CHEM 1C Midterm 2

Does tetrahedral have geometric isomers?

No! Regardless of how you organize, the bond angles do not change

Can tetrahedral be optically active?

Yes! If the central atom is bonded to 4 different things, then it is chiral

Geometric isomers

different in positions (cis/trans) (subset of stereoisomers) \n - cis = ligands are side-by-side or at 90° angle \n - trans = ligands are across from each other at 180° angle

Linkage isomers

different binding sites (subset of structural isomers)

Coordination isomers

different atoms inside the complex ion

Optical isomers

nonsuperimposable mirror images

for unidentate ligands: if pair of the same thing \[(aa)\] or a repeating pair \[(ab)(ab)\], then it does not have optical isomers. If each pair is unique, then it has optical isomers

for bidentate ligands: Look at the axis of symmetry (which does not spilt the bidentate ligands). If symmetrical, it does not have optical isomers. If it is not symmetrical, it has optical isomers

the cis or trans version can exhibit different optical isomerism, as in one could be optically active which one is not, vive-versa, neither, or both

Chiral

molecule with nonsuperimposable mirror image

optical isomerism

achiral

superimposable mirror images

does not exhibit optical isomerism

Alkane reactions

**combustion reactions:** CₙH₂ₙ₊₂ + (3n + 1)/2 O₂ + n CO₂ + (n+1) H₂O

**halogenation reactions:** CH₄ + Cl₂ → CH₃Cl + HCl

**dehydrogenation reactions:** saturated hydrocarbon (CnH2n+2) → unsaturated hydrocarbon w/ double bond (CnH2n) + H2

Ketoses

carbohydrate with ketone group, usually C2

What is boiling point elevation caused by?

The nonvolatile solute decreases the vapor pressure, effectively increasing the boiling point

What is a monosaccharide?\`

a simple sugar with multiple OH groups

disaccharides are two of these and polysaccharides are a polymerized chain of these (which lowers the osmotic effects (M decrease)

Protein structures

Primary: amino acids linked by amide (peptide) bonds (H-N-C=O)

Secondary: Short term structure. Alpha helix and Beta (Pleated) sheet

Tertiary: Long term structure, 3D. Dictated by intermolecular forces and R groups finding those similar to them.

How do you identify condensation polymerization?

Check for amide bond (H-N-C=O) created by a carboxylic acid and amine or an ester link (R1-(O=C)-O-R2) created by a carboxylic acid and an alcohol

How do proteins form?

A condensation reaction between amino acids, where the amino group of one bonds with the carboxyl group of another to form an amide (peptide) bond

H-N-C=O

Amino Acid structure?

C bonded to an H, an amino group, an R group, and a carboxyl group

How do esters form?

A condensation reaction between a carboxylic acid and an alcohol to form an ester link

What is an ether?

R1-O-R2

Tonicity

hypertonic - one solution has a higher concentration of solute than another (water in cells, causing to swell and burst) (BAD!)

isotonic - both solutions have the same concentrations of solute (saline bags)

hypotonic - one solution has a lower concentration of solute than another (BAD!)

carboxylic acid

R-(C=O)-OH

Can H-bond with itself and water

Most soluble in water

Higher BP than alcohol

Synthesis of a carboxylic acid

Oxidizing a primary acid

OR oxidizing an aldehyde

Aldoses

Sugar with an aldehyde group at the end

freezing point depression

the solvent is diluted by the addition of a solute, so that fewer molecules are available to freeze, causing the freezing point to decrease

Paramagnetic vs Diamagetic

Paramagnetic: unpaired electrons

Diamagnetic: all paired up

Nucleotides

5 Carbon sugar

Nucleobase (base with N)

Phosphate group

Link by ester bonding (sugar base of one and phosphate group of another)

Colligative Properties

depend on how much is present, not on what is present

Aldehydes

H-(C=O)-R

Cannnot hydrogen bond with itself

Amines

C-N single bond

Primary: 1 substituent

R1-NH2

Secondary: 2 substituents

R1-NH-R2

Tertiary: 3 substitutents

3 Rs bonded to N

Carbohydrates

CH2O

Ketone

C doubled bonded to an O and 2 R groups

Synthesis: oxidize a secondary alcohol

The two R groups cannot be Hs, they must be carbon chains to be a ketone

Can tetrahedrals be low spin?

Tetrahedral is ALWAYS high spin

An R group can start with…

Really, anything. It is mainly Carbons, but an R group can be just an H, or halogens.

The only exception is ketones, where the two R groups must be carbon chains and cannot be just an H (that would be an aldehyde).

Can Square Planar be chiral?

NO! ALWAYS ACHIRAL

can have geometric isomers

Can Tetrahedral be chiral?

YES! IF IT HAS 4 DIFFERENT BONDS

Can Tetrahedral have geometric isomers?

NO! NO CHANGE IN BOND ANGLE NO MATTER WHAT YOU DO

Which octahedral configurations has geometric isomerism?

\[M(a)4(b)2\] (1 cis, 1 trans)

\[M(a)3(b)3\]

Which square planar configurations have geometric isomerism?

\[M(a)2(b)2\] (1 cis, 1 trans)

\[M(a)(b)(c)(d)\] (3 isomers: 2 cis, 1 trans)

Which tetrahedral complexes are optically active?

\[M(a)(b)(c)(d)\]

What octahedral configurations have geometric isomers?

\[M(a)5(b)\] (2 isomers)

\[M(a)3(b)2(c)\] (3 isomers)

\[M(a)3(b)3\] (2 isomers)

\[M(a)3(b)(c)(d)\] (4 isomers)

\[M(a)2(b)2(c)2\] (5 isomers)

What octahedral configurations are optically active?

\[M(a)3(b)(c)(d)\]

\[M(a)2(b)2(c)2\]