Ch 14 Test Review Questions #14-18

14. What types of intermolecular forces are acting on the liquid state of each of the following substances, and why?

            a. N₂                                     London Dispersion Forces                Nonpolar Molecule

            b. NH₃                         H-Bonding                     polar/H with FON  

                                        

            c. He                            London Dispersion Forces                Noble Gas/single atom

            d. CO₂                         LDF                                                    Nonpolar Molecule

15. List the type of crystalline solid formed by each of the following substances, and list the intermolecular or intramolecular force that forms the solid.

            a. NH₄NO₃                  ionic crystal                            no intermolecular to speak of

            b. CO₂                                 molecule                                 London Dispersion Force

            c. iron                           atomic/metallic                       no intermolecular to speak of

            d. cesium fluoride          ionic                                        no intermolecular to speak of

16. What is the relationship between vapor pressure and boiling point?

            When the vapor pressure is equal to the atmospheric pressure, that temperature will be the boiling point

17.  What are 3 things that affect vapor pressure and boiling point?

            type of intermolecular force, temperature and atmospheric pressure

18. Draw a heating and cooling curve for each of the following examples and list only the steps to get the total energy. Use the Standards Reference Sheet. (Heating curve is on next page)

            a. Calculate the energy required to melt 8.5 g of ice at 0°C. 

                                    Only one step Q=m

            b. Calculate the energy required to heat 25 g of liquid water from 25°C to 100°C and

    change it to steam at 100°C.

                        1st step:      Q=c_pmΔT

                   2nd step:     Q=mΔH_vap

                   Add up answers               

c. Calculate the total energy required to melt 15 g of ice at 0°C, heat the water to 100°C,

    and vaporize it to steam at 100°C.

                        1^st step:       Q=mΔH_fus

                                2nd step:     Q=c_pmΔT

                   3rd step:     Q=m

                   Add up the answers