Organic Chemistry
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Predict the entropy change (ΔS > 0, ΔS = 0, or ΔS < 0) of the following elimination step:
In which of the following reactions will ∆S° be the greatest and positive? Assume that all the species are gases.
Identify whether the standard entropy change, ΔS°, is positive, negative, zero, or impossible to predict for the reaction below:
Predict whether the ∆S° for the given reaction is expected to be less than, greater than, or equal to 0. Explain.
At room temperature the reaction between propene (CH2=CH−CH3) and hydrogen gas (H2) to form propane (CH3−CH2−CH3) goes to completion when a platinum catalyst is present in the reaction mixture.Determine the signs of ΔH° and ΔS° for this addition reaction based on the information given above. Explain these signs in terms of freedom of motion and bonding.CH2=CH−CH3 + H2 (Pt catalyst) → CH3−CH2−CH3
The hydrogenation of 2-butene to produce butane is shown below:
In terms of entropy, is the reaction favored or disfavored?
From the given reactions, determine which one has a greater ∆S°. Also, is the value positive or negative?
Consider the following equilibrium reaction:
Which direction is favored? Use the data below.
Predict the sign of ΔS° for the following reaction.
Use the bond-dissociation energies to estimate the equilibrium constant of the reaction given below at 298 K.
The dehydrogenation of ethane (CH3−CH3) to ethene (CH2=CH2) has ΔH° = +136 kJ/mol (+32.5 kcal/mol) and ΔS° = +120 J/kelvin-mol (+28.7 cal/kelvin-mol). Calculate the value of ΔG° for the reaction at room temperature. Is the reaction favored or disfavored?
Determine whether the standard entropy change, ΔS°, is positive, negative, zero, or impossible to predict for the following reaction:
Determine the value of the entropy change ((ΔS > 0, ΔS = 0, or ΔS < 0) in the following reaction:
Provide the temperature at which any value of the entropy change of a process becomes negligible in determining its spontaneity.
Determine if the ∆S° for the given reaction is expected to be less than, greater than, or equal to 0. Justify.
In the given reaction, if the temperature is increased, which side of the reaction, if any, would be favored?
Predict whether the ∆S° of sublimation of dry ice is less than, equal to, or greater than 0. Justify your answer.
Determine whether the ∆S° is less than, greater than, or equal to zero in the reaction shown below.
Consider the following ring-opening reaction of an epoxide:
What is the sign of ∆S°?
A reaction with an equilibrium constant of 2.00 × 10–5 is conducted at 25°C. To increase the equilibrium constant by a factor of 100, what is the required change in each of the following?
(i) ΔG°
(ii) ΔH°, if ΔS° = 0
(iii) ΔS°, if ΔH° = 0
The rate constants of a certain reaction at different temperatures were recorded as shown below.
Calculate the activation energy, ΔG‡, ΔH‡, ΔS‡ of the reaction at 50°C.
(I) Identify the side of the reaction that is favored by entropy. (II) And if the change in entropy (∆S°) is zero for this reaction, calculate the change in Gibbs free energy (∆G°) using the assumption of a temperature (T) of 298 K.
Analyze the provided values below to ascertain whether the reaction would be favorable or unfavorable.
∆H° = +9.45 kcal/mol ; ∆S° = +80 cal/mol•K ; T = 425 K
A reaction has an enthalpy change of +12.8 kcal/mol and an entropy change of +75 cal/mol⋅K. (a) At which temperature will the process be in a state of neither being favored nor disfavored? (b) Will the process be favored or disfavored if the temperature exceeds the calculated value? (c) And what about if the temperature is lower than the calculated value?
Determine from the given thermochemical values (∆H°, ∆S°, and T) if the reaction will be favorable or unfavorable.
∆H° = -9.2 kcal/mol ; ∆S° = -21 cal/mol•K ; T = 298 K
Assuming the T = 298 K, determine the ∆G°, ∆H°, and ∆S° for the following reaction. Base the value of enthalpy (∆H°) on the structure of the conjugate bases.
Consider a hypothetical reaction with a heat of reaction of –124 kJ/mol. At 1750 K, the amount of the products in this reaction is equal to the amount of reactants, making the value of the equilibrium constant equal to 1. Determine the ΔS for the reaction.
A chemical reaction is performed at 35°C (308 K) with ∆H° = 3.00 x 101 kcal/mol and ∆S° = 6.00 x 10-2 kcal mol-1 K-1. What is the equilibrium constant (K1) for this reaction? What would be the equilibrium constant (K2) if the same reaction was conducted at 125°C (398 K)?