***all negative signs should be in superscript***
Consider the following reactions:
R-+ Q —> Q- + R (non-spontaneous)
S + Q- —> Q + S- (non-spontaneous)
S + T- —> T + S- (spontaneous)
R- + U —> U- + R (spontaneous)
Which of the following reactions would be spontaneous?
1) R- +T
2) R- + S
3) Q + U-
4) U + T-
To determine whether a reaction is spontaneous or not, we need to consider the concept of Gibbs free energy (ΔG).
The Gibbs free energy change (ΔG) is related to the spontaneity of a reaction. If ΔG is negative, the reaction is spontaneous, whereas if ΔG is positive, the reaction is non-spontaneous. If ΔG is zero, the reaction is at equilibrium.
The Gibbs free energy change (ΔG) can be calculated using the equation:
ΔG = ΔH - TΔS
where:
- ΔH represents the enthalpy change (the change in heat content) of the system
- ΔS represents the change in entropy (the measure of disorder) of the system
- T represents the temperature in Kelvin
If ΔG is negative, it means that the reaction is thermodynamically favorable and will proceed spontaneously.
Now, let's analyze each reaction from the given options:
1) R- + T
We don't have information about the nature of the products (whether they are positive or negative), so we cannot determine the spontaneity of this reaction.
2) R- + S
This reaction is non-spontaneous based on the given set of reactions. Combining the information provided:
- R- + Q -> Q- + R (non-spontaneous)
- S + Q- -> Q + S- (non-spontaneous)
We can conclude that R- has a tendency to dissociate from S, so the reverse reaction (R- + S) is unlikely to be spontaneous.
3) Q + U-
This reaction is spontaneous based on the given set of reactions. Combining the information provided:
- S + Q- -> Q + S- (non-spontaneous)
- R- + U -> U- + R (spontaneous)
We can conclude that Q- has a tendency to bind with U, resulting in the formation of Q and U-.
4) U + T-
This reaction is spontaneous based on the given set of reactions. Combining the information provided:
- S + T- -> T + S- (spontaneous)
- R- + U -> U- + R (spontaneous)
We can conclude that T- has a tendency to bind with U, resulting in the formation of T and U-.
To recap:
- Reaction 1) R- + T: Unable to determine spontaneity.
- Reaction 2) R- + S: Non-spontaneous.
- Reaction 3) Q + U-: Spontaneous.
- Reaction 4) U + T-: Spontaneous.
Therefore, reactions 3) Q + U- and 4) U + T- would be spontaneous.