Chapter 6 Part 1
A high-performance bicycle tire has a pressure of 132 psi. What is the pressure in mmHg?
6.82 x 10^(3) mmHg
A sample of methane, CH4, occupies 260 mL at 32oC under a pressure of 0.500 atm. At what temperature would it occupy 500 mL under a pressure of 1200 torr?
1852.2 K
A mixture of helium, neon, and argon has a total pressure of 558 mmHg. If the partial pressure of helium is 341 mmHg and the partial pressure of neon is 112 mmHg, what is the partial pressure of Argon?.
ππ΄π = 105 πππ»π
How many dietary (nutritional) calories are equivalent to 1.75 x 10^(3) kJ
418 πΆππ
An LP gas tank in a home barbeque contains 13.2 kg of propane, C3H8. Calculate the heat (in kJ) associated with the complete combustion of all propane in the tank. (LP= liquefied petroleum).
C3H8(π) + 5O2(g) β 3CO2 π + 4H2O(π)
βπ»ππ₯π = β2044 kJ
β6.12x10^(5) kJ
A lab-barometer indicates that the atmospheric
pressure is 764.7 torr. A sample of gas is placed in
a flask attached to an open-end mercury
manometer, and a meter stick is used to measure
the height of the mercury in the two arms of the
U tube. The height of the mercury in the open-
end arm is 136.4 mm, and the height in the arm
in contact with the gas in the flask is 103.8 mm.
What is the pressure of the gas in the flask in
atmospheres?
1.049 atm
What volume would 50.0 g of ethane, C2H6, occupy at 140 oC under a pressure of 1.82 x 10^(3) torr?
23.6 L
How many liters of oxygen (at STP) are required to form 10.5 g of H2O?
2 H2(g) + O2(g) β 2 H2O(g)
6.53 πΏ π2
Reacting 50 mL of H2(g) with 50 mL of C2H4(g) produces 50 mL of C2H6(g) at 1.5 atm. If the reaction produces 3.1 x 102 J of heat and the decrease in volume requires the surroundings do 7.6 J of work
on the gases, what is the change in internal energy of the gases?
E = (-310 J) + (+7.6 J) = -302.4 J = -3.0 x 102 J
Magnesium metal reacts with hydrochloric acid according to the balanced equation:
Mg π + 2HCl ππ β MgCl2 ππ + H2(π)
In an experiment to determine the enthalpy change for this reaction, 0.158g Mg metal is combined with enough HCl to make 100.0 mL of solution in a coffee-cup calorimeter. The HCl is sufficiently concentrated so that the Mg completely reacts. The temperature of the solution rises from 25.6 oC to 32.8 oC as a result of the reaction. Find οHrxn for the reaction as written.
Use 1.00 g/mL as the density of the solution and Cs, sol = 4.18 J/g oC as the specific heat capacity of the solution.
βπ»ππ₯π = β4.6 x105 J
At 25oC a sample of He has a volume of 4.00 x 10^(2) mL under a pressure of 7.60 x 10^(2) torr. What volume would it occupy under a pressure of 2.00 atm at the same T?
V2 = 2.00 x 10^(2) mL
A flying balloon contains 1.2 x 10^(7) L of He at a pressure of 737 mm Hg and 25 Β°C. What mass of He does the balloon contain? Mw He = 4.00g/mol
1.9 π₯ 10^(6) π
What is the root mean square velocity of He atoms at room temperature (25.0oC)
1363 π/π
How much heat is absorbed by a copper penny with mass 3.10 g whose temperature rises from β8.0 Β°C to 37.0 Β°C?
53.7 π½
Calculate the βπ»rxn^(o) of:
CH4 π + 2O2 π β CO2 π + 2H2O(π)
βπ»rxn^(o) =
Hf => CH4 = -74.6, O2 = 0, CO2 = -393.5, H2O = -241.8
Use appendix IIB for the values of Hf
βπ»rxn^(o) = β802.5 ππ½
A sample of hydrogen, H2, occupies 1.00 x 10^(2) mL at 25.0 oC and 1.00 atm. What volume would it occupy at 50.0 oC under the same pressure?
V2 = 1.08 x 10^(2) mL
The density of a gas is 0.391 g/L at 70.5 torr and 22.3 Β°C. Calculate its molar mass (Mw).
102. π/πππ
A sample of hydrogen, H2, was found to effuse through a pinhole 5.2 times as rapidly as the same volume of unknown gas (at the same temperature and pressure). What is the molecular weight of the unknown gas?.
54 π/πππ
A certain process results in a gas system releasing 68.3 kJ of energy. During the process, 15.8 kcal of heat is released by the system. If the external pressure is kept constant at 1.00 atm and the initial
volume of the gas is 10.0 L, what is the final volume of the gas?
(1 cal = 4.184 J, 101.3 J = 1.00 atm L)
V2 = 32.3 L
Use the standard enthalpies of formation to determine βπ»ππ₯π^(π) for the reaction:
4 NH3 π + 5 O2 π β 4 NO π + 6 H2O(π)
Hf => NH3 = -45.9 , O2 = 0, NO = 91.3, H2O = -241.8
Hf can be found on appendix IIB
βπ»rxn^(o) = β902.0 ππ½
A 0.225 mol sample of He has a volume of 4.65 L. How many moles must be added to give 6.48 L?
moles added = 0.313548 mol - 0.225 mol = 0.0885 mol
A sample of gas has a mass of 0.136 g. Its volume is 0.112 L at a temperature of 298 K and a pressure of 1.06 atm. Calculate the molar of the gas.
28.0 π/πππ
Calculate the pressure exerted by 84.0 g of ammonia, NH3, in a 5.00 L container at 200. oC using Van der Waals equation. π = 4.17 πΏ2 ππ‘π/ πππ^(2)
π = 0.0371 πΏ / πππ
P = 35.7 atm
A 32.5 g cube of aluminum initially at 45.8 Β°C is submerged into 105.3 g of water at 15.4 Β°C. What is the final temperature of both substances at thermal equilibrium?
πΆπ ,π΄π = 0.903 Ξ€J g oC
πΆπ ,π»2π = 4.18 Ξ€J g oC
ππππππ = 17.3 ππΆ
A city of 100,000 people uses approximately 1.0 x 1011 kJ of energy per day. Suppose all of that energy comes from the combustion of liquid octane (C8H18) to form gaseous water and gaseous carbon
dioxide. Use standard enthalpies of formation to calculate βπ»ππ₯π^(π) for the combustion of octane and then determine the number of kilogram of octane necessary to provide this amounts of energy.
C8H18 π + O2(g) -> + H2O π + CO2(π)
π»π => C8H18 = -250.1, O2 = 0, H2O = -241.8, CO2 = -393.5 kJ
2.3 x 10^(6) kg C8H18