Water flowing at a rate of 0.03 kg/s is heated from 20 to 40°C in a horizontal pipe (inside diameter = 3 cm). The inside pipe surface temperature is 70°C. Estimate the convective heat transfer coefficient if the pipe is 1 m long. Assume forced convection conditions.  Ts is not held constant!

Properties of Water

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 without doing any calculations. For each one, provide a brief description of the property listed.

(b) A thermometer is mounted on the back porch of your house. What temperature would it read for the air described in this problem?

(c) A sample of outside air is cooled at constant pressure. At what temperature would condensation begin?

(d) You step out of your neighborhood pool and feel quite cold until you dry off. Explain why. Estimate your skin temperature while you were still wet. Explain your answer. What would be different if the relative humidity were 98%?

4. The next question has to do with the condensation of water a. When water condenses on your glass, does it cool or warm the drink? b. If a can of soda at 1.0 °C has 6.512 grams of water condense on the outside, how much energy was transferred? The heat of condensation of water is 2.26kJ/g. c. If all the energy came from the soda, and the soda has the same heat capacity as water, what is the final temperature of the soda in °F?

5. A 5.69 g sample of copper metal was heated in boiling water to 99.8°C. Then it was dropped into a beaker containing 100.0 g of H2O at 22.6°C. Assuming the water gained all the heat lost by the copper, what is the final temperature of the H2O and Cu? The specific heat of water is CP=4.184 J/g∙°C and the specific heat of copper is CP,Cu=0.386 J/g∙°C

Methanol is synthesized by the gas phase reaction: Stoichiometric amounts of CO and H2 are mixed in an evacuated vessel (i.e. no methanol is present initially), and the reaction is allowed to come to equilibrium. Calculate the equilibrium mole fraction of methanol under the following conditions.

CO+2H₂-> CH₃OH

(c) The equilibrium temperature and pressure are 365 K and 1 atm, the mixture behaves as an ideal gas and a more accurate description of the temperature dependence of the equilibrium constant is available where T is in K. ln K = 21.8158+9,052/(T)-7.663ln(T)+5.4075x10-3 (T)-5.75x10-7 (T2 )-6.75x103 /(T2 )

Consider the daytime production of nitric acid from the reaction of OH^. radical and NO₂ in the gas phase. The chemistry is given below with a rate coefficient of 16 ppbV^-1 min^-1.

OH^. + NO₂ -> HNO₃

During the daytime, OH^. concentration is 4x10^-4 ppbV. If we start with 50 ppbV of nitrogen dioxide and nitrogen dioxide does not get replenished, how much nitric acid has been formed after one hour?

A hexagonal close-packed cell is known to contain two atoms of the same type located at the positions of (0,0,0,) and (1⁄3,2⁄3,1⁄2). Compute the structure factor F_hkl.

The specific enthalpy of liquid n-hexane at 1 atm varies linearly with temperature and equals 85.8 kJ/kg at 30.0 °C and 189.8 kJ/kg at 50.0 °C.

Determine the the constants a and b in the equation H∧ (kJ/kg) = a + b T (°C).

Determine the constants c and d in the equation H∧ (kJ/kg) = c[T (°C) – d].

What is the reference temperature for H∧ ?

Determine the values of e and f in the expression for U∧ (kJ/kg) = e + f T (°C).

Calculate the heat transfer rate required to cool liquid n-hexane flowing at a rate of 20.0 kg/min from 70.0 °C to 35.0 °C at a constant pressure of 1 atm. Estimate the change in internal energy (kJ/kg) as the n-hexane is cooled at the given conditions.

A settling tank treating 5.5x10*6 L of water per day has dimensions as follows: length, 12.2m; width, 7.0m; depth, 3.5m. Calculate the detention time of water in the tank? Calculate the minimum particle (expressed as diameter of spheres) size that could settle the tank?

(Q1) Explain the applications of the stability of the phases.

A system may follow various paths while going from one state to another.

Depending on the path followed, the process may be isochoric, isobaric, isothermal, or adiabatic.

You are supposed to analyze the evacuation of an uninsulated, high-pressure rigid tank filled with a gas at ambient temperature by:

(a) Drilling a very small hole on the surface of the tank.

(b) Turning on a very large valve placed on the top of the tank.

explain which process the gas remaining in the tank undergoes in these two cases above.

A2. Below are the chemical structures of fat, vitamin C, and THC (the active ingredient in the drug marijuana). The fat and THC molecules contain lots of carbon atoms, which makes them very nearly nonpolar. Chemicals that are fat-soluble are retained in fat cells for long periods of time. Chemicals that are water-soluble are quickly excreted by the body. Explain the following: (a) A person who uses marijuana will test positive for THC for several weeks after using this drug. Why? (b) The recommended daily allowance of vitamin C is 3 g/day. Why should vitamin C be consumed every day?

As you know, it takes energy to separate mixtures. You will learn this in more detail in the separations course. The idea is simple, if it takes work to separate mixtures, we should be able to produce work by making mixtures! The next question is where can we find large size streams to mix to produce significant work? The answer is simple too. Let’s go where the rivers meet the ocean! Suppose we wish to extract work when fresh river water flows into the ocean. Analyze this possibility by exploring potential ways of extracting some of the mixing energy into useful work. Once you have some ideas of how to do it, perform the actual analysis for a river of your choice in the United States. Do all the necessary calculations using appropriate thermodynamic models and make sure you estimate the maximum theoretical work that can be extracted as well.