6. Below is given the unit cell for an ionic species containing iron and sulfur. Using this unit cell, determine how many mols of this iron sulfide are present in 7.34 g of the solid.

7. The formula C3H8O has three isomers (let’s call them A, B, and C) in which no ring structures are present and the carbons are saturated (each carbon has four single bonds within the structure). Liquid forms of A and B have similar surface tension and viscosity values, whereas a liquid form of C has a lower value for these two properties. From this observation, determine plausible condensed formulas for each isomer. Hint: you may not be able to assign a letter to each individual isomer. Give a brief justification of your answer. 8. Below is shown a vapor pressure visualization of a liquid at a point where a physical equilibrium has been established. The grey rectangle at the bottom represents the liquid and the number of spheres present represents the amount of vaporized particles at physical equilibrium. Use this to answer the questions that follow.

a) Draw a vapor pressure visualization of this substance if the temperature was to be increased. Give a brief justification of your drawing. Hint: there is more than one correct answer, only supply one plausible drawing. b) Draw a vapor pressure visualization of this substance if the external pressure inside the box was decreased. Give a brief justification of your drawing. Hint: there is more than one correct answer, only supply one plausible drawing.

b) How many 125 mL mineral spritz can he make using a fifth of Campari? A fifth is defined as 750 mL. Hint: use your answer from part a as the molarity of each mineral spritz made. c) Let’s say he wants to make a 125 mL mineral spritz that is 1.0 M ethanol. What volume of Campari and Pellegrino are required? d) Campari gets its dark red color from the naturally occurring dye carmine, which has an absorption λmax at 500 nm with ε = 0.09244 M−1 cm−1. Because he is a nerd and had some spare time, Dr. McKeachie prepared several mineral spritz as shown in the table below. Complete the table, using the “pure” form of the Beer-Lambert law (A = ε I C; no “+ error” and I = pathlength) for “expected absorbance.” Assume he will use a 1.00 cm cuvette.

Spritz contents [ethanol] expected absorbance @ 500 nm (1) Campari only

(2) 90. mL Campari; 100. mL water (3) 68 mL Campari; 100. mL water (4) 45 mL Campari; 100. mL water (5) 23 mL Campari; 100. mL water

(6) 100. mL water e) An “unknown mineral spritz” has been prepared by dumping random amounts of Campari and Pellegrino together until the total volume is 250. mL. This solution gives an absorbance of 0.246 at 500 nm in a 1.00 cm cuvette. What volume of Campari and Pellegrino were used? Let’s make this easier and assume the absorbance of the unknown is the same as the expected absorbance from the Beer-Lambert Law (again, no “+ error”). f) On special occasions, Dr. McKeachie will make a “champagne spritz” where he replaces mineral water with sparkling wine. Assuming a typical California sparking wine is 2.1 M in ethanol, what is [ethanol] in a champagne spritz? 13. 8.99 g of CHCl3 (chloroform) are mixed with water, and this solution has a final volume of 194 mL. The solution’s density is 1.03 g/mL. Determine the mass percent, mol fraction, molarity and molality of chloroform this solution. You may assume the density of water is 1.000 g/mL. 14. What is the expected vapor pressure of the solution created in #13, in atm, at 29 °C? The vapor pressure of pure water is 30. mm Hg at 29 °C and the vapor pressure of pure chloroform at 29 °C is 110 Torr. 15. Let’s say the vapor pressure of the solution created in #13 is measured as 0.466 psi. Are positive or negative deviations to Raoult’s Law occurring? Does this match what you would expect, given the components of this solution?

16. Determine the boiling and freezing point of the solution created in #13, in °C. 17. More water is added to the solution created in #13, and the osmotic pressure at 37 °C of the new solution is measured as 5.52 atm. How many mL of water were added to the original solution? 18. A small amount of sodium sulfide has been added to 47 g of water. This sample of water is observed to boil at 100.759 °C. What mass of sodium sulfide was placed in the water?