In this lab we use electrophilic addition of a hydrogen halide to an alkene to make 2-bromo-2-methylbutane. Electrophilic addition is an addition reaction where a pi bond is removed to create two new covalent bonds, Y-Z + C=C → Y-C-C-Z. Electrophilic addictions can also be the reverse of dehydrohalogenation. Dehydrohalogenation is when a double bond is formed between the α- and β-carbon. In this lab the addition of hydrogen bromide produces a more substituted alkyl halide with respect to Markovnikov's rule where the Bromine atom attaches to the more substituted carbon.**

**According to lab manual, www.wikipedia.com
PROCEDURE

First we mixed 25ml of hydrobromic acid and 10mlof amylene in a 50ml flask. Then we attach the apparatus and reflux the solution for 30 minutes by heating the solution until it boils, after this we allow the solution to cool down and then poured it into a125ml separatory funnel to drain and discard the lower spent acid layer. We washed the organic layer with a combination of 20ml of saturated sodium bicarbonate solution and 20ml of ether. Then we drained the lower aqueous layer and we kept the organic layer. We added 4 to 5 pellets of calcium chloride to the organic layer and allowed the solution to dry for 10 minutes. After this we placed the dry ether solution in a 50ml flask and fractionally...

...Old Dominion University
ORGANIC 214
Alkene Addition
Submitted by:
Alkene addition: Bromination of (E) Stilbene
Introduction:
In this lab we used the greener approach, which involves the addition of bromine across a double bond. When bromine reacts with E-stilbene (trans-1,2-diphenylethene), two new chiral carbons are created from the sp2 carbons, therefore 3 different dibrominated stereoisomers are possible: meso-(1R,2S), or the raceminc mixture-(1R,2R) or (1S,2S)-dibromo-1,2-diphenylethane (Gilbert, 2010). When the bromination ion intermediate proceeds through a stereospecific mechanism, then the meso dibromide is formed exclusively. The racemic dibromides are formed from the concerted syn addition if the mechanism proceeds through a carbocation.
Mechanism:
Observations:
To start this experiment, 0.200g of (E) Stilbene, white salt like compound with no specific aroma, were added to a round bottom flask weighting 17.73g. Then 4mL of cold acetic acid, clear liquid with vinegar smell, were also added to the flask and the mixture with a flea stir bar was placed in sand bath for around 12 minutes until the (E) Stilbene was completely dissolved. Pyridinium tribromide (0.394g), a bright red powder, was added to the mixture, resulting in a fast change in the coloration of the first mixture from clear to an orange/brown liquid. The new reaction was placed back to the sand bath and the dark orange color,...

...Engineering Chemistry III
Prof. K. M. Muraleedharan
Aromatic electrophilic substitution (Ar-SE) Reactions
The special reactivity of aromatic systems towards electrophiles arises mainly from two factors: the presence of π electron density above and below the plane of the ring - making it nucleophilic, and the drive to regain the aromatic character by opting for substitution as opposed to a simple addition reaction. Preference towardsaddition reactions in the case of alkenes and substitution in the case of aromatic compounds becomes evident if we analyze the energy profiles of these reactions (Figures 1 and 2).
Figure 1.
Indian Institute of Technology Madras
Engineering Chemistry III
Prof. K. M. Muraleedharan
Figure 2. Note: consider all the resonance structures of the wheland complex
The mechanism of electrophilic aromatic substitution involves an initial rate determining interaction of the π system with the electrophile to give a benzenonium ion intermediate (σcomplex or wheland complex), which undergoes a rapid de-protonation by the base in the second step to restore aromaticity (Figure 3).
E H
E H
+ E+
E H
fast
E
+ HB+
B
Figure 3. Some common electrophilic aromatic substitution reactions are: halogenation, nitration, sulfonation, Friedel-Crafts Acylation and Friedel-Crafts alkylation. These differ only in the
Indian Institute of Technology Madras...

