Physical Chemistry and ChE Thermodynamics – Exam

How many Chlorine atoms are there in the refrigerant R-151?

An unknown compound weighing 8.05 grams was dissolved in 0.1 kg of benzene. This caused the vapor pressure of the latter to decrease to 94.8 torr from 100.0 torr. What is the molar mass of the solute?

Which of the following is a commonly used term referring to the Leclanche cell?

How much PbSO₄ will be decomposed if a 5A current will be passed through a lead storage cell during charging process that lasts for 1 hour?

Given △G₂₉₈/kJ-mol^-1 = 0 for Zn(s) and Cu(s), -147.06 for Zn²⁺(aq) and 65.49 for Cu²⁺(aq), calculate the cell potential at the given condition.

What can be concluded about the previously described cell

A simple cubic structure follows which formula for the volume of its unit cell? Note r = radius of the atom.

Calculate the change in the molar Gibbs free energy of hydrogen gas when it is compressed isothermally from 1 atm to 100 atm at 298K.

Consider the reaction: NO_2(g)  ↔ N2O_4(g). If the equilibrium constant K_p for the said reaction is about 0.480 at room temperature, determine the value of K_c at the same temperature.

What is the percentage of the lighter alcohol in the vapor above a solution that is composed of equal weights of methanol and ethanol. Assume that the solution is ideal at 60C.

Refer to the equilibrium reaction given below:

SO_2(g) + O_2(g) ↔ SO_3(g)              △H = -45kcal

The concentration of SO₃ at equilibrium will increase if

Refer to the equilibrium reaction given below:

SO_2(g) + O_2(g) ↔ SO_3(g)              △H = -45kcal

The number of moles of oxygen at equilibrium will decrease if

Which of the following is not an allotrope of carbon?

After releasing 2000 milligrams of N₂, the remaining contents inside the tank now exerts a pressure of 480 mmHg at 30°C from initial conditions of 82°C and 940 mmHg. How many milligrams of gas were left in the same tank?

Consider a sample of 3 moles of an ideal diatomic gas at 200K is compressed reversibly and adiabatically until its temperature reaches 250K. Given that C_v=27.5 J/mol-K,

Calculate the work associated with the process.

Consider a sample of 3 moles of an ideal diatomic gas at 200K is compressed reversibly and adiabatically until its temperature reaches 250K. Given that C_v=27.5 J/mol-K,

Calculate the change in the enthalpy of the system.

The times that a steel ball (7.80×10³ kg/m³) required to drop through water and a commercial shampoo were 4.50 secs and 7.00 secs respectively. Given that the density of the latter is 1.03×10³ kg/m³, how much more viscous is the shampoo?

If a hydrogen gas is at 0C, calculate the most probable molecular velocity of the said gas in m/s assuming that hydrogen behaves ideally?

Determine the heat of reaction for C₆H₆ + H₂  → C₆H₁₂ if the enthalpies of combustion at 25C are -3273, -286.1 and -3924 kJ/mol for benzene, hydrogen and cyclohexane respectively.

What is the COP of a refrigerator when operated as a heat pump if it is 400-kW rated engine that can absorb heat of about 1600 kW?

According to the Second Law of Thermodynamics, calculate the the maximum power output from an engine that operates with T_H = 1540F and T_C = 40F while employing 10⁶ BTU/hr of fuel.

It is defined as the temperature at which real gases exhibit ideal gas behavior for an appreciably longer range of pressure compared to its other temperatures?

What is the numerical value of the gas constant when expressed in L-torr/K-mol?

The turbine in a hydroelectric plant is fed by water falling from a height of 30m. Assuming 95% efficiency in converting potential energy to electrical energy and 10% loss of resulting power during transmission, how many metric tons of water per hour are needed to keep a 100W light bulb burning?

Given the reaction below, calculate the difference between its change in Gibbs and Helmholtz free energies at 25C and 1 atm.

H_2(g) + ½ O_2(g) ↔ H₂O_(l)

What is the degree of freedom of a system that is composed of moist air and water inside a closed container?

At water’s triple point, steam, ice and liquid water are in equilibrium pressure of 4.58 mmHg. At this same temperature, the heats of fusion and vaporization of water is 1436 cal/mole and 10,767 cal/mole respectively. What is the corresponding entropy of sublimation per mole of water?

Which of the following cycle does not typically use air as its working fluid?

A Brayton cycle compresses air to a pressure of 88.2 psia. Three moles of air are entering at 25C with a C_p of (7/2)R. If the cycle receives heat at 560 BTU/mol of air, what is the maximum amount of work it produces?

Calculate the quality of the supplied steam if a supply line carries a two-phase mixture of steam at 300 psi and a small fraction of the flow in the line is diverted through a throttling calorimeter and exhausted to the atmosphere at ambient pressure and a temperature of 250°

It is a type of process that does not involve any amount of energy transfer by heat.

Air will be compressed with the use of a compressor that has a shaft work of 240 KJ/kg and will be further released using a nozzle. The initial velocity is zero with 1 bar as its initial pressure under 250C temperature.  The pressure at the end of the compressor has been measured to be 3 bars.  The velocity and pressure after the nozzle is said to be 600 m/s and 1 bar respectively.  The entire system works in an isothermal condition.

Calculate for the change in the kinetic energy involved in the process.

Air will be compressed with the use of a compressor that has a shaft work of 240 KJ/kg and will be further released using a nozzle. The initial velocity is zero with 1 bar as its initial pressure under 250C temperature.  The pressure at the end of the compressor has been measured to be 3 bars.  The velocity and pressure after the nozzle is said to be 600 m/s and 1 bar respectively.  The entire system works in an isothermal condition.

Calculate for the heat involved for the same process in the previous problem.     

Eight grams of oxygen gas at 27C and 10 atm expands adiabatically and reversibly to a final pressure of 1 atm. The work done in the process expressed in Joules is

If 6 liters of a gas at a pressure of 100 kPa are compressed reversibly according to PV²=k until the volume is a third of its original amount, how much work was used for the compression?

Fifty five gallons of water passes through a heat exchanger and absorbs 28,000 BTU of heat. The exit temperature is 570 R.  What is the inlet water temperature in F?

Consider that C₁₀H₈ melts at 80.2°C. The vapor pressure of its liquid form is 10 torr at 85.8°C and 40 torr at 119.3°C.

What is its normal boiling point?              

Consider that C₁₀H₈ melts at 80.2°C. The vapor pressure of its liquid form is 10 torr at 85.8°C and 40 torr at 119.3°C.

Calculate its entropy of vaporization at the boiling point.

The fugacity coefficient of a certain gas at 200 K and 50 bar is 0.72. Calculate the difference of its chemical potential from that of a perfect gas in the same state.