Chemistry Questions

1) A direct change of state from solid directly to gas without going through the liquid phase is called ? (3 pts.) 2) Which state of matter has a high density and a definite volume? (3 pts.) 3) Which state of matter has a low density and is easily compressed? (4 pts.) 4) The change of a substance from a liquid to a gaseous form is called: (4 pts.) 5) Is Evaporation an Endothermic or Exothermic Process? (4 pts.) /18 6) What Type of Molecules experience dipole-dipole Attractive Forces? (4 pts.) 7) Which intermolecular forces are found in CC142 (4 pts.) 8) How many kJ of heat are needed to completely vaporize 3.30 moles of H2 O? The heat of vaporization for water at the boiling point is 40.6 kJ/mole. (5 pts) 9) A 250-gram sample of water at the boiling point had 45.01 kJ of heat added. How many grams of water were vaporized? Heat of vaporization for water is 40.6 kJ/mole. (5 pts) 10) How many kJ of heat are needed to completely melt 17.3 g of H2O, given that the water is at its melting point? The heat of fusion for water is 6.02 kJ/mole. (5 pts) /23 11) Calculate the mass percent of a NaCl solution prepared by mixing 47.0 g NaCl with 125.0 mL of pure water. (density of water is 1.0 g/mL) (5 pts) 12) Calculate the molarity of a KCI solution prepared by dissolving 0.525 moles of KCI in 250. mL of water. (5 pts.) 13) Calculate the molarity of a KCI solution made by dissolving 24.7 g of KCI in a total volume of 500. mL (5 pts) 14) What is the final concentration (M) of a solution prepared by diluting 50.0 mL of a 6.00 M KCI solution to a volume of 0.500 L? (5 pts) /20 15) Given that the freezing point depression constant for water is 1.86°C kg/mol, calculate the change in freezing point for a 0.907 m sugar solution. (5 pts) 16) What is the change in the boiling point of a solution made by dissolving 14.7 g of C6H12O6 into 150.0 ml of water? The density of water is 1.00 g/mLand Kb =0.512°C/m (5 pts) 17) What is the concentration of H+ in solution given the [OH-] = 2.54 x 10-4, (4 pts.) 18) What is the pH of a solution that has a [H*1 = 0.0045 M? (5 pts) 19) What is the pH of a solution that has a [OH"]=0.0033M (5 pts) 20) What is the concentration of H+ in a solution with pH = 2.50? (5 pts) 21) A solution at 25°C has a hydrogen ion concentration of 2.6 x 10-5 M. Is this solution acidic, basic or neutral? (4 pts.) 22) What are the values of the followings in neutral solution: pH (2 pts) [OH]] = (2 pts) [H+] = (2 pts) /20