if S8 has a partial pressure of .25 atm an decomposes to 4S2, is it the same partial pressure?

(In case this is relevant, temp is 1325K ata an initial pressure of 1.00 atm and both are gas)

I wonder if you have copied the question exactly as it has been presented to you. I ask because I don't understand how the initial pressure is 1.00 atm but the S8 has a partial pressure of 0.25 atm.

This is how the question is on my homework, so I don't know. Maybe to get the partial pressure of 4S2?

To determine if the partial pressure of S8 is the same before and after it decomposes into 4S2, we need to use the concept of the ideal gas law and the stoichiometry of the reaction.

First, let's write down the balanced chemical equation for the decomposition of S8:

S8(g) -> 4S2(g)

According to the ideal gas law, the partial pressure of a gas is directly proportional to its number of moles, given constant volume and temperature. So, to compare the partial pressures, we need to consider the moles of S8 and 4S2 before and after the reaction.

Let's assume we have 'n' moles of S8 initially. Since the initial pressure is 1.00 atm, the partial pressure of S8 is also 1.00 atm.

During the reaction, each mole of S8 decomposes to form 4 moles of S2. Therefore, at the end of the reaction, we will have 4n moles of S2.

Now, let's find the partial pressure of S2 at the end of the reaction. To do this, we need to consider the total number of moles of gas present and the total pressure.

Initially, we had 'n' moles of S8. After the reaction, we have 4n moles of S2. So, the total number of moles of gas at the end of the reaction is (n + 4n) = 5n.

According to the ideal gas law, assuming constant temperature, the partial pressure of S2 is given by:

P(S2) = (n(S2) / n(total)) * P(total)

where P(S2) is the partial pressure of S2, n(S2) is the number of moles of S2, n(total) is the total number of moles of gas, and P(total) is the total pressure.

In this case, n(S2) = 4n (the number of moles of S2), and P(total) = 1.00 atm (the initial total pressure).

Substituting these values into the equation, we get:

P(S2) = (4n / 5n) * 1.00 atm
= (4/5) * 1.00 atm
= 0.80 atm

Therefore, the partial pressure of S2 at the end of the reaction is 0.80 atm.

To answer the original question, the partial pressure of S8 before the reaction was 1.00 atm, and the partial pressure of S2 after the reaction is 0.80 atm. So, the partial pressure is no longer the same.