Answer / kangchuentat

HEAT TRANSFER - ANSWER 5.3 : Let r (dT / dr) = e, then dT / dr = e / r. T(r) = e ln r + f by integrating both sides where e and f are constants. (b) Let c = e ln a + f and d = e ln b + f. Subtracting both equations gives c - d = e (ln a - ln b) = e ln (a / b). Then e = (c - d) / [ ln (a / b) ] and f = d - e ln b. T(r) = e ln r + d - e ln b = e ln (r / b) + d = (c - d) [ ln (a / b) ] ln (r / b) + d. The answer is given by Kang Chuen Tat; PO Box 6263, Dandenong, Victoria VIC 3175, Australia; SMS +61405421706; chuentat@hotmail.com; http://kangchuentat.wordpress.com.

Question 35 – A mixture consists of benzene (B), toluene (T) and xylene (X). At a temperature of 353 K, the data of vapor pressures : B : 754.12, T : 289.71, X : 91.19. Unit is mm Hg. The pressure P is 0.5 atm. The value of k for each substance is k = (vapor pressure) / P. (a) Calculate k for B, T and X. Let L / V = 0.65. (b) By using the equation V = F / [ (L / V) + 1 ], find the value of V when F = 100, then what is the value of L?

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Question 81 - (a) In natural gas pipe sizing, the length of the pipe from the gas source metre to the farthest appliances is 60 feet. The maximum capacities for typical metallic pipes of 60 feet in length are : 66 cubic feet per hour for pipe size of 0.5 inches; 138 cubic feet per hour for pipe size of 0.75 inches; 260 cubic feet per hour for pipe size of 1 inch. By using the longest run method : (i) Find the best pipe size needed for the capacity of 75 cubic feet per hour. (ii) Estimate the suitable range of capacities for the pipe size of 1 inch. (b) The maximum capacities for typical metallic pipes of 50 feet in length are : 73 cubic feet per hour for pipe size of 0.5 inches; 151 cubic feet per hour for pipe size of 0.75 inches; 285 cubic feet per hour for pipe size of 1 inch. By using the branch method find the best pipe size needed for the capacity of 75 cubic feet per hour when the length of the pipe from the gas source metre to the appliance is 52 feet.

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Question 32 – Let 1 ^ 1 = 1, 2 ^ 2 = 4, 3 ^ 3 = 27. By using the Excel computer programming – either by Solver or Goal Seek, find the value of v for the Van der Waals equation (P – a / v ^2) (v - b) = RT where a = 18.82, b = 0.1193, P = 2, R = 0.082, T = 5000 for benzene. Describe briefly how to use Solver and Goal Seek in Excel program of computer to find the solution quickly.

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what is difference between m3 and nm3?

2 Answers   Coromandel,

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i am appearing in railway section engg. exam of chemical eng. therefore i want previous papers and study material of chemical eng.

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According to Shockley equation, the I – V characteristic of a diode is approximated by I = IS [ exp (nVD / VT) – 1 ]. For silicon, let the reverse bias saturation current IS as 0.000000000001. If n is ideality factor with value of 1.5, VT as thermal voltage drop of 0.026 V at room temperature, what is the value of current I that passes through the silicon diode in the heater of evaporator when the forward voltage drop VD = 0.026 V? Please take note that exp is the exponential function with e(1) = 2.718, e(2) = 7.389.

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Why an electromagnetic flow meter cannot be used for gases, steam and oil flow measurements?

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What is a surfactant?

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Question 51 - A batch reactor is designed for the system of the irreversible, elementary liquid-phase hydration of butylene oxide that produces butylene glycol. At the reaction temperature T = 323 K, the reaction rate constant is k = 0.00083 L / (mol - min). The initial concentration of butylene oxide is 0.25 mol / L = Ca. The reaction is conducted using water as the solvent, so that water is in large excess. (a) Let the molecular weight of water is 18 g / mol and the mass of 1 kg in 1 L of water, calculate the molar density of water, Cb in the unit of mol / L. (b) Determine the final conversion, X of butylene oxide in the batch reactor after t = 45 min of reaction time. Use the formula X = 1 - 1 / exp [ kt (Cb) ] derived from material balance. (c) Find the equation of t as a function of X.

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what is mean by reflux ratio?

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why is cross over inlet provided in a furnace?

3 Answers   Essar,

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Question 46 - In a steady state one dimensional conduction with no heat generation, the differential equation is d / dx (k dT / dx) = 0. Prove that T(x) = ax + b, where k, a and b are constants. (b) At x = 0, T = c and at x = L, T = d. Prove that T(x) = (d - c) x / L + c for boundary conditions.

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