Physics
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Real gases can approach the behavior of ideal gases under certain conditions. Helium is thought to be the closest to an ideal gas with γ = 1.660. Calculate the molar heat capacities i) CV and ii) Cp of helium.
A heat engine contains two moles of an ideal gas confined in a cylinder with a moveable piston. Fuel combustion provides 873 J of heat that increases the gas temperature from 45 °C to 60 °C under constant pressure. The heated gas expands and does 249 J of work on the piston. Calculate the ratio of heat capacities (γ) for the gas.
A student heats a vessel enclosing argon gas. During this process, argon absorbs an amount Q0 of heat energy and expands at constant pressure. Find the percentage of heat energy involved in the expansion work of argon.
A car radiator is filled with pure water. The radiator cap keeps the pressure at 3.5 atm and pushes the boiling point of water to 140°C. At 3.5 atm, the heat of vaporization is 2.11 × 106 J/kg. What would be the increase in the internal energy (ΔU) of water if 250 g of the steam were formed from water at this temperature and pressure? At 3.5 atm and 140 °C, the densities of water and steam are 928.5 kg/m3 and 1.93 kg/m3, respectively.
A chef wants to reduce the cooking time by a few minutes. To succeed, he raises the pressure to 4 atm inside the cooker. At this pressure, the boiling point of water, the density of water, and the density of steam are 144 °C, 922.2 kg/m3, and 2.163 kg/m3 respectively. What is the work (W) done by 200 g of steam formed at 144 °C inside the cooker?
A sample of gas has its volume reduced isobarically from 3 L to 1 L inside a vertical cylinder with a movable piston at a pressure of 1.25 atm. The gas temperature decreases by 10 °C and its internal energy by 1000 J. What is the heat exchanged (Q) during the process if (i) the gas is ideal, or (ii) the gas is not ideal?
At a temperature of 30 °C, a rubber balloon is filled with 3 moles of helium. The balloon is left out in the sun to expand. Helium absorbs 1000 J of heat and does 800 J of work on the rubber. Determine the final temperature (Tf) of helium.
During a laboratory experiment, a student uses a piston-cylinder assembly initially containing 10 cm3 of an ideal gas. The cylinder is heated with an electric resistor to maintain constant pressure of the expanding gas. The net energy added to the gas by heat is 5 J and the pressure sensor inside the cylinder indicates a value of 3 × 105 Pa. Find the work done by the gas if the volume of the cylinder is doubled.
A silicate container containing 289 g of air is sealed with a piston. The gas inside the container expands under isobaric conditions and produces 500 J of work. What would be the final temperature (Tf) of the gas if the initial temperature is 290 K? The molar mass of air is 28.9 g/mol.
Equal samples (0.25 mol) of an ideal diatomic gas are treated through the processes represented below. Determine the amount of heat required in each process.
Interpret the information contained in the equation below that was used to solve a certain problem:
50 J = −(0.0142 mol)(8.31 J/mol K)(T)Ln(1/5).
Turbo boost allows heat engines to take in air at pressures above atmospheric pressure. A 0.300 L cylinder takes in air at 1.60 atm and 25 °C and 650 J of work is done compressing the air adiabatically. Find the final temperature and volume of the air in the cylinder.
A neon sample undergoes adiabatic expansion from V0 to 2V0, where V0 is the initial volume. Will the mean free path increase/decrease, and by what factor? If not, give a reason.
At an initial pressure of 4.0 atm and a temperature of 200°C, 0.15 mol of N2 gas is present in a closed vessel. Following an adiabatic expansion process, the volume of the gas triples. Determine the final pressure of the nitrogen gas within the vessel.
An adventurer brings an insulated, airtight cylinder containing 0.15 mol of argon gas (Ar) to assist in inflating a portable shelter. The initial temperature and pressure of the gas are 120°C and 2.5 atm, respectively. As the climber inflates the shelter, the gas expands adiabatically until the pressure drops by forty percent. Determine the argon gas's final temperature.
On a high-altitude weather balloon, a strong, insulated container holds a sample of gas. "As the balloon descends to a lower altitude, the external pressure changes, causing the volume of the gas to decrease to one-third of its initial value, and the pressure to increase by a factor of 3. In this case, determine the specific heat ratio of the gas in the container.
0.20 grams of neon is treated through the thermodynamics paths shown below. Calculate the net heat energy that flows into/out of the gas in the three-step process.
2.5 g of H2 gas at room temperature and pressure undergoes adiabatic compression to 15 atm. Express the final volume in terms of the initial volume, Vf = _?_ Vi.
The volume of a sample of helium changes adiabatically from V0 to 1.5V0, where V0 is the initial volume. Determine if the thermal energy of the helium sample increases/decreases and by what factor. If there is no change, state why.
Neon gas expands adiabatically from V0 to 3V0, where V0 is the initial volume. Find the factor by which Cv (molar specific heat at constant volume) is increased/decreased. If not changed, state why.
You are provided with two gas samples; a polyatomic (Cp/Cv = 4/3) and a monoatomic gas (Cp/Cv = 5/3). You are asked to mix the two gases to yield a gas with Cp/Cv = 7/5. Calculate the percentage of polyatomic molecules in the mixture.
A container left in the sun contains 1.80 moles of an ideal gas at 68.0°C and 2.00 atm pressure. Calculate the work required to compress the gas to 1/4 of the initial volume while the pressure remains constant at 2.00 atm.
A water pump impeller can be considered to stir the water in an isolated system. Calculate heat absorbed by 2.0L of water when its temperature rises from 18°C to 60°C if no net flow of water occurs.