CHEM 114 Final Exam

• A 0.465g sample of an unknown compound occuples 245ml at 298 K and 1.22 atm. What is the molar mass of the unknown compound?

  38.0g/mol
• A large balloon is initially filled to a volume of 25.0 L at 353 K and a pressure of 2575 mm Hg. What volume of gas will the balloon contain at 1.35 atm and 253 k?

  45.0L
• A mixture of 1.0 mol He and 1.0 mol Ne are at STP in a rigid container. Which of the following statements is TRUE?

  Both gases have the same average kinetic energy
• A gas mixture is made up of four gases, the partial pressures of the individual gases are:

  N2-201 mmHg;

  O2-355 mmHg;

  CH4-270 mmHg;

  H2O-180 mmHg

  What is the total pressure of this gas mixture?

  1.32
• Consider a container of gas under a particular P, V, T set of conditions. Describe how the pressure would change if the volume were doubled while the absolute temperature was increasing by a factor of two.

  Pressure would not change
• Determine the density of NH_{3} gas at 435 K and 1.00 atm

  0.477
• Determine the volume of H2S (at 375 K and 1.20 atm) needed to produce 55.0 g of S. Assume that there is excess SO2 present.

  29.3L
• Given the equation C_{2}*H_{6}(g) + O_{2}(g) -> C*O_{2}(g) + H_{2}*O(g) (not balanced), determine the number of liters of O_{2} consumed at STP when 270.0 grams of C_{2}*H_{6} is burned.

  706L
• How much energy is required to heat 36.0 g H2O from a liquid at 65°C to a gas at 115°C? The following physical data may be useful.

  ΔHvap = 40.7 kJ/molCliq = 4.18 J/g°/sup*CCgas = 2.01 J/g°/sup*CCsol = 2.09 J/g°/sup*CTmelting = 0°/sup*CTboiling = 100°/sup*C

  87.7
• How much energy is required to vaporize 48.7 g of dichloromethane (CH2Cl2) at its boiling point, if its AHvap is 31.6 kJ/mol

  18.1kJ
• Identify the characteristics of a gas

  Indefinite shape and volume
• Identify the compound that does not have hydrogen bonding

  (CH3)_3N
• If 2.0 mol of gas A is mixed with 1.0 mol of gas B to give a total pressure of 1.6 atm, what is the partial pressure of gas A and B?

  PA = 1.06 atm and PB = 0.53 atm
• If a sample of 0.29 moles of Ar occupies 3.8 L under certain conditions, what volume will 0.66 moles occupy under the same conditions?

  8.6L
• Place the following substances in order of decreasing boiling point

  H2O>CO>N2
• The boiling point of H2O is much higher than that of the analogous molecule H2S. This is mostly due to

  hydrogen bonding much stronger in H2O than in H2S
• The forces between polar molecules is known as

  Dipole-dipole forces
• The total pressure of a gas mixture is the sun of the partial pressure of its components is known as

  Dalton’s law
• The volume of a gas is proportional to number of moles of a gas is known as

  Avogadro’s law
• The volume of a gas is proportional to the temperature of a gas is known as

  Charlie’s Law
• To what temperature must a balloon, initially at 25*C and 2.00L be heated in order to have a volume of 6.00 L?

  894K
• What is the strongest type of intermolecular force present in NH2CH3?

  Hydrogen Bonding
• What mass of NO2 is contained in a 13.0L tank at 4.58 atm and 385K

  86.7g
• What volume (in mL) will a sample of F_2 gas occupy in a syringe at 5.5 atm, if the F_2 has a volume of 25.0 at 1.2 atm?

  5.5mL
• The crossing of what in a phase diagram represents the phase change from a gas to a solid?

  Sublimation curve
• Which of the following gases has the largest density at STP?

  F2
• Which phases of matter present at the triple point?

  Solid, liquid, and gas
• Which of the following will cause the volume of an ideal gas to triple in value?

  Lowering the pressure by a factor of 3 while the temperature stays constant
• Which one of the following has definite shape and volume?

  solid
• Which one of the following has a low density?

  Gas
• Which substance below has the strongest intermolecular forces?

  A2X, Hvap=39.6 kJ/mol
• A compound is found to have a molar mass of 598 g/mol. If 35.8 mg of the compound dissolved in enough water to make 175 ml of solution at 25 degrees C what is the osmotic pressure of the resulting solution ?

  6.36 torr
• A reaction occurs via the following sequence of elementary steps. What is the reaction intermediate? 1st step

  C
• A solution containing less than the equilibrium amount is called

  An unsaturated solution
• A solution is formed at room temperature by vigorously dissolving enough of the solid solute so that some solid remains at the bottom of the solution.Which statement below is TRUE?

  The solution is considered saturated
• Which equation best describes how changes in temperature will impact the rate of reaction?

  Arrhenius Eqn.
• A solution is prepared by dissolving 98.6 g of NaCl in enough water to form 875 mL of solution. Calculate the mass % of the solution if the density of the solution is 1.06g / m * L

  10.6%
• A student makes a solution containing 125g of acetonitrile (CH3CN) and 300g of water. What is the mol fraction of acetonitrile?

  0.155
• At a given temperature the vapor pressures of benzene and toluene are 183 mm Hg and 59.2 mm Hg, respectively. Calculate the total vapor pressure over a solution of benzene and toluene with Xbenzene = 0. 580.

  131mmHg
• Commercial grade HCI solutions are typically 39.0% (by mass) HCI in water. Determine the molality of the HCI, if the solution has a density of 1.2g/m L

  17.5m