Chem 112 Exam 1Questions With Elaborated Answers

Definition of Polar Covalent Bond - correct answers difference in electronegativity Which of the Molecules are Polar ? CCl4, NH3, NO3-, H2, C3H8, H2O - correct answers NH3, H2O, ( C3H8=?) Which of the salts would have highest FA assuming distance are same ? ( NaI, CaSO4, AlPO4) - correct answers AlPO4 what is used to measure the Ion/Dipole "Glue " - correct answers Enthalpy of Hydration = amount of energy given off when the ion is surrounded by water molecules ( Strongest = MOST neg) Hydrogen Bonding - correct answers Special Dipole -Dipole case = NOF = Dipole - Induced Dipole - correct answers polar molecule influences a non polar molecule to act polar EX: water and O2 The ______ a molecule, the easier it is is to induce a dipole - correct answers The ____larger____ a molecule, the easier it is is to induce a dipole Which of the molecules would have the lowest Δ H v a p - CH3OH, C2H6, C4H10 - correct answers C2H6 Molarity - correct answers Moles of Solute / L of SOLUTION Mole Fraction - correct answers mol of solute / ( mol of solute + moles of solvent ) molality - correct answers solute (mol) / SOLVENT ( kg) change in freezing/ boiling pt - correct answers = Van't Hoff Factor * Kfp/bp * molality of solute ion-ion, hydrogen bond, ion- dipole, dipole-dipole, IND-IND, ion - IND, dipole-IND - correct answers ion-ion ( ionic bond) , hydrogen bond ( NOF) , ion- dipole ( salt and water/de association) , dipole-dipole ( polar) , IND-IND, ion - IND ( ion + non polar) , dipole-IND ( polar + non polar) What type(s) of intermolecular forces are expected between two NH3 molecules? - correct answers dipole- dipole, IND-IND, HB, dipole-IND What type(s) of intermolecular forces are expected between a water molecule and HCl? - correct answers (hydrogen bond, dipole- dipole, IND-IND , )dipole-IND, ion-IND What type(s) of intermolecular forces are expected between two methanol (CHOH) molecules? - correct answers hydrogen bond, IND-IND, dipole-dipole, dipole-IND what decides HIGH Vapor Pressure ? - correct answers WEAKER IMFs & LOW molar mass ( high vapor pressure = low bp) what decides HIGH heat of vaporization? - correct answers STRONGER IMFs & higher molar mass The normal boiling point is the temperature at which the vapor pressure is ______________ - correct answers 1 atm or 760 mm Hg OR external pressure is given what are units for pressure when finding Vapor Pressure - correct answers mmHg what is the van't Hoff factor of the ionic compound CH3COONa? - correct answers TWO: Na+ and CH3COO- What is the expected van't Hoff factor of the ionic compound K3PO4? - correct answers FOUR: 3 K+ cations and 1 PO43- Temp of freezing point or boiling point - correct answers Temp of freezing point or boiling point = i * Kfp or Kbp * MoLALity of solute Freezing Point and Boiling Point relationship to mi - correct answers lowest freezing point= highest mi Highest Boiling point = Highest mi units for rate constant - correct answers 1/Mses ---make sure the k units and the time units match up units for the concentration when using rate law - correct answers M ( molarity ) what order is radioactive decay ? - correct answers FIRST ORDER what is The activation energy Ea - correct answers activated complex - the reactants In the Arrhenius equation, what is A? - correct answers A= y-int = frequency factor rate determining step. - correct answers The one slow step in the mechanism Molecular iodine would be most soluble in: - correct answers a non polar substance At room temperature, F2 and Cl2 are gases, Br2 is a liquid, and I2 is a solid. This is because: - correct answers dispersion interactions increase with molecular size. The reason that CCl4 has a higher boiling point than CF4 is that: - correct answers CCl4 molecules have a greater polarizability For a given substance, which of the following phase transitions should RELEASE the most energy. - correct answers Gas to solid