Rank the following ionic solids in order of increasing melting points.  (WCSP24)

(WCSP24) Lactic acid is responsible for muscle soreness after exercise.  a.  What is the molecular formula of lactic acid? CHO b. How many sigma and pi bonds are present in the structure? σ: π:

12. The balanced combustion reaction for methane or natural gas, a fuel used in home heating, is shown below: CH4 (g)       +       2 O2 (g) 

(WCSP24) Fill in the following table with the appropriate number of protons, neutrons, and electrons (enter a number only).     Protons Neutrons Electrons 84Rb+1 35Cl-

5.  Ice cream begins as a solution of milk, sugar, and stabilizers. This liquid mixture is pasteurized at high temperature (72 oC) to kill any harmful bacteria. The pasteurized solution is cooled, flavors are added, and then it is placed in a “hardening room” (at -38 oC) to freeze.   Cs (solid) = 3.10 J/g·K Cs (liquid) = 1.60 J/g·K ΔHfus = 186 J/g a. (WCSP24., 5 points) Draw the cooling curve for ice cream beginning as a liquid at 72 oC to solid at -38 oC. The freezing point of ice cream is -3 oC.  Label the axes with temperature values. (Blank graph given below.))   b.  (WCSP24., 8 points) Calculate how much heat (in kJ) must be removed from a ½ gallon (912 g) of Bittersweet Mint when it cools from 72 oC to -38 oC.   Enter the heat lost from the ice cream below:

(WCSP24)  Select the appropriate word that completes each sentence. a.  Intermolecular forces occur molecules. b. When intermolecular interactions are formed, energy is c. Freezing is d. The energy absorbed when ice (water solid) melts is than the energy absorbed when water (liquid) vaporizes e. The

10.  The ocean is said to contain one hundred trillion million dollars of gold (Au) in the form of gold(III) chloride.  For decades, chemists (and wannabes) have attempted to precipitate gold from seawater, albeit unsuccessfully.  One method would be to form an insoluble gold salt. Then, by a redox reaction, reduce the gold ions to pure gold ($$$!). (WCSP)   a.  In theory, sodium hydroxide could be used to precipitate gold from seawater.  Write the net ionic equation for the reaction below. Start with the complete ionic equation and identify spectators. (6 points)  AuCl3(aq)    +   3 NaOH (aq)

8. (WCSP24.) Heavy metals, such as calcium, can be extracted from water by a precipitation reaction.   Hard water has a Ca2+ ion concentration around 4.24 x 10-3 M.   When hard water is mixed with a solution of soda ash (sodium carbonate, Na2CO3), the calcium ions react to form a precipitate and the water is now “softened.”  The precipitate can be removed by filtration. a.  (8 points) Write the complete balanced equation and the net ionic equation that occurs when Ca2+ and sodium carbonate react. Circle the precipitate. b.  (6 points) A 1000 mL soda ash solution was prepared with 5.0 g of sodium carbonate (MW = 106 g/mol).  Calculate the concentration (in M) of the sodium carbonate in the solution.  Calculate the concentration of sodium ions Enter the concentration of sodium ions below.

For which of the following reactions would ΔHf = ΔHrxn for the formation of HCl? (WCSP24)  

Recall the Scheduling Min Lateness problem. Define lateness of a task as max(0, finish time – due date). T/F: The earliest due date first algorithm produces the optimal solution when we want to minimize the sum of the lateness of the tasks instead of the maximum.