Answer:

Explanation:
Hello,
In this case, the molar enthalpy of reaction is obtained by dividing the involved energy by the reacting moles:

Thus, it is important to notice that the compound "uses" the energy, it means that it absorbs the energy, for that reason the sign is positive. Moreover, computing the result in kJ/mol we finally obtain:

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Frequency.
The equation to find the velocity of a wave length is:
v=fλ
V stands for velocity
F stands for frequency
λ stands for wavelength
Answer: options B,D and F
Explanation:
Since redox reactions are those which involves both oxidation and reduction
In B , Cu is oxidized and S gets reduced
D, Na gets oxidized and hydrogen gets reduced
F, carbon gets oxidized and Oxygen gets reduced
In g, there is no change in oxidation no of s in both product and Reactants is same +4
Similarly in the case of Ag and Mg.