3. Calculate the standard entropy change for the reaction:
N2 + 3H2 → 2NH3
given the standard entropies
Sº(N2)(g) = 191.6 J K^-1 mol^-1
Sº(H2)(g) = 130.6 J K^-1 mol^-1
Sº(NH3)(g) = 193.3 J K^-1 mol^-1
dSrxn = (n*dSproducts) - (n*dSreactants)
192+3(131) >2(193.3)
192+393>386.6
585>386.6
585-386.6=198.4jkmol
Well, entropy is like the party of molecules. The more they can move around and dance, the higher the entropy. So let's see what's happening in this reaction.
Initially, we have one molecule of N2 and three molecules of H2. And after the reaction, we end up with two molecules of NH3.
So, it's like going from a small party with four people to a bigger party with two people. Less people, less movement, less entropy.
To calculate the standard entropy change, we use the formula:
ΔSº = ΣnSº(products) - ΣnSº(reactants)
ΔSº = (2 x Sº(NH3)) - (1 x Sº(N2) + 3 x Sº(H2))
ΔSº = (2 x 193.3 J K^-1 mol^-1) - (1 x 191.6 J K^-1 mol^-1 + 3 x 130.6 J K^-1 mol^-1)
ΔSº = 386.6 J K^-1 mol^-1 - 583.4 J K^-1 mol^-1
ΔSº = -196.8 J K^-1 mol^-1
So the standard entropy change is -196.8 J K^-1 mol^-1. It's negative because we're going from a higher entropy state to a lower entropy state. It seems like the molecules are going from the dancefloor to the corner of the room. Not very fun!
To calculate the standard entropy change (ΔSº) for the reaction, you can use the equation:
ΔSº = ΣnSº(products) - ΣnSº(reactants)
where Σn represents the stoichiometric coefficients of each species in the reaction, and Sº refers to the standard entropy values.
Given the reaction:
N2 + 3H2 → 2NH3
Let's calculate the standard entropy change step-by-step.
Step 1: Determine the stoichiometric coefficients
The stoichiometric coefficients in the balanced equation are:
N2: 1
H2: 3
NH3: 2
Step 2: Calculate the standard entropy change
ΔSº = [2 × Sº(NH3) ] - [1 × Sº(N2) + 3 × Sº(H2)]
Substituting the given values:
ΔSº = [2 × 193.3] - [1 × 191.6 + 3 × 130.6]
ΔSº = 386.6 - 191.6 - 391.8
ΔSº = -196.8 J K^-1 mol^-1
Therefore, the standard entropy change (ΔSº) for the given reaction is -196.8 J K^-1 mol^-1.
To calculate the standard entropy change for a reaction, you need to use the standard entropies of the reactants and products.
In this case, the reaction is N2 + 3H2 → 2NH3.
The standard entropy change (ΔSº) can be calculated using the following equation:
ΔSº = ΣnSº(products) - ΣmSº(reactants)
Where ΣnSº(products) represents the sum of the standard entropies of the products, and ΣmSº(reactants) represents the sum of the standard entropies of the reactants. n and m are the stoichiometric coefficients.
Let's calculate the standard entropy change for this reaction step by step:
Step 1: Determine the stoichiometric coefficients:
The stoichiometric coefficients in the balanced equation are:
N2: 1
H2: 3
NH3: 2
Step 2: Calculate ΣnSº(products)
For this reaction, there is only one product, which is NH3. So we can calculate ΣnSº(products) as follows:
ΣnSº(products) = 2 * Sº(NH3)(g)
Step 3: Calculate ΣmSº(reactants)
The reactants in this reaction are N2 and H2. We need to consider their stoichiometric coefficients and standard entropies:
ΣmSº(reactants) = 1 * Sº(N2)(g) + 3 * Sº(H2)(g)
Step 4: Calculate ΔSº
Using the equation ΔSº = ΣnSº(products) - ΣmSº(reactants), we can substitute the values we calculated:
ΔSº = 2 * Sº(NH3)(g) - (1 * Sº(N2)(g) + 3 * Sº(H2)(g))
Now we can substitute the given values:
ΔSº = 2 * 193.3 J K^-1 mol^-1 - (1 * 191.6 J K^-1 mol^-1 + 3 * 130.6 J K^-1 mol^-1)
Calculating this expression will give you the standard entropy change (ΔSº) for the reaction.