Chapter 5 AP Chem Finals Review
At 127 C, the pressure in vessel is found to be higher than that in vessel 2. Which of the following reactions best accounts for the observation?
2NaHCO3(s) Na2CO3(s) + CO2(g) +H2O(g)
Under which of the following conditioned of temperature and pressure with H2 gas be expected to behave most like an ideal gas?
600K and .10 atm
On the basis of the data provided above, the gas in container 3 could be?
C2H6
Under the conditions given, consider 1,2, and 4 only. The average speed of the gas particles is
Greatest in 4
The best explanation for the lower pressure in container 4 is that SO2 molecules
Have a stronger intermolecular attraction than the other gases
A 0.5 mole sample of He(g) and a .5 mole sample of Ne(g) are places separately in two 10.0 L rigid containers at 25 C. each container has a pinhole opening. Which of the gases, He or Ne will escape faster through the pinhole and why?
He will escape faster because the He atoms are moving faster at a higher average speed than Ne atoms.
The volume of a sample of air in a cylinder with movable piston is 2.0L at a pressure P1, as shown in the diagram above. The volume is increases to 5.0 L as the temperature is held constant. The pressure of the air in the cylinder is now P2. What effect do the volume and pressure changes have on the average kinetic energy of the molecules in the sample?
The average kinetic energy stays the same.
At 127 C, the entire sample of I2 is observed to have vaporized. How does the mass of vessel 5 at 27 C compare to its mass at 127 C?
The mass is the same, since the number of each type of atom in the vessel is constant.
The reaction between NO(g) and O2(g) to produce NO2(g) in a rigid reaction vessel is represented in the diagram above. The pressure inside the container is recorded using a pressure gauge. Which of the following statements correctly predicts the change in pressure as the reaction goes to completion at constant temperature, and provided the correct explanation?
The pressure will decrease because there are fewer molecules of product than of reactants.
Free Response A chemist puts 45.0 g of nitrogen gas and 53.4 g of oxygen gas into a ridged sealed 56.0L container. a) Calculate the total pressure in the container at 110 C. b) Calculate the mole fraction of oxygen gas in the container c) The chemist ignites the mixture in the container and a reaction occurs according to the equation below. Find the partial pressure of nitrogen dioxide in the container at 110 C.
a) 18.42 ATM b) .509 c) 2N2(g) + O2(g) 2N2O(g)
Free Response : A student is given the task of determining the identity of an unknown gas, and collects the following data in the table below. a) Calculate molar mass of unknown gas: MM*P=D*R*T b) The unknown gas was pentane (C5h12). Calculate the percent error for this experiment
a) 58.0 g/mol b) 19.6%
Free Response 1) Represented above are five identical balloons, each filled to the same volume at 25 C and 1.0 atm pressure with the pure gas indicated. a) Which balloon contains the greatest mass of gas? Explain b) Compare the average kinetic energies of the gas molecules in the balloons. c) Which balloon contains the gas that would be expected to deviate most from the behavior of an ideal gas? d)12 hours after being filled, the balloons have decreases in size. Predict which balloon will be the smallest. Explain your reasoning.
a) The balloon with CO2 contains greatest mass, molar mass is 44.01 b) The average kinetic energies of the gas molecules in the balloons is the same since the temperature for every balloon is the same. c) The balloon containing Co2 deviates from ideal behavior since it is the one with the largest mass and most electrons and strongest IMF's. d) He because it is the smallest so it will release the fastest