...binary numerals.
The main interactive circuit at the top of this page is an arithmetic circuit capable of performing both addition and subtraction on any two 4-bit binary numbers. The circuit has a Mode switch that allows you to choose between adding (M=0) and subtracting (M=1). To understand why this circuit works, let’s review binary addition and binary subtraction. We use 4-bit numbers in the examples because the main interactive circuit is a 4-bit adder–subtractor.
Binary addition is certainly easier than decimal addition. You just add 0s and 1s. For example to add the numbers five (0101) and six (0110) together, we just add the respective bits:
Decimal numerals | Binary numerals |
6
+5 | 0110
+0101 |
11 | 1011 |
For binary subtraction, we use 2’s complement to keep things simple. For instance, to perform the operation six (0110) minus five (0101), we first obtain the 2’s complement of five and then add it to six:
Step one: Getting the 2’s complement of 5
1. Flip every bit in five to get 1010.
2. Add one to 1010 to get: 1010 + 1 = 1011.
Step two: Adding the 2’s complement of 5 to 6:
1.
Decimal numerals | Binary numerals |
6
+(-5) | 0110
+1011 |
1 | 10001. |
We show the carry bit in green because normally it does not count towards the result.
Design
Now that we have reviewed our binary addition and subtraction skills, let’s look at what...

...Lesson 3
Topic: Fractions
Subtopic: Addition and Subtraction of Fractions
Materials
• A set of paper strips with words written on it
• Fish bowl
Objectives
• To guess the word written on the paper strip
• To practice patience and understanding to those who can not get the answer correctly
Control of Error
• Teacher
Presentation
• The teacher will introduce the activity and give the instruction on what to do.
• She will ask for 5 pairs of volunteers from the class. One volunteer will pick a paper strip from the bowl and the other will guess the word. Then they will exchange places. If they can get the answer correctly, they will receive a prize.
Work by 4’s
Materials
• A set of fraction paper strips
• A box
Objectives
• To add similar and dissimilar fractions
• To participate actively in the activity
Control of Error
• Teacher
• Key cards
Presentation
• The class will form groups of 4 members.
• The group will discuss the steps in adding fractions.
• Each member will get 1 paper strip from the box.
• They will add the fractions on the paper strips.
• Then they will do LAS 1a – 1c.
Learning Activity Sheet 1a
Recall
Add the following fractions. Express the sum to lowest term if needed.
3/6 + 2/6
3/13 + 4/13
2/9 + 6/9
4/16 + 12/16
6/17 + 5/17
6/12 + 8/12
5/15 + 7/15
2/7 + 11/7
8/5 + 6/5
4/14 + 6/14
Learning Activity Sheet 1b
Reinforcer
Let’s solve this fraction pyramid! Add the shapes that...

...Addition and Subtraction of Integers
Addition of Positive Integers
Consider the addition of 2 + 3.
The plus sign, +, tells us to face the positive direction.
So, to evaluate 2 + 3, start at 2, face the positive direction and move 3 units forwards.
This suggests that:
Positive integers can be added like natural numbers.
Addition of Negative Integers
Consider the addition of (–2) + (–3).
The plus sign, +, tells us to face the positive direction.
So, to evaluate (–2) + (–3), start at –2, face the positive direction and move 3 units backwards.
Note:
We can write (–2) + (–3) as –2 + –3
Subtracting a Positive Integer from a Negative Integer
Consider the value of (–2) – (3).
The minus sign, –, tells us to face the negative direction.
So, to evaluate (–2) – (3), start at –2, face the negative direction and move 3 units forwards.
We notice that:
That is:
This suggests that:
Adding a negative integer is the same as subtracting a positive integer.
From the above discussion, we can state that:
Negative integer are added like natural numbers; but place a minus sign, –, in front of the sum.
Example 7
Find the value of:
Solution:
Addition of a Positive Integer and a Negative Integer
Consider the addition of 3 + (–7).
The plus sign, +, tells us to...

