Consider the following equation.
fe2o3(s) + 3h2(g) → 2fe(s) + 3h2o(g)
h = 98.8 kj, and s = 141.5 j/k. is this reaction spontaneous or nonspontaneous at high and low temperatures?
a. spontaneous at high temperatures, non-spontaneous at low temperatures
b. non-spontaneous at high and low temperatures
c. spontaneous at low temperatures, non-spontaneous at high temperatures
d. spontaneous at high and low temperatures

This reaction is A. Spontaneous at high temperatures, and non-spontaneous at low temperatures.

Explanation:

Both the enthalpy change and the entropy change due to this reaction are positive. A chemical reaction will be spontaneous only if the change in its Gibbs Free Energy is negative. is the absolute temperature in degrees Kelvins.

Assume that both and doesn't change much as increases. The value of will initially be close to when is small. The sign of will depends on that of . However, is positive, so at low temperatures will be positive and the reaction will be non-spontaneous.

However, as increases, the role of entropy change becomes more significant. The sign of will eventually be the opposite of . The value of will eventually drop below zero after the value of rises above . The reaction will eventually become spontaneous.

b. accuracy of the data matters alot more than its number of digits, organization or amount of detail. quantitative observation is more accepted than the qualitative observation.