GATE GG-1 Geochemistry PYQs & Answers — Page 3

Questions 21–30 of 37. Imported answers require independent review unless marked reviewed.

An aqueous polyphase (L + V + solid) inclusion contains a halite daughter crystal at room temperature and pressure. Which of the given statements is CORRECT in relation to this inclusion?

Your answerChoose one option.

The salinity of the bulk aqueous fluid can be determined from the temperature of melting of ice.

The salinity of the bulk aqueous fluid can be determined from the temperature of dissolution of halite.

The density in all cases can be determined from the temperature of liquid-vapor homogenization.

The density in all cases can be determined from the temperature of dissolution of the halite daughter crystal.

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A mantle source rock melts at a time t₀ giving rise to melt (M) and residue (R). Which of the following statements is CORRECT about evolution of the (ⁱ⁴³Nd/ⁱ⁴⁴Nd) and (⁸⁷Sr/⁸⁶Sr) isotope ratio in M (that crystallized to form a rock) and R?

Your answerChoose one option.

The growth of Nd isotope ratio versus time is faster in R than M and the Sr isotope ratio grows slower in R than M.

The growth of Nd isotope ratio versus time is slower in R than M and the Sr isotope ratio grows faster in R than M.

Both the Nd and Sr isotope ratios grow at identical rates in R and M.

The growth of Nd and Sr isotope ratio in M and R would depend on the initial concentrations of Sm and Rb in the mantle source rock.

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In the given reaction,

2Fe²⁺ + 3H₂O → Fe₂O₃ + 6H⁺ + 2e⁻

consider ideal condition, take concentration of Fe²⁺ as 10⁻⁵ mol, E⁰ = 0.98 V and pH=6. The value of (2.303 × R × T)/F = 0.059 (where F is the Faraday constant). The value of Eₕ on the Fe²⁺ / hematite boundary at 25 °C is __________ V. [round off to 2 decimal places]

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The first and second dissociation constants of H₂CO₃ are 6.71 × 10⁻⁷ and 4.68 × 10⁻¹¹, respectively. If the concentration of H₂CO₃ is 1 mol and pH = 6, the ∑CO₂ in the solution (assuming ideal condition) is ______ mol. [round off to 3 decimal places]

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Which one of the following processes is associated with the emission of X-rays?

Your answerChoose one option.

alpha decay

beta decay

electron capture decay

positron decay

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Which one of the following radioisotopes has the longest half-life?

Your answerChoose one option.

⁸⁷Rb

¹⁴⁷Sm

²³²Th

²³⁸U

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The abundances of the isotopes ³⁵Cl (atomic mass = 34.9685 amu) and ³⁷Cl (atomic mass = 36.9650 amu) are 75.77 % and 24.23 %, respectively. The calculated atomic weight of Cl is ________ amu. (Round off to 3 decimal places)

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If the ΔH of formation of CaSiO₃, SiO₂ and CaO from Ca, Si and O are respectively −1635, −911 and −635 kJ/mol, the enthalpy of formation of CaSiO₃ from CaO and SiO₂ is __________ kJ/mol.

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Choose the CORRECT combination for the following two statements.

Statement I: Four elements that make up about 90% of the bulk Earth are Fe, O, Si and Mg (in decreasing order of wt % abundance).

Statement II: The four most abundant elements in the Earth’s crust (in decreasing order of wt % abundance) are O, Si, Al and Fe.

Your answerChoose one option.

Both Statements I and II are correct.

Both Statements I and II are incorrect.

Statement I is correct and Statement II is incorrect.

Statement I is incorrect and Statement II is correct.

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The value of salinity, in terms of wt.% NaCl equivalent, of an aqueous saline bi-phase liquid-vapor fluid inclusions is determined by measurement of ______ during microthermometry.

Your answerChoose one option.

last ice-melting temperature

dissolution temperature of halite

eutectic temperature

homogenization temperature

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GATE GG-1 Geochemistry PYQs

Question 40

Question 42

Question 53

Question 54

Question 3

Question 4

Question 22

Question 25

Question 33

Question 35