Chapter 10. Can You draw the Lewis structure for a given covalently bonded molecule?

Transcription

1 Chapter 10 Can You draw the Lewis structure for a given covalently bonded molecule? e.g. SF 6 and CH 3 Cl 2. identify and count the number of non-bonding and bonding domains within a given covalently bonded molecule? Predict Bond Angles too!!!! (I added this one!!) e.g., Based on the Lewis structure, the number of nonbonding domains in the O 3 molecule is e.g., The bond angle in Cl 2 O is expected to be approximately a. 90 degrees b degrees c. 120 degrees d. 145 degrees e. 180 degrees 3. predict the shape of the molecule based on VSEPR (that is, draw the Lewis structure and identify bonding and non-bonding domains...then use the tables relating total domains and bonding/non-bonding domains)? [note: for a test, you'll have to know the names of the different shapes possible] e.g., Application of the concepts of VSEPR theory leads us to conclude that the shape of the SO 3 molecule is 4. use the shape of the molecule to predict whether the molecule will be polar (have a dipole) or not? e.g, Which of the following molecules CO 2, CS 2, NO 2, COS is/are polar? a. NO 2 only b. CS 2, NO 2, and COS c. CO 2 only d. COS and NO 2 e. COS only 5. explain what "VB" theory is?

2 e.g., Bonding in the chlorine molecule can be explained by the valence bond theory in terms of an overlap between a. the 1s orbital of a chlorine and the 1s orbital of the other chlorine b. the 2s orbital of a chlorine and the 2s orbital of the other chlorine c. the 2p orbital of a chlorine and the 2p orbital of the other chlorine d. the 3s orbital of a chlorine and the 3s orbital of the other chlorine e. the 3p orbital of a chlorine and the 3p orbital of the other chlorine 6. predict what type of hybrid orbitals are used based on molecule shape e.g., Draw a Lewis structure for the C 2 H 6 molecule. What is the hybrid orbital set used by either of the carbon s for bonding? e.g., The PCl 3 molecule employs hybrid orbitals centered on the phosphorus in its bonding scheme, according to valence bond theory. What is the name of the hybrid orbital set used by the phosphorus in this molecule? Can You use the combined gas law? Chapter 11 A sample of a gas was isolated in a gas containment bulb on a manifold used in this type work. The volume of the bulb was liters. The temperature was o C, and the manifold pressure was torr. What volume, in liters, would this gas sample occupy at STP? 2. show how the combined gas law is a result of the three separate gas laws (Boyle's, Charles', and Gay-Lussac's)? Well can you?!! 3. rub your belly and pat yourself on the head simultaneously (just kidding...seeing if you actually read this!)? Hmmmm faster now!!!

3 4. use the ideal gas law (PV=nRT) to solve for a missing variable? A gas sample occupies a volume of liters when the temperature is 35.2 o C and the pressure is torr. How many moles of gas are there in the sample? 5. use the ideal gas law in stoichiometric problems? How many liters of pure oxygen gas, measured at 45.2 o C and kpa, are required for the complete combustion of 5.60 liters of acetaldehyde gas (C 2 H 4 O), measured under the same conditions of temperature and pressure? Hey RECALL LIMITING REACTANTS ON THIS ONE! The reaction, MnO 2 (s) + 4 HCl(aq) MnCl 2 (aq) + Cl 2 (g) + H 2 O(l) was being studied g of MnO 2 were reacted with 70.0 ml of 2.50 M HCl solution. The chlorine produced was collected in a vessel. The pressure measured atm at a temperature of 78.2 o C. Determine the volume of chlorine produced if the theoretical yield was obtained. 6. use Dalton's Law of Partial Pressures to find the pressure exerted by one gas in a mixture of gases? e.g., What is the total pressure exerted by a gaseous mixture that consists of 1.00 g of hydrogen and 8.00 g of neon in a 2.80 liter container maintained at o C? 7. calculate mole fractions? What is the mole fraction of hydrogen in a gaseous mixture that consists of 8.00 g of hydrogen and g of neon in a 3.50 liter container maintained at o C? 8. use the fact that at STP, 1 mol of any gas occupies 22.4 L? What volume would 11.2 g of a gaseous compound occupy at STP if the molecular weight of the compound is 44.0 g/mole and the substance behaves as an ideal gas?! a. 5.6 liters b liters c liters d liters e liters 9. describe effusion and diffusion and use Graham's law of effusion to relate the rates of effusion of 2 gases to the molecular masses of those two masses.

