GATE MT Laws of thermodynamics PYQs & Answers — Page 7

Questions 61–69 of 69. Imported answers require independent review unless marked reviewed.

A 1 mol piece of copper at 400 K is brought in contact with another 1 mol piece of copper at 300 K, and allowed to reach thermal equilibrium. The entropy change for this process is ______ (in J K

to three decimal places) Given: Specific heat capacity of copper (between 250 K and 500 K) is 22.6 J K

mol

. Assume that the system containing the two pieces of copper remains isolated during this process.

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The pressure (P) versus volume (V) diagram given below represents reversible isothermal curves at temperatures, T1, T2 and T3.

Diagram for Metallurgical Engineering question 4

Considering one mole of ideal gas for all the three isothermal processes, which one of the following is TRUE?

Your answerChoose one option.

T1 > T2 > T3

T2 > T3 > T1

T3 > T1 > T2

T2 < T1 < T3

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Hydrogen dissolves in Pd by the reaction H₂ = 2 [H]. At 300°C and P_H₂ = 1 atm, the solubility of hydrogen in Pd is 1.64 × 10⁴ mm³ (STP) per kg of Pd. At 300°C and P_H₂ = 0.09 atm, the solubility of hydrogen in Pd in mm³ (STP) per kg of Pd is __________ (answer up to one decimal place)

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and

are the melting points of pure metal A and pure stoichiometric oxide

, respectively, and

. The stoichiometric metal oxidation reaction

is in equilibrium at 1 atm pressure at temperature less than

. If the temperature increases, which schematic represents the correct standard free energy change versus temperature plot?

Your answerChoose one option.

Diagram for Metallurgical Engineering question 31

Diagram for Metallurgical Engineering question 31 (figure 2)

Diagram for Metallurgical Engineering question 31 (figure 3)

Diagram for Metallurgical Engineering question 31 (figure 4)

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CaCO

(s) dissociates in a closed system according to the reaction: CaCO

(s) = CaO(s) + CO

(g) Assuming the reaction is in thermodynamic equilibrium, the degree(s) of freedom, F = __________

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In primary steelmaking, dissolved oxygen (O) reacts with carbon (C) to produce CO (g), at 1 atm pressure according to the reaction: C + O = CO (g). The equilibrium constant for this reaction is

, where T is in Kelvin. Assuming Henrian activity coefficient of both O and C to be unity, the dissolved oxygen content (in wt.%) of plain carbon steel melt with 0.7 wt.% C at 1600°C is __________ (answer up to four decimal places)

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Pure metals A and B form two real binary solid solutions α and β at temperature T and pressure P. The free energy versus composition plots for both the solutions are shown below.

Diagram for Metallurgical Engineering question 41

The condition for chemical equilibrium is:

Your answerChoose one option.

Mole fraction of A in α = mole fraction of A in β and mole fraction of B in α = mole fraction of B in β

Mole fraction of B in α = mole fraction of A in β and mole fraction of A in α = mole fraction of B in β

Activity of A in α = activity of A in β and activity of B in α = activity of B in β

Activity of A in α = activity of B in β and activity of B in α = activity of A in β

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Pure orthorhombic sulfur transforms to stable monoclinic sulfur above 368.5 K. Applying Third law of thermodynamics, the value of entropy (in J K

) of transformation at 368.5 K is __________ (answer up to two decimal places)

Given: i. Entropy change associated with heating orthorhombic sulfur from 0 K to 368.5 K is 36.86 J K

. ii. Entropy change associated with cooling monoclinic sulfur from 368.5 K to 0 K is −37.8 J K

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Assuming the solid phases to be pure, the slope of line BC in the predominance area diagram schematically shown below is ________ (answer up to two decimal places)

Diagram for Metallurgical Engineering question 44

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GATE MT Laws of thermodynamics PYQs

Question 53

Question 4

Question 7

Question 31

Question 35

Question 37

Question 41

Question 42

Question 44