Absolute zero results in a temperature of 0 Kelvins or -273.15° Celsius. 2) What is entropy? Explain why liquids are more disordered than solids and why gases are more disordered than liquids? (2 Marks) Ans: Entropy is the measure of the disorder or randomness of energy and matter in a system. The disorderliness of liquids and gases are caused by their particles which are more separated from each other compared to the molecules or particles of gases. 3) Predict whether entropy increases or decrease for the following reaction and explain why. (Do not calculate entropy): a. CaCO3(s) > CaO(s) + CO2(g) Ans: Increase b. N2(g) + 3H2(g) -2NH3(g) Ans: Decrease c. NH4NO3(s) > NH4+(aq) + NO3?(aq) Ans: Increase d. H2O(g) - H2O(l) Ans: Decrease (4 Marks) 4) Calculate ?S for the following reaction, using the thermodynamic data provided. Ans: ?S = S(products) – S(reactants) a. NaCl(s) > Na+(aq) + Cl?(aq) ?S = (51.2 + 223.5 ) – (72.1) = 202.6 kJ/mol b. 2NO(g)+O2(g) > N2O4(g), ?S = (219.9) – [2(211.2) + 205.1] = -407.6 kJ/mol c. CH4(g) + 2O2(g) > CO2(g) + 2H2O(l). ?S = [213.7 + 2(69.9)] – [186.3 + 2(205.1)] = -243 kJ/mol d. ...

The temperature of a system rises by 45°C during a heating process. Express this rise in temperature in Kelvins. Ans: °Kelvin = °Celsius + 273 = 45°C + 273 = 318°C d. The temperature of a system rises by 180°F during a heating process. Express this rise in temperature in R, K and °C. Ans: 180°F = 82.22°C = 355.22°K = 639°R 6) The mass flow rate is 4kg/s, the heat of combustion for C3H8 is 46 450kJ/kg. Determine the heat release rate. (1 Mark) Ans: Heat release rate = heat of combustion * mass flow rate = 46 450 * 4 = 185800 kJ/s 7) What is Fourier’s Law? Mathematically express Fouriers Law defining all the terms used within it. What is thermal conductivity? Compare the values of thermal conductivity of metals, insulating materials and gases. Why does Fourier's law have a minus sign? (8 Marks) Ans: Heat flow, dQ/dt, through a homogeneous solid is directly proportional to the area, A, of the section at right angles to the direction of heat flow, and to the temperature difference along the path of heat flow. Mathematically, where dQ/dt = heat flow rate; A = area of the section; dT/dx = rate of change of temperature along the path of the heat flow; ? = proportionality constant 8) Explain the Stefen-Boltzman Law. What is emissivity? What are the range of values for the emissivity of a surface? Define the terms “black surface” and “grey surface”. What role does the view factor play in determining the rate of heat transfer? What is a blackbody? (8 Marks) Ans: The Stefen-Boltzman Law states that “[in a black body], the emissive radiations or radiating heat flux is proportional to the 4th power of temperature on the absolute scale (Kelvin).” This means that for every Kelvin degree increase in temperature of a black body,
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