Answer: Moles of hydrogen required are 4.57 moles to make 146.6 grams of methane,
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Explanation:
Given: Mass of methane = 146.6 g
As moles is the mass of a substance divided by its molar mass. So, moles of methane (molar mass = 16.04 g/mol) are calculated as follows.

The given reaction equation is as follows.

This shows that 2 moles of hydrogen gives 1 mole of methane. Hence, moles of hydrogen required to form 9.14 moles of methane is as follows.

Thus, we can conclude that moles of hydrogen required are 4.57 moles to make 146.6 grams of methane,
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The value of ΔG° at this temperature is -18034.18 J/mol
Calculation,
Given information
formation constant (Kf)= 1.7 × 
Universal gas constant (R) = 8.314 J/K• mol
Temperature = 25° C = 25 °C + 273 = 300 K
Formula used:
ΔG° = -RT㏑Kf
By putting the valur of R,T, Kf we get the value of ΔG°
ΔG° = - 8.314 J/K• mol×300K㏑ 1.7 × 
ΔG° = -2494.2㏑ 1.7 ×
= -18034.18 J/mol
So, change in standard Gibbs's free energy is -18034.18 J/mol
Learn about formation constant
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The answer is Strontium(Sr). The reactive increase from right to left. And this element has two valence electrons. So Rb is not correct. Then the very reactive metal is Sr.
Explanation:
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