Ask Chemistry Expert

A center of chirality (from the Greek cheir, hand) imparts the property of handedness to a molecule. In this part of the experiment, the left- or right- handedness of molecules with a chiral center will be illustrated with models.

A molecule is said to be chiral (that is, to have the property of handedness) if its mirror image is not superimposable. The mirror image of a left hand, for example, is a right hand. A molecule that is achiral has a mirror image that is superimposible. We shall see that any molecule with a plane of symmetry is achiral.

Procedure: Reconstruct the original model (carbon (black) with light blue ball, red, blue and, green polyhedrons attached). Set the model on the desktop so that the substituent light blue ball atom points toward the ceiling.

Looking down on the model and proceeding clockwise from the green atom, record the colors of the three atoms that rest on the desktop.

Now construct a second model that is the mirror image of the first, and place it on the desktop with the light blue ball atom up:

6. In which direction, clockwise or counterclockwise, must you proceed in order to list the same sequence of colors of the three atoms resting on the desk's surface?

a. Clockwise

b. Counterclockwise

Try to superimpose the two models.

7. The models are

a. Superimposable

b. Not superimposable

The two models that you have just constructed represent chiral molecules- they lack a plane of symmetry and have mirror images that are notsuperimposable. Two substances, the molecular structures of which are related as an object and its nonsuperimposable mirror image are called enantiomers. They differ from each other only in properties that have a direction or "handedness," such as, for example, the direction(clockwise or counterclockwise) in which they rotate a beam of plane-polarized light. Because of this latter property, such substances are sometimes called optical isomers. They are optically active.

Now we will examine the consequence of having at least two identical atoms or groups attached to a tetrahedral carbon atom.

Replace the green atom in each model with a red atom, so that each model has two identical groups attached to the central carbon atom:

8. Are the models still mirror images?

a. Yes

b. No

9. Does either of the models have a plane of symmetry?

a. Yes

b. No

10. Are the models superimposable?

a. Yes

b. No

11. Do the models represent identical molecules or different molecules?

a. Identical

b. Different

Place each model on the desk so that the light blue ball substituent points up.

12. To define the same sequence of colors for the three atoms resting on the desk top, must you proceed

a. Clockwise

b. Counterclockwise

c. Either way

13. Are the models chiral (handed)?

a. Yes

b. No

The models you have just studied represent achiral molecules. Their mirror images are identical. They are optically inactive. Any molecule that has a plane of symmetry is achiral.

Chemistry, Academics

  • Category:- Chemistry
  • Reference No.:- M9462011

Have any Question?


Related Questions in Chemistry

Question 1bonding energyi draw an energy level diagram for

Question 1: Bonding Energy i. Draw an energy level diagram for a single Na ion and Cl ion. ii. Explain what is happening to the energy level between these two ions in terms of the Potential Energy. iii. Which process uti ...

Wat is the molarity to the hundredths place of 50 g hpo3

What is the molarity, to the hundredths place, of 5.0 g HPO3 in 300. mL of solution?

Describe how to assign anbspoxidation number from

Describe how to assign a Oxidation number from the text: The oxidation number of an atom in an elemental substance is zero. The oxidation number of a monatomic ion is equal to the ion's charge. Oxidation numbers for comm ...

How many grams of h2so4 must be dissolved into 0709 l of

How many grams of H2SO4 must be dissolved into 0.709 L of solution to generate a concentration of 0.303 M?

What could a source of error be during a titration lab that

What could a source of error be during a titration lab that is not a humans fault?

How many moles of magnesium ion are present in 525g

How many moles of magnesium ion are present in 5.25g Mg 3 (PO 4 ) 2 ?

What is the volume of a solution with a concentration of 12

What is the volume of a solution with a concentration of 1.2 M that contains 12 g of NaOH?

What is the molarity of a solution made by dissolving 200 g

What is the molarity of a solution made by dissolving 20.0 g of CrCl2 in 0.150 L of solution?

What is the mass of naoh present in grams given that a 100

What is the mass of NaOH present in grams, given that a 100. mL solution has a concentration of 0.125 M?

What is the volume of a solution in milliliters that

What is the volume of a solution, in milliliters, that contains 1.5 g LiNO3 and has a concentration of 0.40 M?

  • 4,153,160 Questions Asked
  • 13,132 Experts
  • 2,558,936 Questions Answered

Ask Experts for help!!

Looking for Assignment Help?

Start excelling in your Courses, Get help with Assignment

Write us your full requirement for evaluation and you will receive response within 20 minutes turnaround time.

Ask Now Help with Problems, Get a Best Answer

Why might a bank avoid the use of interest rate swaps even

Why might a bank avoid the use of interest rate swaps, even when the institution is exposed to significant interest rate

Describe the difference between zero coupon bonds and

Describe the difference between zero coupon bonds and coupon bonds. Under what conditions will a coupon bond sell at a p

Compute the present value of an annuity of 880 per year

Compute the present value of an annuity of $ 880 per year for 16 years, given a discount rate of 6 percent per annum. As

Compute the present value of an 1150 payment made in ten

Compute the present value of an $1,150 payment made in ten years when the discount rate is 12 percent. (Do not round int

Compute the present value of an annuity of 699 per year

Compute the present value of an annuity of $ 699 per year for 19 years, given a discount rate of 6 percent per annum. As