How to Calculate Total Pressure in a Chemical Equilibrium System?

• annastewert
In summary, the conversation discusses the calculation of the total pressure of gases at equilibrium in a 1.70L flask containing 0.120 mol of PCl5 at a temperature of 227∘C. The formula ΔG=-RTln(K) is used to find the equilibrium constant K, and the moles of each substance at equilibrium are determined using this value. Finally, the total pressure is calculated using the ideal gas law equation.
annastewert

Homework Statement

Introduced into a 1.70 −L flask is 0.120 mol of PCl5(g); the flask is held at a temperature of 227∘C until equilibrium is established.
PCl5(g)⇌PCl3(g)+Cl2(g)

What is the total pressure of the gases in the flask at this point? [Hint: Use data from Appendix D in the textbook and appropriate relationships from this chapter.]

Homework Equations

From the data tables I got ΔG for the following to be:
Cl2 = 0
PCl3 = -267.8
PCl5 = -305
From this I know ΔG to be 37.2.

ΔG=-RTln(K) (1)
PV=nRT (2)

The Attempt at a Solution

Using equation (1) I found K and then found the moles of each substance at equilibrium. I added these together and put them into equation (2) to get P. This isn't working for me. Is there a better way to do it?

annastewert said:

Homework Statement

Introduced into a 1.70 −L flask is 0.120 mol of PCl5(g); the flask is held at a temperature of 227∘C until equilibrium is established.
PCl5(g)⇌PCl3(g)+Cl2(g)

What is the total pressure of the gases in the flask at this point? [Hint: Use data from Appendix D in the textbook and appropriate relationships from this chapter.]

Homework Equations

From the data tables I got ΔG for the following to be:
Cl2 = 0
PCl3 = -267.8
PCl5 = -305
From this I know ΔG to be 37.2.

ΔG=-RTln(K) (1)
PV=nRT (2)

The Attempt at a Solution

Using equation (1) I found K and then found the moles of each substance at equilibrium. I added these together and put them into equation (2) to get P. This isn't working for me. Is there a better way to do it?
Show us more of the details, please.

What is the total pressure of a system?

The total pressure of a system is the sum of all the individual pressures exerted by each component in the system. It is a measure of the total force exerted on the walls of the container that contains the system.

How is the total pressure of a system calculated?

The total pressure of a system can be calculated by adding together the partial pressures of each gas present in the system. The partial pressure of a gas is equal to its mole fraction multiplied by the total pressure of the system.

Why is the total pressure of a system important?

The total pressure of a system is important because it can affect the physical and chemical properties of the system. It also plays a crucial role in determining the direction and rate of chemical reactions that take place within the system.

What factors can affect the total pressure of a system?

The total pressure of a system can be affected by changes in temperature, volume, and the amount of gas present in the system. Additionally, the presence of other substances, such as catalysts or impurities, can also influence the total pressure.

How is the total pressure of a system measured?

The total pressure of a system can be measured using various instruments, such as barometers or manometers. These devices measure the pressure exerted by the gas on a column of liquid or a flexible membrane, which can then be converted to the total pressure of the system.

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