Complete Question:
check the first image for complete part of the question
Answer and Explanation:
Epoxide is a three membered ring made up of two carbon atoms and one oxygen atom. Epoxides are cyclic ethers. Due to its ring size, it is highly strained and very reactive. Epoxide ring opening takes place with respect to addition of acid and base.
Ring opening of epoxide with acid:
In the presence of base, the nucleophile attacks the epoxide ring at more substituted site and inverse stereochemistry takes place.(check file 2 attached)
Ring opening of epoxide with base:
The backside attack of nucleophile takes place in less substituted site and then it undergoes protonation to form a product.
(check file 2 attached)
Answer:
Metals on the left of the Periodic Table.
Non-Metals on the top-right, plus Hydrogen.
To know this you pretty much do have to kind of memorize a few electronegativities. I don't recall ever getting a table of electronegativities on an exam.
From the structure, you have:
I remember the following electronegativities most because they are fairly patterned:
EN
H
=
2.1
EN
C
=
2.5
EN
N
=
3.0
EN
O
=
3.5
EN
F
=
4.0
EN
Cl
=
3.5
Notice how carbon through fluorine go in increments of
~
0.5
. I believe Pauling made it that way when he determined electronegativities in the '30s.
Δ
EN
C
−
Cl
=
1.0
Δ
EN
C
−
H
=
0.4
Δ
EN
C
−
C
=
0.0
Δ
EN
C
−
O
=
1.0
Δ
EN
O
−
H
=
1.4
So naturally, with the greatest electronegativity difference of
4.0
−
2.5
=
1.5
, the
C
−
F
bond is most polar, i.e. that bond's electron distribution is the most drawn towards the more electronegative compound as compared to the rest.
When the electron distribution is polarized and drawn towards a more electronegative atom, the less electronegative atom has to move inwards because its nucleus was previously favorably attracted to the electrons from the other atom.
That means generally, the greater the electronegativity difference between two atoms is, the shorter you can expect the bond to be, insofar as the electronegative atom is the same size as another comparable electronegative atom.
However, examining actual data, we would see that on average, in conditions without other bond polarizations occuring:
r
C
−
Cl
≈
177 pm
r
C
−
C
≈
154 pm
r
C
−
O
≈
143 pm
r
C
−
F
≈
135 pm
r
C
−
H
≈
109 pm
r
O
−
H
≈
96 pm
So it is not necessarily the least electronegativity difference that gives the longest bond.
Therefore, you cannot simply consider electronegativity. Examining the radii of the atoms, you should notice that chlorine is the biggest atom in the compound.
r
Cl
≈
79 pm
r
C
≈
70 pm
r
H
≈
53 pm
r
O
≈
60 pm
So assuming the answer is truly
C
−
C
, what would have to hold true is that:
The
C
−
F
bond polarization makes the carbon more electropositive (which is true).
The now more electropositive carbon wishes to attract bonding pairs from chlorine closer, thereby shortening the
C
−
Cl
bond, and potentially the
C
−
H
bond (which is probably true).
The shortening of the
C
−
Cl
bond is somehow enough to be shorter than the
C
−
C
bond (this is debatable).
Answer:
see notes below
Explanation:
The mole is the mass of substance containing 1 Avogadro's Number of particles. That is, 1 mole substance = 1 formula weight. For elements, 1 mole weight is equal to the atomic weight expressed as grams. For molecules, 1 mole weight is equal to the molecular weight expressed as grams.
1 mole = 1 formula weight
<u>Moles to Grams and Grams to Moles</u>
Grams => Moles
Given grams, moles = mass given / formula weight
*Ask the question => How many formula weights are there in the given mass? => Results is always moles.
Moles => Grams
Given moles, grams = moles given X formula weight
*Summary
Grams to Moles => divide by formula weight
Moles to Grams => multiply by formula weight
Answer:
50
Explanation:
If you want a percent as a decimal so you can divide you must make it a decimal for example in your case it would be like this, 0.05, then all you do is divide 1,000 by 0.05
