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When the temperature is 18°C, a gas has a volume of 43.0 L and a pressure of 765. torr. If the volume changes to 26.0 L and the temperature changes to 86°C, what is the pressure if the amount of gas stays the same? Answer in torr using three significant figures.
A vessel contains CO, H2, and O2. The mole fractions of H2 and O2 are 0.17 and 0.62, respectively. What would be the mole fraction of CO?
A fluorescent tube light with a length of 4.00 ft and a diameter of 1.5 inches contains mercury vapor and argon. A specific fluorescent bulb contains 0.263% mercury and has total pressure inside the lamp is 304 Pa. How many argon atoms are present in the lamp? State all assumptions made.
Calculate the molar mass of the unknown liquid using the given information obtained via the Dumas method:
mass of vapor = 1.3214 g
volume of flask = 500 mL
pressure = 754.3 Torr
temperature = 99.43 ºC
A sample of phosgene gas (COCl2) is kept at 850 torr and 35.0 °C. Determine its density.
A 135 mL sample of butane gas is collected over water at a temperature of 28 °C and pressure of 742 torr. Calculate the number of moles of butane in the collected sample.
What would be the density of oxygen, O2, at each condition?
a) STP
b) 1.56 atm and 66.0°C
Answer in grams per liter.
Consider the following experiment:
A Kr gas was allowed effuse through a small hole under constant pressure. The 2 L sample of Kr took 96.0 s to effuse. Another gas of unknown identity went through the same conditions. It took a 2 L sample of the unknown gas 55.5 s to effuse. Calculate the molar mass of the unknown gas.
Explain how the following changes affect the vrms of a gas:
(a) increasing pressure
(b) decreasing volume
(c) decreasing temperature
At STP, consider the three separate 1.0-L samples of He, O2, and Cl2 behaving ideally. Rank them in order of increasing average kinetic energy and increasing average velocity.
Which of the following statements is true for the image below if gases A and B are different gases?
Identify which molecule has the higher molar mass and which has the higher rate of effusion based on the molecular velocity distribution shown below.
Legend:
Molecule X → blue
Molecule Y → yellow
Two containers with a volume of 150 L are filled with gas at 350 K. One container holds 5 moles of Ar, while another holds 5 moles of CO. Based on kinetic molecular theory, which gas has a faster average speed?
Determine the pressure exerted by a 1.50 mol sample of NH3 gas at 60.0°C that occupies a volume of 56.8 L considering that (a) it behaves as an ideal gas (b) it behaves as a real gas (using the van der Waals equation; a = 4.17 L2•atm/mol2; b = 0.0371 L/mol)
On average, a television consumes 107 kWh of electricity per year. Calculate the kilojoules of electricity consumed in three years.
Determine the potential energy of a 48 kg swimmer at the apex of his dive from an 8.0 m platform if the apex of the dive is 8.6 m relative to the surface of the water
Which of the following statement is true based on the first law of thermodynamics?
The internal energy (∆E) and the enthalpy change (∆H) are the same for a reaction and both are measured at constant pressure. Is this statement true or false?
Why do the surroundings feel colder during an endothermic reaction?
Suppose that 0.130 kg of a substance is initially at 25.0 °C. What is the final temperature of the substance upon absorbing 2.35 kJ of heat if its specific heat capacity is 0.456 J/g°C?
An empty 3.50-L steel container was filled with a mixture consisting of 1.20 atm of C3H8 and 7.20 atm of O2 at 350 °C. According to the equation C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g) ΔH° = –2220 kJ, the C3H8 was combusted using a spark. Given that the mass of the steel container is 15.700 kg, the average molar heat capacity of the mixture is 14.5 J/(mol·°C) and the heat capacity of steel is 0.449 J/(g·°C), determine the final temperature inside the container after the combustion.
A bomb calorimeter with a heat capacity of 6.35 kJ/°C was initially at 24.1 °C. The temperature rises to 29.9 °C when 3.236 g of octane (C8H18) is burned.
Calculate the enthalpy of combustion of octane (C8H18).
Calculate the final temperature of the mixture of 75.0 mL each of butanol at 5.0 °C and water at 30.1 °C assuming no heat is lost to the surroundings.
The density of butanol and water is 0.81 g/mL and 1.0 g/mL respectively.
A certain fuel mixture is made up of the following gases in percent by volume: 30.6% propane (C3H8), 52.3% butane (C4H10), and the rest pentane (C5H12). The mixture is stored at 298 K and 745 mmHg in a 2.50 L gas tank. When the fuel mixture is subjected to complete combustion, calculate the total heat that is emitted. Note that water vapor is produced in the combustion reaction.
ΔH°f (kJ/mol)
C3H8(g) –103.85
C4H10(g) –125.7
C5H12(g) –146.9
O2(g) 0
CO2(g) –393.5
H2O(g) –241.8
Provide the balanced formation equation for Na2SiO3(s) using elements in their standard states.
Ferric oxide (Fe2O3) and hydrogen gas (H2) are created when ferrous oxide (FeO) and water react.
2 FeO(s) + H2O(l) → Fe2O3(s) + H2(g) ΔH°rxn = 5.60 kJ
Using the following information, calculate H°f for FeO.
Fe2O3(s): ΔH°f = −824.2 kJ/mol
H2(g): ΔH°f = 0
H2O(l): ΔH°f = −285.8 kJ/mol
Consider the dissolution of CaCl2. Determine ΔH for the reverse reaction.
CaCl2(s) → Ca2+(aq) + 2 Cl–(aq) ΔH = –81.5 kJ/mol