalents, and that is just a more simple way to express this molar amount.0357

We will talk about that too.0365

And then, I always just have this final column called remarks and that is where I put any other relevant data.0366

This is a place where you can put hazards.0372

For example, that HCl is corrosive, we want to put a note of that.0376

You can put melting points for solids, boiling points for liquids.0381

Any information here, if you are reading through the procedure and says all watch out for this or take care about this.0385

This is a place to put that.0392

Again, some instructors will always want a column for boiling point and a column for melting point, and so on.0394

For me, this is kind of a catch-all place to put anything else that is pertinent about each species.0399

Let us start doing our reagent table calculations.0405

One by one, the first thing we want to do is convert these amounts to moles.0410

We can start with our first one listed, our 2-bromoaniline is our starting material.0416

We need to figure out how many moles that is but we are given the volume.0422

We know that we are using 2ml of 2-bromoaniline.0427

You cannot convert directly from ml to mol.0431

But we could use the density to convert from volume to mass.0435

And then, we can use the molecular weight to go from mass to mol.0440

What we are going to do is, this is 2.0 ml of the 2-bromoaniline.0444

Do not forget to use units but then also because0450

we have so many species that we are dealing with in this particular reaction,0454

you also want to include who it is you are looking at.0458

This should also be included in your lab notebook.0462

This should be something shown in your calculations, so that you could track back if you have an error anywhere.0464

How do we go from ml to g?0469

I know it is 1.56g for every 1ml.0473

Every 1ml weighs 1.56g.0479

Remember, it is g/ml.0481

I want to put it like this so that the ml cancels.0484

In other words, I’m going to multiply my volume in ml × my density to now being g.0488

Now I want to go from g to mol.0496

I know it is 172g for every mol.0498

I’m going to put the 172g in the denominator so that those will cancel.0501

Every 1mol has 172g of 2-bromoaniline.0506

Now my grams cancel.0511

And then, when we do that math, we get 0.018 mol of 2-bromoaniline.0515

It looks like there is two sig figs through each of this.0524

It is reasonable why I have two sig figs here, maybe an extra one.0528

Again, each instructor is a little different about how much they care about this.0531

This is also the same as saying 18mmol.0534

A lot of times our reactions are done at very small scale.0538

It makes sense to talk in terms of mmol instead of mol.0542

If you want to change the title of this column to be mmol, you can do that if you want it.0545

We will keep it as mol, I will say 0.018 is our mol of 2-bromoaniline.0551

Let us move on to our next one.0558

Now let us calculate the mol of NaNO₂.0562

Now we are given a mass of NaNO₂.0566

We are starting with 1.9g of NaNO₂.0569

So we can use our formula weight to immediately convert from grams to mol.0573

It is 69g of NaNO₂, for every 1 mol.0580

Again, in effect what we are doing is dividing by the formula weight.0586

If you always do the work and you can see that your units cancel,0589

then you do not have to memorize whether you are multiplying or dividing.0594

You just always put the numbers in the right place so that our units are canceling.0597

Let us see when we do that math, we get 0.028 mol of NaNO₂ or 28mmol of NaNO₂.0602

We are just going to fill out our chart, our reagent table like this.0612

Like I said, the HCl is just in excess, I already put that in there because it was not significant.0616

But if you had your molarity here, you could calculate your mol, and so on.0622

But sometimes, things are in catalytic amounts or huge excess amounts.0626

You are not required to calculate those.0631

How about finally mol of potassium iodide, our last reagent?0635

We start with 3.6g of KI.0639

Every 1mol of KI, we can put in our species here to weigh 166g.0644

Our grams cancel and we are going to do 3.6 divided by 166, we get 0.022 mol of potassium iodide.0654

We put that in our table as well.0665

One by one, we are going to calculate the mol of every one of our reagents that are added.0667

I do not care how many mol of solvent there are, that is not relevant.0672

It is not involved in the reaction.0675

The next thing we need to do is we need to figure out which of these reagents is the limiting reagent.0679

What is the limiting reagent mean?0685

It is the reagent with the smallest number of mol.0687

Now we have to be careful because sometimes a reagent is not used stoichiometrically in the reaction.0690

Sometimes an acid catalyst is needed or a base catalyst, perhaps.0697

We only need a catalytic amount meaning we do not need a full equivalent of that,0701

in order to convert 1mol of starting material of the product, we do not need a whole mol of the catalyst.0707

Even though we have a very small amount of that, that is not going to limit the amount of product that we can get.0712

Because remember, a catalyst is not consumed in the reactions.0719

Even though, I have a very tiny amount of it, it will get used but then it will get regenerated.0722

I can keep using that tiny amount and convert that whole amount of the starting material to product.0729

Keeping in mind that we are going to ignore the catalyst and0735

this is where we do need to know for this mystery reaction that we have never seen before, that each of these is used.0737

The 2-bromoaniline and the NaNO₂ and the KI are all used stoichiometrically in a 1 to 1 ratio.0746

In that case, we are looking for which of these have the smallest number of mol.0752

That is what is going to determine the mol of product, we call that the theoretical yield.0758

I only had 18 mmol of the 2-bromoaniline.0765

I have 28 mmol and then 22 mmol.0768

These guys are in excess. We are not going to run out of these before we ran out of the 2-bromoaniline.0772

This is the number, we are going to take this.0781

This is our limiting reagent.0784

This is our limiting reagent because it is the smallest number.0790

We are going to take that and we are going to copy that number down here to the mol of product0793

because that is the maximum amount of product I can get.0800

If every single molecule of the 2-bromoaniline gets converted to product, the most I can get is 18 mmol.0803