4 The average speed at which a nitrogen molecule effuses at 30.0 o C is 480 meters per second. The average speed at which a butene molecule (C 4 H 8 ) effuses at this same temperature should then be 10. recite and describe the postulates of the Kinetic Theory of Gases? Give me a really difficult one!!! 11. differentiate between a real gas and an ideal gas? Go one, you can do it! 12. convert a given pressure unit into another pressure unit? A special shipping container for compressed gas is rated at x 10 3 kpa. This rating can be expressed in kilobars (kbar) as 13. describe the use of a manometer and a barometer? See your book you need to read at least one section of it!! 14. explain 'collection over water' (what apparatus is used, what is the total pressure equal to, why use this apparatus in the first place)? A sample of methane gas (CH 4 ) was collected by downward displacement of water ( over water ) in a gas collection flask. The total pressure in the collection flask was measured as torr, the temperature was 25.0 o C, and the measured volume of gas in the flask was ml. How many grams should the methane weigh? At 25.0 o C, the vapor pressure of water is 23.8 torr.

5 Chapter 12 Can You Explain all the intermolecular attractions? 2. Explain some of the general properties of liquids and solids (compressibility, diffusion, volume and shape, surface tension, ease of evaporation (e.g., boiling point), etc) and how intermolecular attractions determine these properties? 3. Explain "dynamic equilibrium" and predict what will happen to a system under equilibrium that is perturbed or disturbed (Le Chatelier's Principle)? 4. Explain vapor pressure and the factors which it depends upon? 5. Explain "normal boiling point" and how intermolecular forces affect it? 6. Explain "phase diagrams" and locate/discribed the critical point, critical temperature and critical pressure (also, what is a supercritical fluid?)? 7. Given two molecules, predict which will have the higher boiling point, vapor pressure, viscosity, surface tension? HERE ARE SOME TYPICAL QUESTIONS I MAY ASK: Which one of the following molecules is most polarizable, and subject to significant instantaneous dipole-induced dipole forces? a. H 3 C Br b. H 3 C Cl c. H 3 C F d. H 3 C H

6 e. H 3 C I Which one of the following covalent compounds will exhibit hydrogen bonding in the liquid state? a. CH 2 F 2 b. Cl 2 NH c. H 2 PCl d. HBr e. NCl 3 Which compound is expected to exhibit hydrogen bonding forces? a. CH 3 CH 2 H b. CH 3 CH 2 O H c. CH 3 CH 2 PH 2 d. CH 3 CH 2 S H e. CH 3 CH 2 Se H The property that measures or describes the magnitude of resistance to flow in a liquid is called a. London forces b. malleability c. surface tension d. vapor pressure e. viscosity When a liquid undergoes a phase change to a gas, the process is called a. condensation b. deposition c. fusion d. sublimation e. evaporation Which one of the following listed compounds should have the lowest vapor pressure at a given temperature at which all these substances are in the liquid state? a. CH 3 CH 2 F b. CH 3 CH 2 CH 3 c. CH 3 CH 2 CH 2 CH 3 d. CH 3 CH 2 O H e. CH 3 O CH 3 The vapor pressure of a liquid increases with increasing temperature. The temperature at which this vapor pressure is equal to the prevailing outside atmospheric pressure is a. the boiling point b. the flash point c. the vaporization point

7 d. 100 o C e. the normal boiling point Given the following substances and their normal boiling points, in o C: C: 43.8 o C D: 93.7 o C M: 56.7 o C T: 83.5 o C R: 63.6 o C Which set below correctly lists some of these liquids in order of increasing intermolecular forces at 20 o C? a. C < R < D b. D < T < R c. R < T < C d. C < D < M e. D < R < M P a b e * * d 51. At the temperature and pressure of point d, which statement below is true? phase. c T a. The substance will sublime. b. There will be an equilibrium between the solid phase and the gaseous c. Vaporization and deposition will take place simultaneously. d. Condensation and evaporation will take place simultaneously. e. The substance will be a superfluid.