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physical chemistry
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Physical Chemistry
In the production of many microelectronic devices, continuous chemical vapor deposition (CVD) processes are used to deposit thin and exceptionally uniform silicon dioxide films on silicon wafers. One
Trichloroethylene, a widely used degreasing solvent for machine parts, is produced in a two-step reaction sequence. Ethylene is first chlorinated to yield tetrachloroethane, which is
The standard heat of the reactionΔHr = 69:36 kJ.(a) Is the reaction exothermic or endothermic at 25°C? Would you have to heat or cool the reactor to keep the temperature constant? What would the
The standard heat of the combustion reaction of liquid n-hexane to form CO2(g) and H2O(l), with all reactants and products at 77°F and 1 atm, is ΔHr = 1:791 × 106 Btu. The heat of vaporization of
The standard heat of combustion of liquid n-octane to form CO2 and liquid water at 25°C and 1 atm is ΔĤc = 5471 kJ/mol.(a) Briefly explain what that means. Your explanation may take the form
The standard heat of the reactionis ΔHr = 904:7 kJ.(a) Briefly explain what that means. Your explanation may take the form “When ______ (specify quantities of reactant species and their physical
Taking as references pure liquid sulfuric acid at 77°F and pure liquid water at 32°F and without using Figure 8.5-1, calculate Ĥ(Btu/lbm) for each of the following substances. For each substance,
Aqueous sulfuric acid solutions containing 15.0 wt% H2SO4 and 80.0 wt% H2SO4 are mixed to form a 30.0 wt% product solution. The 15% solution was in a laboratory in which the temperature was 77°F.
A stirred tank with volume Vt(L) is charged with Vl(L) of a liquid, B. The space above the liquid (volume Vg = Vt - Vl) is filled with a pure gas, A, at an initial pressure P0(atm). The initial
Fifty milliliters of 100% H2SO4 at 25°C and 84.2mL of liquid water at 15°C are mixed. The heat capacity of the product solution is 2.43 J/(g °C).(a) Estimate the maximum temperature attainable by
Two hundred kilograms per hour of an aqueous solution containing 20.0 mole% sodium acetate (NaC2H3O2) enters an evaporative crystallizer at 60°C. When the solution is exposed to the low pressure in
An 8-molar hydrochloric acid solution [SG = 1:12, Cp = 2:76 J/(g °C)] is produced by absorbing hydrogen chloride [HCl(g)] in water. Liquid water enters the absorber at 25°C and gaseous HCl is fed
Sodium hydroxide is dissolved in enough water to make up a 20.0 mole% solution.(a) If the NaOH and water are initially at 77°F (25°C), how much heat (Btu/lb product solution) must be removed for
The heat of solution of ammonia in water at 1 atm is(a) Calculate the enthalpy change that accompanies the dissolution of 200 mol of NH3 in 400 mol of water at 25°C and 1 atm.(b) If you actually
Spray cooling is a technique for cooling and either humidifying or dehumidifying air by contacting it with a spray of liquid water.
Spray cooling is a technique for cooling and either humidifying or dehumidifying air by contacting it with a spray of liquid water.
Spray cooling is a technique for cooling and either humidifying or dehumidifying air by contacting it with a spray of liquid water.
Spray cooling is a technique for cooling and either humidifying or dehumidifying air by contacting it with a spray of liquid water.
