DOUBLE BOND EQUIVALENTS or INDEX NUMBER:
It is a numerical value on the basis of which we can have an idea about the different type of equivalent structures we can have for a given formula.
Knowing the DBE the problems on structural isomerism can be more easily solved.
Mathematically,
DBE= {( n(v-2))/2}+1
where n is the number of atoms
v is the valency of the atom.
Eg 1):
Consider C4H6
DBE={4(4-2)/2+6(1-2)/2}+1
={(8-6)/2}+1
=2
This implies that the molecule may contain,
1)two double bonds or one triple bond.
2)one ring and one double bond.
3)two rings.
Thus by knowing the DBE total number of structural isomers can be formulated.
Eg 2):
Consider C3H6O
DBE={3(4-2)/2+6(1-2)/2+1(2-2)/2}+1
=1
So the isomers may contain either a double bond or a ring.
I hope this is helpful!
The same way you calculate the molecular mass of any compound. Alternatively, if you know the mass of one isomer, you don't need to do any calculations. All isomers having the same formula have the same mass.
You double the haploid number.
We can find atomic mass and mass number in chemical elements. Atomic mass is about weight of the atom. Mass number is about total of neutrons and protons.
To find the total number of electrons in an element, first you need to look up the element's atomic number. That number tells you how many protons are in the element. Then, look up the net charge of the element. The number of protons subtracted by the elements net charge will give you the number of its electrons.
We can find atomic mass and mass number in chemical elements. Atomic mass is about weight of the atom. Mass number is about total of neutrons and protons.
Information about isomers can be found in all chemistry text books. Isomers are compounds which have the same molecular layout but have a different structure.
The same way you calculate the molecular mass of any compound. Alternatively, if you know the mass of one isomer, you don't need to do any calculations. All isomers having the same formula have the same mass.
11
find it urself fool
====== Answer 1: ----------- proportion... A portion of the total is to its percentage of the total as the total is to 100%.
You find the total number of outcomes by adding the first part of the odds to the second part of the odds. For example: 1:1 The total number of outcomes would be 2. To find the ratio of equally likely outcomes to the total number, find the number of outcomes, and put it on the left of the semicolon. Then put the total number on the right side. For the same example: (outcomes)->1:2<-(total)
The total number of protons.
Number of total marks x100
You have to divide the number of questions you answered correctly of the number of total questions then multiply by 100. (#correct over total#of questions) x 100 Or, you divided 100 by the total number of questions, then multiply by the number you got right to find your percentage.
You double the haploid number.
Divide the total price by the total number of units.
add the total number of scores