Exam Review. Chapters

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Emery Horton
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1 Exam Review Chapters

2 Chapter 13 Solutions Concepts of: Solution definitions and representations on the macroscopic and particle level Intermolecular forces Concentration units Solubility and temperature Solubility and pressure Colligative properties Non electrolytes Electrolytes

3 1. What does a saturated, unsaturated and super saturated look like on a macroscopic level and particle level? Refer to lecture notes 2. What is the solubility between the substances: a. water and chlorine partially b. water and dichloromethane (CH 2 Cl 2 ) soluble c. chlorine and carbon tetrachloride soluble d. magnesium chloride and carbon tetrachloride insoluble e. magnesium chloride and water soluble

4 1. What the intermolecular between the substances: a. water and chlorine dispersion and dipole induced dipole forces b. water and dichloromethane (CH 2 Cl 2 ) dispersion and dipole dipole forces c. chlorine and carbon tetrachloride dispersion d. magnesium chloride and carbon tetrachloride dispersion and ion induced dipole forces e. magnesium chloride and water dispersion and ion dipole forces 2. Which substance(s) will hydrogen bond with water: fluoride ions, formaldehyde, methane, methanol, dimethyl ether, ammonia, and ammonium ions * * Ammonium ions are included because they follow the rules used here to assign this. Experimentally, there is evidence that a gas phase ammonium ion hydrogen bonds with water but for large samples, there is more evidence that ammonium ions do not. Once again, we use rules broadly in general chemistry that have many more subtle nuances that will be explored in more detail in advanced courses.

5 1. What is the molar and molal concentrations of the solutions? C 12 H 22 O 11 (aq) HCl(aq) Percent by mass 14.16% 28.0% Density g/ml g/ml Molal concentration m 10.7 m Molar concentration M 8.75 M X solute X solvent For a dilute solution of lead(ii) chloride where 1.50 mg of the salt is dissolved in 1.56 L of water, what is the concentration of lead(ii) and chloride ions in ppm? ppm (Pb 2+ ) and ppm (Cl )

6 1. The solubility of nitrogen in water at a particular temperature is 6.24x10 4 M. If the temperature of this solution is increased, what is a possible solubility of nitrogen in water? <6.24x10 4 M 2. For the aqueous solution described in number 1, the external pressure was 1 atm. What mass of nitrogen is dissolved in 575 ml of water if the pressure above the solution is increased to 5.75 atm? g Would the mass of nitrogen increase or decrease if the pressure above the solution decreased to atm? decrease (by an order of magnitude)

sodium nitrate unsaturated c. sodium sulfate saturated 2.

7 1. Using Figure 13.3, assign the solutions below as saturated or unsaturated and describe what 80.0 g of the solute at 40 o C would look like: a. potassium nitrate saturated b. sodium nitrate unsaturated c. sodium sulfate saturated 2. If the temperature of these solutions is increased to 80 o C, what mass (if any) is not in solution? Only sodium sulfate is not all in solution with roughly a mass of 45 g not in solution.

8 1. What mass (in g) of urea (CO(NH 2 ) 2 ) in g of water is needed to decrease the vapor pressure of water from mmhg of pure water to mmhg for the solution? The temperature is held constant at 40 o C g urea 2. What mass (in g) of water at 50 o C is needed to make an aqueous solution of 10.0 g urea that has a vapor pressure of mmhg if the vapor pressure of water at this temperature is mmhg g water

9 1. Assuming ethanol (CH 3 CH 2 OH) and acetone (CH 3 COCH 3 ) form an ideal solution. What is the total pressure of a 25% ethanol solution by mass at 20 o C? At 20 o C, the vapor pressure of ethanol is 41.0 mmhg and the vapor pressure of acetone is 161 mmhg. 126 mmhg 2. Of the two substances listed above, which has a higher boiling point? ethanol 3. Of the two substances, which has lower intermolecular forces? acetone

10 1. What is the boiling point of a solution made by combining 10.0 g of urea (CO(NH 2 ) 2 ) in 85.0 g of ethanol? The molal boiling point elevation constant for ethanol is 1.22 o C/m and the normal boiling point of ethanol is 78.4 o C o C 2. What is the freezing point of a solution made by combining 10.0 g of ethanol in 85.0 of water? The molar freezing point depression constant for water is 1.86 o C/m o C

11 A solution is made by dissolving 10.0 g of sodium chloride in g of water at 25 o C. The density of the solution is g/ml 1. What is the osmotic pressure of this solution? 67.4 atm 2. What is the boiling point of this solution? o C 3. What is the freezing point of this solution? 5.5 o C 4. If potassium chloride was used instead of sodium chloride, how would the previous measurements change? Assuming i measured would change only slightly, the values would all decrease due to the larger molar mass of potassium (so less number of ions because potassium is larger)

12 Chapter 14 Reaction Kinetics Concepts of: Reaction rate Measuring reaction rate Initial rates and initial concentrations The rate law and rate constants Experimental determination of rate laws First order, second order and zero order reactions Integrated rate laws Half life

13 1. What is the reaction rate if the initial concentration of A is M and the final concentration is M and the reaction occurs over 1.50 minutes? 2A 2B + C 1.67x10 2 M/min 2. What is the change in concentration of B and C for this same time period? Δ[B] = 5x10 2 M Δ[C] = 2.5x10 2 M 3. If the initial concentration of C is 0 M and the final concentration of C is M and the reaction occurs over 90 seconds, what is the reaction rate? Is this faster or slower than the first set of conditions (in number 1)? rate = 0.05 M/min this is a faster reaction

14 1. What is the rate law given the following data: 2A 2B + C rate = k[a] Experiment Initial rate (M/s) [A], M What is the rate constant? s 1 What is the reaction order? 1

15 1. What is the rate law given the following data: 2A + B Products rate = k[b] Experiment Initial rate (M/min) [A], M [B], M What is the rate constant? min 1 What is the reaction order wrt [A]? 0 What is the reaction order wrt [B]? 1 What is the reaction order overall? 1

16 1. What is the rate law given the following data: 2A + B Products rate = k [A] [B] Experiment Initial rate (M/min) [A], M [B], M What is the rate constant? M 1 x min 1 What is the reaction order wrt [A]? 1 What is the reaction order wrt [B]? 1 What is the reaction order overall? 2

Physical Properties of Solutions

Physical Properties of Solutions Physical Properties of Solutions Types of Solutions (13.1) A Molecular View of the Solution Process (13.2) Concentration Units (13.3) Effect of Temperature on Solubility