Asolution of sugar in water is to be concentrated from 5 wt%sugar to 20%sugar. The solution is at about 45°C when it is fed continuously to a bubble column. Air at 45°C with a dew point of 4°C is
Air at 45°C (dry bulb) and 10% relative humidity is to be humidified adiabatically to 70% relative humidity.(a) Use the psychrometric chart to estimate the adiabatic saturation temperature of the
Wet wood chips are dried in a continous rotary dryer that operates at atmospheric pressure. The chips enter at 19°C with a water content of 40 wt% and must leave with a moisture content of less than
Workers in the petrochemical industry often wear flame-retardant jumpsuits. Unfortunately, the material from which they are made hinders evaporation of perspiration, and consequently heat stress can
Humid air is enclosed in a 2.00-liter flask at 40°C. The flask is slowly cooled. When the temperature reaches 20°C, drops of moisture become visible on the flask wall. Although the pressure in the
An open vessel containing 0.205 lbm of liquid water is placed in an empty room 5 ft wide, 4 ft deep, and 7 ft high, which initially contains dry air at 90°F. All the water evaporates without
An outside-air sample is taken on a day when the temperature is 78°F and the relative humidity is 40%.(a) Use the psychrometric chart to state as many physical properties of the air as you can
Freeze concentration is used to produce a fruit-juice concentrate. A stream of fresh juice containing 12 wt% soluble solids in water at 20°C is combined with a recycle stream to form a
The manufacturers of a new oatmeal product want to determine the least expensive way to safeguard and transport their product. They choose lyophilization (freeze drying), which removes most of the
Freeze drying is a technique for dehydrating substances at low temperatures, thereby avoiding the degradation that may accompany heating. The material to be dried is cooled to a temperature at which
A small pharmaceutical firm plans to manufacture a new drug and has hired you as a consultant to design a condenser to remove the drug from a gas–vapor mixture. The mixture, which contains 20 mole%
A small pharmaceutical firm plans to manufacture a new drug and has hired you as a consultant to design a condenser to remove the drug from a gas–vapor mixture. The mixture, which contains 20 mole%
A small pharmaceutical firm plans to manufacture a new drug and has hired you as a consultant to design a condenser to remove the drug from a gas–vapor mixture. The mixture, which contains 20 mole%
A small pharmaceutical firm plans to manufacture a new drug and has hired you as a consultant to design a condenser to remove the drug from a gas–vapor mixture. The mixture, which contains 20 mole%
Fish and wildlife managers have determined that a sudden temperature increase greater than 5°C would be harmful to the marine ecosystem of a river. Warmer waters contain less dissolved oxygen and
The off-gas from a reactor in a process plant in the heart of Freedonia has been condensing and plugging up the vent line, causing a dangerous pressure buildup in the reactor. Plans have been made to
An equimolar liquid mixture of n-pentane and n-hexane at 80°C and 5.00 atm is fed into a flash evaporator at a rate of 100.0 mol/s. When the feed is exposed to the reduced pressure in the
A mixture of n-hexane vapor and air leaves a solvent recovery unit and flows through a 70-cm diameter duct at a velocity of 3.00 m/s. At a sampling point in the duct the temperature is 40°C, the
A gas stream containing n-hexane in nitrogen with a relative saturation of 90% is fed to a condenser at 75°C and 3.0 atm absolute. The product gas emerges at 0°C and 3.0 atm at a rate of 746.7
Estimate the heat of vaporization (kJ/mol) of benzene at 25°C, using each of the following correlations and data: (a) The heat of vaporization at the normal boiling point and Watson’s
In gas adsorption a vapor is transferred from a gas mixture to the surface of a solid. (See Section 6.7.) An approximate but useful way of analyzing adsorption is to treat it simply as condensation
Polyvinylpyrrolidone (PVP) is a polymer product used as a binding agent in pharmaceutical applications as well as in personal-care items such as hairspray. In the manufacture of PVP, a spray-drying
As part of a design calculation, you must evaluate an enthalpy change for an obscure organic vapor that is to be cooled from 1800°C to 150°C in a heat exchanger. You search through all the standard
Sixty-five liters of liquid ethanol at 70.0°C and 55 L of liquid water at 20.0°C are to be mixed in a wellinsulated flask. The energy balance for this constant pressure process is Q = ΔH. (a)
Pure ethane is burned completely with preheated 20% excess air. The combustion product gas passes through an insulated heat exchanger (the preheater) in which it transfers heat to the air that will
Saturated steam at 300°C is used to heat a counter currently flowing stream of methanol vapor from 65°C to 260°C in an adiabatic heat exchanger. The flow rate of the methanol is 6500 standard
Ever wonder why espresso costs much more per cup than regular drip coffee? Part of the reason is the expensive equipment needed to brew a proper espresso. A high-powered burr grinder first shears the
The flow of groundwater often plagues construction of tunnels and other underground systems. One way of preventing it is with an ice seal—freezing the water in the soil so that the ice formed is a
Propane is to be burned with 25.0% excess air. Before entering the furnace, the air is preheated from 32°F to 575°F. (a) At what rate (Btu/h) must heat be transferred to the air if the feed
Among the best-known building blocks in nanotechnology applications are nanoparticles of noble metals. For example, colloidal suspensions of silver or gold nanoparticles (10–200 nm) exhibit vivid
A stream of carbon monoxide flowing at 300 kg/min is cooled from 450°C to 50°C at a low pressure. (a) Calculate the required rate of cooling (kW), using the enthalpy function of APEx. Check
Use the enthalpy function of APEx to calculate ΔĤ for each of the processes given below and check your solution to Part (a) by using the heat capacity tabulated in Table B.2. (Include units in
Your next-door neighbor, Josephine Rackstraw, surprised her husband last January by having a hot tub installed in their back yard while he was away on an ice-fishing trip. It surprised him, all
The heat required to raise the temperature of m (kg) of a liquid from T1 to T2 at constant pressure is In high school and in first-year college physics courses, the formula is usually given
Calculate ΔĤ for each of the following processes. In each case, restate your result as a specific enthalpy relative to a reference state. [The solution—which you should verify—and the
Table B.7 of Appendix B gives the following values for steam at 400°C and 150 bar: (a) The value 2975 is not the true specific enthalpy of steam at the given condition. Why not? State the
Agricultural irrigation uses a significant amount of water, and in some regions it has overwhelmed other water needs. Suppose water is drawn from a reservoir and delivered into an irrigation ditch.
