(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.   

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.[x], 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.[x], 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:

10.  (WCSP24.[x]) Hot air is less dense than cold air and this is the reason that hot air balloons float! A hot air balloon on a cool summer morning is filled with air to a volume of 2.20 x 106 L and warmed to 195 °F (90 °C).  A hot air balloon must be inflated to a volume of approximately 2.60 x 106  L in order to float in air. a. (4 points) At constant pressure, provide a molecular-level explanation of the relationship between temperature and volume of a gas.   b.  (6 points) Calculate the temperature the gas must be (in °C) in order to float.   Enter the temperature below