...Visit www.downloadmela.com for more papers
i had attended an off-campus interview of godrej. It starts on time so be on time.
it started with Box test. the question are as follows.
1) Box1
box2
box3
13
11
7
using ony addition and subtraction bring 19 in box1 and 30 in box3.
2) box1 contains Son's current age is 13 and box2 contains fathers current age is 58 box3
contain sum of father and son six yrs back.
bring father's age 13yrs before son was born in box 1 and sum of father and son after 7yrs.
3) box1-2 box2-12 box3-350
using multiplication and division only bring 74 in box 3 in 3steps
4) box 1 cotain odd value X or Y the box 2 =X i.e 7 or 12 box 3= Y has value 19 if X is 7 or
31 if x is 12 get even value X or Y Use any operator
steps allowed 3
5)69,70 or 71 in box-1 ; 18,19, or 20 in box-2 ; 60,61, or 62 in box-3
get -3 , -4 , or -5 in box-2 in 3 steps.Use all operations i.e. ( +,-,*,/ ).
6)box1-a box2-b box3-c
get 3a-2b-c in box3 using only subtract 3steps
7)box1-a box2--a box3-a-1
in 3steps using any operation get a*(a-1)-(a-1)*a in box2
8) t is the total number of sun glass sold which has c number of cartons and l loose glasses.
Each cartons contains 27 glasses. If each sale of carton, 3rs discount is awarded on each
glass. Each glass cost rs9.
Box1- total number of glass sold
box2- Cost of each glass
box3-discount on each glass
using any operation in 6 steps, bring total discount and total selling price in box2 and box3...

...Subtraction and Addition of Algebraic Expressions
Math 11
Objectives
The student should be able to:
Determine the degree of a polynomial
Identify the fundamental operations of polynomials
Definition of Terms
Algebraic expression is an expression involving constants and or variable, with all or some of the algebraic operations of addition, subtraction, division and multiplication
Definition of Terms
Components of an
Algebraic Expression
Constant term: fancy name for a number
Variable term: terms with letters
Example: 3xy – 4z + 17
Variable expression with 3 terms:
3xy, -4z, 17
2 variable terms and 1 constant term
Variable Terms
Consist of two parts
The variable(letter) part
The number part
Example:
2xy has a coefficient of 2
-6j has a coefficient of –6
W has a coefficient of 1
Definition of Terms
Monomial an algebraic expression containing only one term
ex. 4xy4
Binomial an algebraic expression containing two terms
ex. 4a + 3b
Trinomial an algebraic expression containing three terms
ex. 2a + 5b + 3c
Definition of Terms
Polynomial an algebraic expression containing two or more terms
An algebraic expression in which each term is a constant, or a constant times a positive integral power of a variable, or a constant times the product of positive integral powers of two or more variables
ex. 2x – 3y
4a3 – 2b + 5c
3x + 5
Degree of Polynomial
The degree of each...

...the Analytical or Component methods. Using each method, it was found out that Component method is the most accurate as its approach is purely theoretical, that is, all other physical factors are neglected leaving only the appropriate ones to be calculated. In addition, properties of these quantities such as associativity and commutativity of the addition operation were also explored.
1. Introduction
Vectors play an important role in many aspects of our everyday lives or of one’s daily routine. It is a mathematical quantity that has both a magnitude and direction.
A vector is what is needed to "carry" the point A to the point B; the Latin word vector means "carrier". The study of vectors had gone through a lot of revisions, starting from the 19th century where mathematicians used geometrical representations for complex numbers. Lots of changes and multiple varieties of altering were conducted to this study, which led to the discovery of the vector that we all know today. Operations on vectors are also made possible through time. Addition of vectors was clarified and can now be done in different ways. Vector addition in a graphical way can use the polygon method and the parallelogram method. Analytically, a vector addition can
be done through the use of trigonometric functions (sine, cosine, and tangent as well as their inverses) or the component method.
In our times, vectors are...