Problem 1: In the gas equation PV = nRT the meaning of n is the following:
Answers:

• number of liters
• stoichiometry
• number of cubic meters
• number of moles
• number of molecules

Problem 2: Blood pressure of a patient is 120/80 mmHg. Estimate maximal absolute pressure.
Answers:

• 1.15 atm
• 120 mmHg
• 0.16 atm
• 1.7atm

Problem 3: According to the kinetic molecular theory, only one of the following statements is true. Mark it.
Answers:

• The average momentum of particles is inversely proportional to the square root of their mass
• Individual molecules have exactly the same energy defined by the temperature
• At low pressure, the particles of gas exhibit continual random motions owing to their mutual attraction
• The heat content is a linear function of the temperature
• The average kinetic energy of the particles is directly proportional to the absolute temperature of the gas

Problem 4: The Celsius temperature in a storage room was increased from 25C to 50C. How much did the average kinetic energy of molecules in the room change? Mark the closest answer.
Answers:

• decreased in half
• increased 2^½ - fold
• increased by 8%
• the increase cannot be calculated without knowing the molecular mass
• doubled
• increased by 4.1%

Problem 5: How does the root mean square velocity, μ, of Helium (He, molecular weight = 4) relate to that of H₂ (molecular weight = 2)?
Answers:

• under standard conditions, μ is always the same
• one half of H₂ μ
• 4 times μ of H₂
• 2^-½ times μ of H₂
• 2 times μ of H₂

Problem 6: The temperature in a room was increased from 5°C to 25°C. How much did the average speed of gas molecules in the room change? Mark the closest answer.
Answers:

• increased by ~7 %
• decreased ~5-fold
• increased ~2.2-fold
• increased by ~3.5 %
• increased ~5-fold
• decreased by ~7 %
• decreased by ~3.5 %
• decreased ~2.2-fold

Problem 7: On a cold winter day (-23°C), a balloon filled with air at room temperature (27°C), is taken outside. The atmospheric pressure inside the room and outside in the cold is the same. After two hours, the volume of this balloon will be
Answers:

• half of the original volume
• 20% bigger than the original volume
• twice the original volume
• ~83% of its original volume
• the same as the original volume

Problem 8: Estimate the volume of 0.5 moles of nitrous oxide at 0°C. (MM is 44g/mol ) at the atmospheric pressure (1atm)
Answers:

• ~23L
• 11.2L
• insufficient information
• 44 cm³

Problem 9: At 0 °C and 1 atm, how many moles of H₂ are contained in a 1.0 L container?
Answers:

• 6.22 mol
• 0.004 mol
• 22.4 mol
• 0.045 mol
• 2 mol

Problem 10: The following SI units need to be used in the gas law formula ( R is expressed in JK^-1 mol^-1 ) :
Answers:

• P must be expressed in N/m² , V in cubic meters
• temperature ( T ) must be expressed in degress Kelvin and volume in square meters
• P must be expressed in bars , V in cubic meters
• temperature ( T ) must be expressed in degress Celsius and pressure in pascals
• P must be expressed in pascals , V in liters