Now we know how many mol of product we can get.0812

We can use that to calculate the amount that we have.0818

Before we get there, I want to talk about this last column, the molar equivalents.0825

What we are going to do, now that we have identified the limiting reagent,0830

we are going to describe that reagent as being 1.0 equivalent.0833

We are going to describe all the other reagents with respect to that.0840

You know, compared to the 1.0 as a molar ratio.0846

What we are going to do is we are going to divide all the molar amounts by that limiting reagent molar amount to see what we have.0849

First of all, we can see that if we have exactly one equivalent of the 2-bromoaniline,0856

that will give us exactly one equivalent of our product.0861

But we see that we have an excess of the NaNO₂.0864

If we take 0.028 and we divide that by the limiting reagent amount 0.018,0867

then that comes out to 1.6 equivalent of NaNO₂.0876

In other words, there is a 60% excess of NaNO₂ is used.0884

We wanted to make sure that we used up all the 2-bromoaniline possible,0894

so we threw an extra amount of the sodium nitrite, and we use a 60% excess.0899

We can put here 1.6.0904

You want to make sure you have at least 1 to 2 decimal points here.0907

Because sometimes you have just maybe a 10% excess or maybe even a just a 5% excess.0911

You want to go out as many decimal points as possible,0917

to see whether not you have exactly one equivalent or maybe you do have a little in excess.0920

We could do the same thing for the potassium iodide.0926

If we divide the 22mmol by the 18mmol, we get 1.2.0930

We have 1.2 equivalents of KI, that has a smaller excess, smaller amount of that.0937

But still an excess amount, there are some KI leftover but not quite as much.0944

We just say a 20% excess of KI is used.0948

What is nice about these equivalents is you can look very quickly at this table.0955

Rather than looking at all these complicated molar numbers which are very tiny numbers0962

and try to figure out what is the ratio of these numbers,0967

now you can look at this very quickly and say I used twice as much of the sodium nitrite.0971

Maybe I used 10 equivalent, maybe I use a very slight excess 1.2 equivalent.0976

This column is very nice, specially if you want to scale up the reaction0981

or someone else is going to do the reaction at a different scale.0986

Then, they can just use this to say however much 2-bromoaniline,0989

I need 1.6 times that many mol of the NaNO₂, and so on.0993

The last thing that we had figure out here is our theoretical yield.1002

That is how much product can we expect, what is the maximum amount of product we can expect?1006

We already know that number in terms of mol.1011

But in the end of the day, we are going to have our product in our round bottom flask and we are going to weigh it.1014

We are going to find out how many grams we have of that.1019

Or maybe by volume, we will find out what volume we have of that.1020

We need to calculate that.1024

We are going to use that molar amount to calculate this number.1026

We are going to have to include units in that because, remember, this amounts column,1030

just putting in number 6 here does not mean anything as that 6.1036

Kilograms is that 6.1040

Liters is that 6, ml, include the units there.1042

How do we do that?1046

We know we are expecting 0.018 mol of the 2-iodobromobenzene.1047

That is the amount that we can make and we know that every 1mol of the 2-iodobromobenzene weighs 263g.1063

I’m sorry, 283g.1075

Our mol cancel, when we do that math we get 5.1g of product is our theoretically yield.1078

That is the maximum amount of product we can get.1085

We are going to put that in this table here.1088

If we wanted, we can use the density to convert that to volume and get that in volume,1093

if you are going to maybe measure it with a graduated cylinder or something.1102

Mass is usually the way that we measure how much we have of something.1105

Once the reaction is over, we can come back to our reagent table and we can find out what our actual yield is.1115

We call that the percent yield of the reaction.1121

Now that I have run the reaction, I have isolated my 2-iodobromobenzene.1124

I have purified it, I now have it in my flask.1129

Now I can report how successful is my reaction.1133

How much of my product did I get, compared to the theoretically yield that I was expecting, the maximum amount.1137

Let us say we ran the reaction, let us say we isolated 4.3g of product.1143

If we isolated 4.3g of product, what is the percent yield that we will report for that reaction?1156

We very simply take the actual yield in grams and divide it by the theoretical yield, and we convert it to a percentage.1161

It is quite a simple description there.1170

4.3 g is the actual, 5.1g was the theoretical.1175

When I do that math, I get 0.843 as my decimal number.1180

By multiplying that by 100%, it converts that to a percentage, in a yield form.1187

We get 84.3.1194

Now again, significant figures, to go beyond, you need the three here.1196

Just saying 84% yield is probably reasonable but certainly not saying 84.3215.1201

Those are not significant numbers.1207

This will tell you I was expecting the most that I could have gotten was 5g, but again, at 84% yield.1210

Most reactions do not go to 100%.1216

Even if they do, by the time you isolate and purify your product, some is lost along the way.1218

It is very difficult to get a reaction where you actually get a quantitative yield of the product1223

and get 100% yield of the product.1227

Whatever you get is what you report.1231

You do not want to try and make up a number thinking that this does not look so good.1233

A lot of times we will find, a typical student yield for a given reactions, maybe 60%.1237

It is okay if you get a number like that.1243

You just want to make sure you are reporting the actual yield of whatever your actual yield is.1245

Hopefully this helps, you get an idea of how to calculate your reagent table.1249

Definitely pay attention to how your particular instructor wants the reagent table set up.1254

But given that, hopefully, you have gone through the calculations that will help you successfully navigate it1259

and successfully calculate the numbers you need to calculate.1264

Good luck with your reactions.1267

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