Water is to be pumped from a lake to a ranger station on the side of a mountain (see figure). The length of pipe immersed in the lake is negligible compared to the length from the lake surface to the
Water is to be pumped from a lake to a ranger station on the side of a mountain (see figure). The length of pipe immersed in the lake is negligible compared to the length from the lake surface to the
Ethanol is contained in a large tank under a pressure of 3.1 bar absolute. When a valve on the bottom of the tank is opened, the ethanol drains freely though a 1-cm ID tube whose outlet is 7.00 m
Your friend has asked you to help move a 60 inch ×78 inch mattress with a mass of 75 lbm. The two of you position it horizontally in an open flat-bed trailer that you hitch to your car. There is
A liquid mixture of benzene and toluene is to be separated in a continuous single-stage equilibrium flash tank. The pressure in the unit may be adjusted to any desired value, and the heat input
A rigid 6.00-liter vessel contains 4.00 L of liquid water in equilibrium with 2.00 L of water vapor at 25°C. Heat is transferred to the water by means of an immersed electrical coil. The volume of
A 200.0-liter water tank can withstand pressures up to 20.0 bar absolute before rupturing. At a particular time the tank contains 165.0 kg of liquid water, the fill and exit valves are closed, and
A mixture containing 65.0 mole% acetone (Ac) and the balance acetic acid (AA) is separated in a continuous distillation column at 1 atm. A flowchart for the operation is as follows: The stream
Three hundred L/h of a 20 mole% C3H8–80% n-C4H10 gas mixture at 0°C and 1.1 atm and 200 L/h of a 40 mole% C3H8–60% n-C4H10 mixture at 25°C and 1.1 atm are mixed and heated to 227°C at constant
The following diagram shows a simplified version of how a refrigerator works: In a liquid receiver 1 , a liquid refrigerant (any one of a number of halogenated hydrocarbons such as CCl2F2) is
Jets of high-speed steam are used in spray cleaning. Steam at 15.0 bar with 150°C of superheat is fed to a well-insulated valve at a rate of 1.00 kg/s. As the steam passes through the valve, its
Steam produced in a boiler is frequently “wet”—that is, it is a mist composed of saturated water vapor and entrained liquid droplets. The quality of a wet steam is defined as the fraction of
During a period of relative inactivity, the average rate of transport of enthalpy by the metabolic and digestive waste products leaving the body minus the rate of enthalpy transport by the raw
Liquid water is fed to a boiler at 24°C and 10 bar and is converted at constant pressure to saturated steam. (a) Use the steam tables to calculate ΔĤ(kJ/kg) for this process, and then
The specific enthalpy of liquid n-hexane at 1 atm varies linearly with temperature and equals 25.8 kJ/kg at 30°C and 129.8 kJ/kg at 50°C. (a) Determine the equation that relates Ĥ(kJ/kg) to
Define a system and simplify the open-system energy balance (Equation 7.4-15) for each of the following cases. State when possible whether nonzero heat and shaft work terms are positive or negative.
