{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Handout-09_1

# Handout-09_1 - Chemistry 111 Fall 2005 Prof Simpson...

This preview shows pages 1–2. Sign up to view the full content.

Chemistry 111 Fall, 2005 Prof. Simpson Chemistry 111 Handout #9 Gas Laws, Kinetics, Thermodynamics & Thermochemistry This handout is intended as a study guide for you for Exam 3 (November 17, 2005). These questions are typical of the larger problems that will appear on the exam (e.g. the 8 – 15 point problems). My Guarantee: 50% of the points on this exam will come directly from this study guide . This guarantee does not mean the questions will be exactly the same on the exam. That is, there is no point in memorizing the numerical answers, as they will certainly be different at exam time. I will provide a key on Wednesday, November 16 so you can check over your answers and your reasoning processes. You will learn the most if you do the questions yourself first (either alone or in a group of students) and THEN ask for help or confirmation. Gas Laws. G1 . Oxygen in respiration therapy is stored in 43.0 L gas cylinders. At 20.0 o C, the pressure inside the tank is 1.50 x 10 2 atm. (a) If all of the gas was let out of the tank, how much volume would it occupy at 1.00 atm pressure and 20 o C? (b) What would the pressure inside the tank be if the temperature were doubled to 40.0 o C? (c) A patient uses 30% of the oxygen in the tank. What is the new pressure (in atm)? Assume the temperature is 20.0 o C. (d) Sketch the Boltzmann distribution of speeds for the oxygen molecules in the tank for two different temperatures T 1 and T 2 . Make sure you clearly label which curve goes with which temperature, and which temperature is higher. (e) What is the average kinetic energy per mole of the oxygen atoms in the tank originally (43.0 L, 20.0 o C, 1.50 x 10 2 atm)? (f) Does the average kinetic energy per mole increase with the process described in part (a)? What about in part (b)? What about in part (c)? Explain. G2 . A liquid hydrocarbon is found to be 16.73% H by mass. A 1.158 g vaporized sample of the hydrocarbon has a 385 mL volume at 71.0 o C and 749 mmHg. What is the molecular formula of this hydrocarbon? G3 . Consider the reaction of SO 2 and O 2 to form SO 3 : 2 SO 2 (g) + O 2 (g) Æ 2 SO 3 (g) (a) Assume this reaction is run in a constant volume container (10.0 L) in an ice bath (273 K). You start the reaction with 5.00 g SO 2 , 5.00 g O 2 and 5.00 g SO 3 in the container. What are the initial and final total pressures in the container? (b) What are the partial pressures of all three components before the reaction in (a)? (c) What are the partial pressures of all three components after the reaction in (a)? (d) Now you run a reaction under constant pressure (1.00 atm), still in the ice bath. How many liters of SO 3 gas are produced by the reaction of 6.06 L of SO 2 and 2.25 L of O 2 . G4 . How many milligrams of magnesium metal must react with excess HCl to produce 500.0 mL of H 2 gas measured at 25 o C and 2.00 atm? Mg(s) + 2 HCl (aq) Æ MgCl 2 (aq) + H 2 (g) G5 . Scandium (Sc) metal reacts with excess aqueous hydrochloric acid to produce hydrogen gas. It is found that 2.41 L of hydrogen gas, measured at 100 o C and 722 torr, are liberated by 2.25 g of Sc. Calculate the number of moles of H 2 liberated, the number of moles of Sc consumed, and write a balanced net equation for the reaction that has occurred.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}