Use this reaction for this question:
4NH3 (g) + 202 (g) → 4NO (g) + 6H2 (g); DeltaH = -905 J.
Which statement is true about the reaction above?
A. DeltaS is negative and DeltaG is positive.
B. Delta G is positive at all temperatures.
C. DeltaG is negative at all temperatures.
D. DeltaS is negative and DeltaG is negative.
E. DeltaS is positive and Delta G is positive.
Answer is c
Plz I’m desperate
To determine the correct statement about the given reaction, we need to analyze the values of enthalpy change (ΔH), entropy change (ΔS), and Gibbs free energy change (ΔG).
The given reaction is:
4NH3 (g) + 202 (g) → 4NO (g) + 6H2 (g)
ΔH = -905 J
Enthalpy change (ΔH) indicates whether a reaction is exothermic (negative ΔH) or endothermic (positive ΔH). In this case, since ΔH is negative (-905 J), the reaction is exothermic.
Entropy change (ΔS) reflects the degree of disorder or randomness of a system. We do not have information about ΔS in the given reaction.
Gibbs free energy change (ΔG) indicates the spontaneity of a reaction. The sign of ΔG determines whether a reaction is spontaneous (negative ΔG) or non-spontaneous (positive ΔG).
From the information given, we cannot determine the exact values of ΔS or ΔG. However, we can make certain conclusions based on the information provided.
Option A: ΔS is negative and ΔG is positive - We don't have information about ΔS, and based on the negative ΔH, it is less likely that ΔS will be negative. Also, the spontaneity of the reaction cannot be determined solely from ΔH.
Option B: ΔG is positive at all temperatures - Based on the information given, we cannot determine this, as it depends on the values of ΔS and temperature.
Option C: ΔG is negative at all temperatures - We don't have enough information to conclude this based on the data provided.
Option D: ΔS is negative and ΔG is negative - We don't have information about ΔS, and we cannot determine ΔG based on the given data.
Option E: ΔS is positive and ΔG is positive - We don't have information about ΔS, and we cannot determine ΔG based on the given data.
To summarize, we cannot determine the correct statement about the reaction based on the given data.
To determine which statement is true about the given reaction, we need to analyze the values of enthalpy (ΔH), entropy (ΔS), and Gibbs free energy (ΔG) for the reaction.
ΔH represents the change in enthalpy or heat energy during a reaction. In this case, ΔH is given as -905 J, indicating that the reaction is exothermic (releases heat).
ΔS represents the change in entropy or the degree of disorder in a system. Since ΔS is not provided in the question, we cannot determine its value based on the given information. However, we can make certain conclusions based on the reaction stoichiometry.
In the given reaction, 4 moles of NH3 and 2 moles of O2 are reacting to form 4 moles of NO and 6 moles of H2. The number of moles of gas increases from 6 to 10, indicating an increase in disorder. Therefore, it is likely that ΔS for this reaction is positive (increase in entropy).
ΔG represents the change in Gibbs free energy or the amount of energy available to do useful work during a reaction. The relationship between ΔG, ΔH, and ΔS is described by the equation ΔG = ΔH - TΔS, where T is the temperature in Kelvin.
Now, let's analyze the statements:
A. DeltaS is negative and DeltaG is positive.
This statement contradicts the conclusion we made about ΔS being positive for this reaction. Therefore, this statement is incorrect.
B. Delta G is positive at all temperatures.
Since ΔH is negative for this exothermic reaction, the value of ΔG will depend on the magnitude of ΔS and temperature (T) according to the equation ΔG = ΔH - TΔS. Without knowing the value of ΔS or the temperature, we cannot conclude that ΔG is always positive. Therefore, this statement is incorrect.
C. DeltaG is negative at all temperatures.
Based on our analysis so far, we can conclude that ΔH is negative, and since ΔS is likely positive, there is a possibility that ΔG could be negative for this reaction. However, without specific values for ΔS and T, we cannot accurately determine whether ΔG is negative at all temperatures. Therefore, this statement is incorrect.
D. DeltaS is negative and DeltaG is negative.
We have determined that ΔH is negative and concluded that ΔS is likely positive. Therefore, this statement contradicts our conclusions and is incorrect.
E. DeltaS is positive and Delta G is positive.
Based on our previous analysis, we concluded that ΔS is likely positive. However, without specific values for ΔS and T, we cannot accurately determine whether ΔG is positive or negative. Therefore, this statement is incorrect.
In conclusion, none of the given statements are definitively true based on the information provided.