C125 STUDY GUIDE EXAM QUESTIONS AND ANSWERS

C125 STUDY GUIDE EXAM QUESTIONS AND ANSWERS electron delocalization - Answer- Resonance structures lower the energy through.... sp3 - Answer- What is the hybridization of the central atom in H2O? yes - Answer- can both bonding and antibonding molecular orbitals have nodal planes? perpendicular to internuclear axis - Answer- sigma and pi antibonding molecular orbitals always have a nodal plane where? 2p - Answer- If we apply the HOMO and LUMO concepts in atomic orbitals, we will have HOAO (Highest Occupied Atomic Orbitals) and LUAO (Lowest Unoccupied Atomic Orbitals). What is the HOAO of O atom? -1 - Answer- Draw the best Lewis structure of N2O. What is the formal charge of O? trigonal bipyramidal - Answer- What is the electron geometry of SF4? 120 - Answer- what is the bond angle in BF3 false - Answer- N=N-O and N=O=N are resonance structures to each other. T or F? sp3 hybrid orbital - Answer- In the Lewis structure of NH3, there is one lone pair on N atom. What orbital will this lone pair on N reside? 0.044 - Answer- If a Fe stock solution has a concentration of 1.1 mg/mL, what is the concentration when 2 mL of this stock solution is diluted to 50. mL? Keep 2 sig figs for the answer. 0.33 - Answer- What is the absorbance if the % transmittance is 47%? Keep 2 sig figs for the answer. L/(mol*cm) - Answer- A=ebc, where A is absorbance, which is unit-less, b is path length that is 1 cm for the cuvette used. If the concentration c uses mol/L, what unit should the extinction coefficient e have? complexing agent was occupied by excess amount of H+ and didn't complex w/ Fe, some Fe was lost during transfers b/w glassware, under-digestion of cereal - Answer- The Total Cereal has a Fe concentration of 0.6 g Fe per g of Cereal. However, it is very common for students to get less than 0.6. Which of the following can be contributors to this lower experimental result than the manufacturer listed value? There are three correct answers and find all of them.