Name:_____________ (4 points) Chemistry 114 First Hour Exam Remember- Show all work for partial credit. Each problem is worth 12 points. 1. Below are four compounds. For each compound: A.) Write a Lewis structure. B.) Give the geometry around the central atom, and. C.) Give the hybridization of the central atom. Note: I am skipping lone pairs on the outside atoms and overall charge on ions POCl3 (P is central) XeF4 tetrahedral electron geometry sp3 ClO3 tetrahedral electron geometry sp3 Octahedral electron geometry D2sp3 ClO4-- tetrahedral electron geometry Sp3 2. A. Explain how you get probonding and antibonding ó bonds when you hybridze s orbitals together. This works much better with a diagram. When you hybridize orbitals by adding s orbitals from two atoms together, the electron density increases between the atoms and this increased electron density holds the atoms together and creates the pro-bonding orbital. When you hybridize by subtracting s orbitasl from each other, the electron density decreases between the atoms so the hybridized electron density does not have any electron density between the atoms to hold them together, so you create an antibonding orbital. B. When we use molecular orbital theory to predict the orbitals in Be2, why do we ignore the 1s orbitals and only hybridize the 2s orbitals? The 1s orbitals are smaller than the 2s orbitals, so they do not overlap. If they do not overlap, they cannot hybridize to form bonds. 3. Below are some ionic diatomic molecules that may or may not exist. Show the ladder of filled and unfilled molecular orbitals then use this diagram to answer the following questions: A.) What is the bond order for this compound?. B.) Which compound is the most stable? The least stable? C.) Is this compound attracted to, or repelled from, a magnetic field? CN+ 89 89 89 89 OFó*2p ð*2p ó2p ð2p ó*2s ó2s 89 89 89 89 89 89 89 BO = (6-2)/2 = 2 Most stable diamagnetic - repelled BN2+ ó*2p ð*2p ð2p ó2p ó*2s ó2s 8 8 89 89 (8-6)/2=1 Least stable diamagnetic - repelled ó*2p ð*2p ó2p ð2p ó*2s ó2s (4-2)/2=1 Least stable Paramagnetic Attracted 4. Below is the structure of Ibuprophen (Advil). A. Complete the Lewis structure by showing all lone pairs of electrons. 2 lone pairs on both oxygens B. How many atoms in this structure are sp, sp2 and sp3 hybridized? Sp = 0 sp2 7 C’s or 8 total sp3 6 C’s pr 7 total C. How many ó and how many ð bonds are there in this structure? 33 ó bonds (1 in every bond) 4 ð bonds (1 in every double bond) 5. Below are the names of 4 organic compounds. Draw the structure corresponding to these names. The name I gave you may not be correct. If the name is wrong, give the correct name for this compound. Cis-2-methyl-3-ethylbutane 3,4-difluorocyclohexane 2,3-Dimethylpentane 1,2-Dibromofluorohexane 2-sec-butylpropanal methylethylketone 2,3-dimethylpentanal 2-butanone 6. Below is the structure of a hydrocarbon. Predict what will happen to this compound when it is reacted under the following conditions: 1. Cl2 and ultraviolet light 2. H2 with a Pt catalyst 3. CH3Cl with AlCl3 catalyst 7. Proteins, carbohydrates and nucleic acids are the three major biopolymers found in your body. For each of these biopolymers give: The name of the monomer unit... Amino acid Simple sugar or polysaccharide nucleotide A rough structure of the monomer units... Phosphate-Ribose - Base The main functional groups on the monomer... Amines Carboxylic Acid Alcohols aldehyde or ketone Phosphate Alcohols and aldehydes or Ketones Amines in rings 8. Auto air conditioning units currently use the hydrofluorocarbon HFC-134a as a refrigerant. (1,1,1,2-tetrafluoroethane) But it has a global warming potential 1,340 times greater than CO2, Because of this, it will be banned in Europe in this year. One alternative that has been proposed is HFO -1234yf (2,3,3,3-tetrafluoropropene) which has a global warming potential only 4 x worse than CO2. Draw the structure of these two compounds: 1,1,1,2-tetrafluoroethane 2,3,3,3-tetrafluoropropene