You are performing an experiment to measure the specific internal energy of a gas relative to a reference state of 25°C and 1 atm (at which conditions Û is arbitrarily set equal to 0). The gas is
Values of the specific internal energy of bromine at three conditions are listed here. (a) What reference state was used to generate the listed specific internal energies? (b) Calculate
Oxygen at 150 K and 41.64 atm has a tabulated specific volume of 4.684 cm3/g and a specific internal energy of 1706 J/mol. (a) The figure 1706 J/mol is not the true internal energy of one g-mole
A piston-fitted cylinder with a 6-cm inner diameter contains 1.40 g of nitrogen. The mass of the piston is 4.50 kg, and a 25.00-kg weight rests on the piston. The gas temperature is 30°C, and the
Methane enters a 3-cm ID pipe at 30°C and 10 bar with an average velocity of 5.00 m/s and emerges at a point 200 m lower than the inlet at 30°C and 9 bar. (a) Without doing any calculations,
Consider an automobile with a mass of 5500 lbm braking to a stop from a speed of 55 miles/h. (a) How much energy (Btu) is dissipated as heat by the friction of the braking process? (b)
A certain gasoline engine has an efficiency of 30%; that is, it converts into useful work 30% of the heat generated by burning a fuel. (a) If the engine consumes 0.80 L/h of a gasoline with a
The following equilibrium data have been obtained for the adsorption of nitrogen dioxide, NO2, on silica gel at 25°C and 1 atm: (a) Confirm that these data are reasonably correlated by the
Penicillin is produced by fermentation and recovered from the resulting aqueous broth by extraction with butyl acetate. The penicillin distribution coefficient K (mass fraction of penicillin in the
An aqueous waste stream leaving a process contains 10.0 wt% sulfuric acid and 1 kg nitric acid per kg sulfuric acid. The flow rate of sulfuric acid in the waste stream is 1000 kg/h. The acids are
Serine (Ser, molecular weight=105.1 g/mol) is a nonessential amino acid produced by fermentation. As with many other fermentation products, substantial downstream processing is required to meet
Various amino acids have utility as food additives and in medical applications. They are often synthesized by fermentation using a specific microorganism to convert a substrate (e.g., a sugar) into
Various amino acids have utility as food additives and in medical applications. They are often synthesized by fermentation using a specific microorganism to convert a substrate (e.g., a sugar) into
An aqueous solution containing 35 wt% MgSO4 is fed to an evaporative crystallizer operating at 50°F. The vapor generated is 20% by mass of the feed. The solution, which contains 23 wt% MgSO4, and
An aqueous solution of potassium hydroxide (KOH) is fed to an evaporative crystallizer at a rate of 875 kg/h. The crystallizer operates at 10°C and produces crystals of KOH•2H2O. Water evaporated
A liquid mixture containing 40.0 mole% methanol and 60.0 mole% 1-propanol is placed in an open vessel and heated slowly. Estimate the temperature at which the mixture begins to boil. List assumptions
A mixture of benzene and toluene is in a tank whose pressure is maintained at 2.0 atm. Observation through a sight glass on the vessel shows that half of the tank volume is occupied by liquid.
In this problem you will use a spreadsheet to create a Txy diagram for the benzene-chloroform system at 1 atm. Once the spreadsheet has been created, it can be used as a template for vapor–liquid
This problem deals with two-phase mixtures of benzene and toluene at equilibrium. The vapor phase may be assumed ideal and Raoult’s law can be used for all system compositions. Use APEx and Solver
A liquid mixture contains N components (N may be any number from 2 to 10) at pressure P mm Hg. The mole fraction of the ith component is xi(i = 1; 2; ... ;N), and the vapor pressure of that
A liquid mixture containing 50 mole% propane, 30% n-butane, and 20% isobutane is stored in a rigid container at 77°F. The container has a maximum allowable working pressure of 400 psig. The head
A correlation for methane solubility in seawater is given by the equation where β is volume of gas in mL at STP per unit volume (mL) of water when the partial pressure of methane is 760 mm Hg,
State whether you would use Raoult’s law or Henry’s law to perform vapor–liquid equilibrium calculations for each component in the following liquid mixtures: (a) Water and dissolved
Nitric acid is a chemical intermediate primarily used in the synthesis of ammonium nitrate, which is used in the manufacture of fertilizers. The acid also is important in the production of other
A fuel gas containing methane and ethane is burned with air in a furnace, producing a stack gas at 300°C and 105 kPa (absolute). You analyze the stack gas and find that it contains no unburned
In the final stage of the manufacturing process for a solid organic product, the product is cleaned with liquid toluene and then dried in a process whose flowchart is shown on the next page. The
You were recently hired as a process engineer by a pulp and paper manufacturing firm. Your new boss calls you in and tells you about a pulp dryer designed to reduce the moisture content of 1500
A gas stream containing 40.0 mole% hydrogen, 35.0% carbon monoxide, 20.0% carbon dioxide, and 5.0% methane is cooled from 1000°C to 10°C at a constant absolute pressure of 35 atm. Gas enters the
Recovery of a solvent vapor from a gas stream by condensation can be achieved by cooling the gas, by compressing it, or by a combination of these operations. The greater the compression, the less
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