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Gre4nikov [31]
3 years ago
14

Describe the development of the modern periodic table

Chemistry
1 answer:
Simora [160]3 years ago
8 0
There had been new discoveries of chemicals that have been added to the periodic table in recent years
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Determine if each of the following statements about chiral molecules is True or False and select the best answer from the dropdo
oee [108]

Answer:

See explanation

Explanation:

-)<u> True or False: All R stereocenters are dextrorotatory. </u>

The absolute configuration is based is in specific rules that are not related to the ability to deflect polarized light. <u>FALSE</u>

-)<u> True or False: Chiral centers in organic molecules will have 4 different groups attached to a carbon. </u>

<u />

A chiral carbon by definition is a carbon with 4 groups. <u>TRUE</u>

-)<u> True or False: A racemic mixture has an optical activity of 0. </u>

In a racemic mixture, we have equal amounts of enantiomers, and this cancels out the optical activity. <u>TRUE</u>

-)<u> True or False: Normal linear amines can be chiral centers. </u>

<u />

In primary amines, we have 2 hydrogens. Therefore all the groups can not be different. So, is <u>TRUE</u>

<u />

-)<u>True or False: Compound C has an optical activity of 0. </u>

<u />

We need to know the structure of the compound

<u />

-)<u>True or False: If the R isomer of a molecule has an optical rotation of + 25.7 degree then the S isomer of the molecule will have an optical rotation of -25.7 degree. </u>

<u />

If we have the exact opposite (as we have in this case) the magnitud of the optical activity value will remain and the sign will change. <u>TRUE</u>

-)<u>True or False: A CN is a higher priority than a CH2OH. </u>

<u />

In this case, a carbon is directly bonded to the chiral carbon. The carbon on CN is bonded to a nitrogen atom and the carbon on CH2OH is bonded to an oxygen. So, the CH2OH will have more priority because O has a higher atomic number. <u>FALSE</u>

<u />

-)<u>True or False: All molecules with chiral centers are optically active. </u>

<u />

We can have for example mesocompounds in which the optical activity is canceled out due to symmetry planes. <u>FALSE</u>

<u />

-)<u>True or False: To have an enantiomer a molecule must have at least two chiral centers. </u>

<u />

A pair of enantiomers is made between at least 1 chiral carbon. Enantiomer R and enantiomer S. <u>FALSE</u>

<u />

-)<u>True or False: Chiral molecules are always optically active. </u>

<u />

We can have racemic mixtures or mesocompounds with chiral carbons but without optical activity. <u>FALSE</u>

<u />

-)<u>True or False: A CH2CH2Br is higher priority than a CH2F. </u>

The "Br" atom is bonded in the third carbon (respect to the chiral carbon) and the "F" atom is bonded to the second carbon. Therefore CH2F has more priority than CH2CH2Br. <u>FALSE</u>

-)<u>True or False: Meso molecules with two stereocenters have a R,S configuration. </u>

<u />

On the compounds with R and S configuration at the same time can have symmetry planes so, we will not have optical activity. <u>TRUE</u>

<u />

<u>True or False: Diastereomers have the same physical properties except in a chiral environment. </u>

<u />

All diastereomers have the same physical properties. <u>TRUE</u>

<u />

<u>True or False: Compound H has an optical activity of 0. </u>

<u />

We have to have the structure of the compound.

<u />

<u>True or False: A C=C double bond is higher priority than a -CH(CH3)2.</u>

<u />

In the case of C=C, we can say that is equivalent to two carbon bonds without hydrogens. Therefore C=C has higher priority. <u>TRUE</u>

<u />

6 0
3 years ago
You have a volumetric flask containing 0.54 M HBr. The SOLUTE is HBr and the SOLVENT is water.
soldi70 [24.7K]

Answer:

false

Explanation:

6 0
3 years ago
Firewood burns and ashes remain<br><br> is it a chemical or physical change?
erastova [34]
It is a physical change because you can not put it back like it was
4 0
3 years ago
Read 2 more answers
What does it mean to truly love someone?​
Minchanka [31]

Truly loving someone means caring for them in the ways that they need to be cared for, with no strings attached. (That's why they call it unconditional love.)

6 0
2 years ago
Deuterium is the isotope of hydrogen of mass number 2, with a proton and a neutron in its nucleus. The chemistry of deuterium is
s344n2d4d5 [400]

Answer:

True

Explanation:

We know that the zero-point-energy of a C-D system is quite lower than the zero point energy of the C-H bond so the C-D bond is stronger.

Kinetic isotope effect refers to the change in the rate of reaction owing to a change of one of the atoms of the reactants by replacing it with one of its isotopes.

Since we know that the C-D bond is stronger than the C-H bond, when we replace hydrogen with deuterium in a reaction's rate determining step we experience a little lag in the rate of reaction. This is referred to as the kinetic isotope effect in physical organic chemistry.

6 0
3 years ago
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