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

13. (3 points) Draw a 3D Lewis structure (use wedge and dash bonds) for CH2S.  Be sure to include any formal charges or lone pairs.  WCSP[x] a. (2 points) Determine the electron domain geometry about the carbon. __________________________ b. (2 points) Is CH2S polar? Explain in just a few words.     Enter the number of lone pair electrons in the box below.   

(WCSP24)  Select the intermolecular force(s) that are present in: LiNO3 in H2O

(WCSP24) When 5.0 g of CaCl2 is dissolved in 25 g of solution, the temperature of the solution increases by 25  ̊C.  Select all of the statements that are true of this process.  

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

8.  Write the balanced chemical reaction for limestone (CaCO3) reacting with acid rain (H2SO4).  Include the phases (s, l, g, aq). (WCSP[x], 4 points) Enter the coefficients for each reactant and product in the box below (no spaces)

14. A phase diagram for a substance with a molar mass of 60.1 g/mol is shown below. (WCSP[x]) a. (6 points) Sketch the heating curve for the substance going from -30 °C to 150 °C (point A to point B on the diagram above).  A template is given below. b. (6 points) Calculate the heat required to vaporize 30 g of the substance initially at room temperature (25 ºC). (WCSP[x]) ΔHfus 5.4 kJ/mol ΔHvap 45.1 kJ/mol Cs (solid) 2.45 J/g°C Cs (liquid) 2.26 J/g°C Cs (gas) 2.05 J/g°C Melting point -89.5 °C Boiling point 82.6 °C   Enter the value in the box below.   

6.  You have likely heard of the weed killer Round Up.  It is a solution of glyphosate in water.   To prepare a solution for application, you need to do a dilution of the concentrate so that the final concentration of glyphosate is 0.45 M (equivalent to a 5% glyphosate). Calculate the volume of 2.8 M Round Up concentrate needed to make 1 gallon (3.875 L) of 0.45 M weed killer for yard and garden application. (WCSP[x], 6 points) Enter the value in the box below.   

4.  (WCSP24.[x], 8 points) Cell phones use electromagnetic radiation with an energy of about 1.08 J/mol of photons.   Calculate the wavelength (in nm) and frequency that can be used to describe light with this energy. Enter the wavelength in nm below.

16. Carbon monoxide is a toxic gas.  The upper limit of carbon monoxide (CO) in air is 9 ppm (9.0 x 10-6) over an 8-hour period.  a. At this concentration, how many moles of CO are there in a bedroom with a volume of 29,000 L at 25 oC and 0.98 atm? (3 points, WCSP[x]) b. How many molecules of CO are in the room? (3 points, WCSP[x])   Enter the value from part a in the box below.