Tham khảo sách 'chemistry part 21, julia burdge,2e (2009)', khoa học tự nhiên, hoá học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 500 CHAPTER 12 Intermolecular Forces and the Physical Properties of Liquids and Solids Additional Problems Name the kinds of attractive forces that must be overcome in order to a boil liquid ammonia b melt solid phosphorus P4 c dissolve CsI in liquid HF d melt potassium metal. Which of the following properties indicates very strong intermolecular forces in a liquid a very low surface tension b very low critical temperature c very low boiling point d very low vapor pressure At 35 C liquid HI has a higher vapor pressure than liquid HE Explain. Based on the following properties of elemental boron classify it as one of the crystalline solids discussed in Section high melting point 2300 C poor conductor of heat and electricity insoluble in water very hard substance. Referring to Figure determine the stable phase of CO2 at a 4 atm and 60 C and b atm and 20 C. Which of the following substances has the highest polarizability CH4 H2 CC14 sf6 h2s Given two complementary strands of DNA containing 100 base pairs each calculate the ratio of two separate strands to hydrogen-bonded double helix in solution at 300 K. Hint The formula for calculating this ratio is where AE is the energy difference between hydrogen-bonded double-strand DNAs and single-strand DNAs and R is the gas constant. Assume the energy of hydrogen bonds per base pair to be 10 kJ mol. The average distance between base pairs measured parallel to the axis of a DNA molecule is A. The average molar mass of a pair of nucleotides is 650 g mol. Estimate the length in centimeters of a DNA molecule of molar mass X 109 g mol. Roughly how many base pairs are contained in this molecule A CO2 fire extinguisher is located on the outside of a building in Massachusetts. During the winter months one can hear a sloshing sound when the extinguisher is gently shaken. In the summertime there is often no sound when it is shaken. Explain. Assume that .
