just do the lab and fill the blank spaces. when part 1 is complete please send it by 3pm today and finish part 2 by tomorrow 3pm. if you have any questions text me.
CHEM 131L Principles of Chemistry I Laboratory 1 Bonding and Molecular Geometries Remote Instruction Version In today’s laboratory activity, you will be using an online simulation to investigate the structure of several molecules. The shapes of molecules are predicted by VSEPR (valence shell electron pair repulsion) theory, which states that electron groups are positioned as far from one another as possible in a molecule. The electron groups considered by the VSEPR theory can be either in the form of lone pairs of electrons, or shared electrons in a chemical bond. The following shapes are predicted by VSEPR: Two electron groups Two bonding pairs: linear Three electron groups Three bonding pairs: trigonal planar Two bonding pairs, one lone pair: bent Four electron groups Four bonding pairs: tetrahedral Three bonding pairs, one lone pair: trigonal pyramidal Two bonding pairs, two lone pairs: bent Five electron groups Five bonding pairs: trigonal bipyramidal Four bonding pairs, one lone pair: see-saw Three bonding pairs, two lone pairs: t-shape Two bonding pairs, three lone pairs: linear Six electron groups Six bonding pairs: octahedral Five bonding pairs, one lone pair: square pyramidal Four bonding pairs, two lone pairs: square planar Valence bond theory states that when electron groups are positioned around an atom, they are placed in hybridized atomic orbitals. That is, rather than filling in s, p, d, or f orbitals, they occupy orbitals that are combinations of those simpler atomic orbitals. The number of atomic orbitals used in hybridization is equal to the number of electron groups around the atom. For example, in ammonia, the central nitrogen atom is bonded to three hydrogen atoms and has a single lone pair of electrons. According to VSEPR theory, the shape of ammonia is trigonal pyramidal, and according to valence bond theory, the nitrogen is sp3 hybridized since it uses its 2s and all three 2p orbitals in bonding. 2 The PhET Molecule Shapes simulation provides three-dimensional models of several small molecules as well as a set of generic models that illustrate the possible geometries of the theory. Each model can be moved and manipulated. In Part I of the worksheet, you will use the simulation together with your understanding of Lewis structures to complete the following entries. In Part II of the experiment, you will use Lewis theory to evaluate the shapes of larger molecules. Part I: Small molecules Use the PhET Molecule Shapes simulation to answer the following questions. You can find it at https://phet.colorado.edu/sims/html/molecule-shapes/latest/molecule-shapes_en.html. NOTE: Not all of the following molecules are included in the PhET Molecule Shapes simulation. If the molecule is not in the simulation, use your knowledge of Lewis, VSEPR, and hybridization theories to help you answer the questions. H2O Name: Lewis Structure: 3-D Sketch: Hybridization: Polarity: Molecular Shape: Bond Angle: NH3 Name: Lewis Structure: 3-D Sketch: Hybridization: Polarity: Molecular Shape: Bond Angle: https://phet.colorado.edu/sims/html/molecule-shapes/latest/molecule-shapes_en.html 3 CO2 Name: Lewis Structure: 3-D Sketch: Hybridization: Polarity: Molecular Shape: Bond Angle: BF3 Name: Lewis Structure: 3-D Sketch: Hybridization: Polarity: Molecular Shape: Bond Angle: ClF3 Name: Lewis Structure: 3-D Sketch: Hybridization: Polarity: Molecular Shape: Bond Angle: 4 SF6 Name: Lewis Structure: 3-D Sketch: Hybridization: Polarity: Molecular Shape: Bond Angle: O3 Name: Ozone Lewis Structure: 3-D Sketch: Hybridization: Polarity: Molecular Shape: Bond Angle: AsF5 Name: Lewis Structure: 3-D Sketch: Hybridization: Polarity: Molecular Shape: Bond Angle: 5 KrCl4 Name: Lewis Structure: 3-D Sketch: Hybridization: Polarity: Molecular Shape: Bond Angle: SeCl4 Name: Lewis Structure: 3-D Sketch: Hybridization: Polarity: Molecular Shape: Bond Angle: CH2Cl2 Name: Dichloromethane Lewis Structure: 3-D Sketch: Hybridization: Polarity: Molecular Shape: Bond Angle: 6 Find two molecules from the worksheet above that are bent, but with different hybridizations: ____________________________________ Do the two bent molecules have the same bond angle? __________________ Why? ______________________________________________________________________________ ___________________________________________________________________________________ Compare H2O, NH3, and CH2Cl2. Which has the smallest bond angle? __________________________ Why? ______________________________________________________________________________ ___________________________________________________________________________________ Part II: Larger molecules Answer the following questions about the geometry of larger molecules. You do not need the PhET simulations. Alanine is one of the simplest and most common amino acids. The structure of alanine is: C C C O O H H H H N H H H structural formula ball-and-stick model 1. Label each internal atom in the structure above with its hybridization and molecular geometry. 2. How many sigma bonds and how many pi bonds are present in alanine? ______________σ, ______________ π 7 Cyclohexane, C6H12, and benzene, C6H6, are both molecules containing six carbon atoms arranged in a ring. Draw the Lewis structures of the two molecules: Cyclohexane Benzene 3. What are the hybridizations of the carbon atoms in each of the molecules? Cyclohexane: ______________ Benzene: ______________ 4. What are the C-C-C bond angles in each of the molecules? Cyclohexane: ______________ Benzene: ______________ 5. Which of these molecules is likely to be entirely in one plane? ______________ 6. How many sigma bonds and how many pi bonds are in each molecule? Benzene: ______________σ, ______________ π Cyclohexane: ______________σ, ______________ π Name_2: Lewis Structure_2: 3D Sketch_2: Hybridization_2: Polarity_2: Molecular Shape_2: Bond Angle_2: Name_3: Lewis Structure_3: 3D Sketch_3: Hybridization_3: Polarity_3: Molecular Shape_3: Bond Angle_3: Name_4: Lewis Structure_4: 3D Sketch_4: Hybridization_4: Polarity_4: Molecular Shape_4: Bond Angle_4: Name_5: Lewis Structure_5: 3D Sketch_5: Hybridization_5: Polarity_5: Molecular Shape_5: Bond Angle_5: Name_6: Lewis Structure_6: 3D Sketch_6: Hybridization_6: Polarity_6: Molecular Shape_6: Bond Angle_6: Lewis Structure_7: 3D Sketch_7: Hybridization_7: Polarity_7: Molecular Shape_7: Bond Angle_7: Name_7: Lewis Structure_8: 3D Sketch_8: Hybridization_8: Polarity_8: Molecular Shape_8: Bond Angle_8: Name_8: Lewis Structure_9: 3D Sketch_9: Hybridization_9: Polarity_9: Molecular Shape_9: Bond Angle_9: Name_9: Lewis Structure_10: 3D Sketch_10: Hybridization_10: Polarity_10: Molecular Shape_10: Bond Angle_10: Lewis Structure_11: 3D Sketch_11: Hybridization_11: Polarity_11: Molecular Shape_11: Bond Angle_11: Find two molecules from the worksheet above that are bent but with different hybridizations: Do the two bent molecules have the same bond angle: Why: Compare H2O NH3 and CH2Cl2 Which has the smallest bond angle: Why_2: How many sigma bonds and how many pi bonds are present in alanine: fill_9: Cyclohexane: Benzene: Cyclohexane_2: Benzene_2: Cyclohexane_3: Benzene_3: Which of these molecules is likely to be entirely in one plane: Benzene_4: fill_7: Cyclohexane_4: fill_9_2: C3: O: N: C1: C2: