GATE GG-1 topic:geochemistry PYQs & Answers — Page 4

Questions 31–37 of 37. Imported answers require independent review unless marked reviewed.

With increasing activity of silica, the CORRECT order of appearance of minerals in a weathering environment with constant ratio of activities of K

and H

Your answerChoose one option.

gibbsite → kaolinite → pyrophyllite

gibbsite → pyrophyllite → kaolinite

kaolinite → gibbsite → pyrophyllite

pyrophyllite → gibbsite → kaolinite

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Which one is CORRECT for the following equilibrium reaction between quartz and magnetite: Si¹⁶O¹⁶O + Fe₃¹⁶O₃¹⁸O = Si¹⁶O¹⁸O + Fe₃¹⁶O₄ ?

Your answerChoose one option.

100 ln α = Δqtz-mag where α = K^(1/n) (K is the equilibrium constant at the specified temperature and n is a constant quantity)

100 ln α = Δqtz-mag where α = K^n (K is the equilibrium constant at the specified temperature and n is the number of exchange atomic sites)

(ln α/100) = Δqtz-mag where α = K^(1/n) (K is the equilibrium constant at the specified temperature and n is a constant quantity)

100 ln α = Δqtz-mag where α = K^(1/n) (K is the equilibrium constant at the specified temperature and n is the number of exchange atomic sites)

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Five moles of gas A (volume V1) and 3 moles of gas B (volume V2) were kept in separate containers. These two gases are completely transferred to a new container of volume V. Assume isothermal condition, and the system does only mechanical, the entropy change of the system is ____________ Joules K

. (R = 8.3 J K

mole

)

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The value of Eh corresponding to the upper limit of natural surface aqueous environment at pH of 8.0 is ____________ V.

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The most abundant radioactive isotope in the continental crust is

Your answerChoose one option.

⁴⁰K

²³²Th

²³⁵U

²³⁸U

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The Bulk Silicate Earth (BSE) is best approximated by the average

Your answerChoose one option.

enriched upper mantle composition.

mantle and continental crust composition.

depleted mantle composition.

primitive upper mantle composition.

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The standard thermodynamic data for enstatite (Mg₂Si₂O₆), quartz (SiO₂) and forsterite (Mg₂SiO₄) is given in the table below. The Gibb’s free energy of the reaction Mg₂SiO₄ + SiO₂ = Mg₂Si₂O₆ at 600 K and 1 bar is __________ J. (Assume Cₚ = 0 for all minerals in the reaction)

Mineral	ΔH°f, 298 (kJ)	S° (J K⁻¹)
Enstatite	-3090.47	132.5
Quartz	-910.83	41.5
Forsterite	-2172.2	95.1

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

GATE GG-1 topic:geochemistry PYQs

Question 19

Question 28

Question 54

Question 55

Question 25

Question 32

Question 39