# Final Pressure of Mixed Gases at 25°C

• stacker
P1 and P2 are initial pressureV1 and V2 are initial volumeSubstituting the values given,P=(271.78*2 + 372.79*1)/(2+1)P=305.78 torrIn summary, after mixing two separate flasks with gases at 25 degrees Celsius, the final pressure would be 305.78 torr. This is calculated by using the equation P=(P1V1+P2V2)/(V1+V2), where P is the final pressure, P1 and P2 are the initial pressures, and V1 and V2 are the initial volumes.
stacker
Two separate flasks are each filled with a gas at 25 degrees Celsius; the valve between them is opened and the gases are allowed to mix. What would be the final pressure in torr after mixing, if initially F2 is in the first flask (Volume = 2 L) at 271.78 torr and N2 is in the second flask (Volume = 1 L) at 372.79 torr?
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Here's my approach. I will determine the moles of F2 and N2 using the PV = nRT equation. This equation will give me the two mole values. Then I will use the fact that Xa = (na/ntotal) = Pa/Ptotal

Doing this, I got the answer to be 0.6028618419 in atm and 458.1749998 torrs.

Could someone confirm or correct me please.

Last edited:

sorry i didnt understood you my way of approach will be total no of moles are constant at const. temp
Hence P=(P1V1+P2V2)/(V1+V2) where P is final pressure after mixing

Your approach is correct. To determine the final pressure after mixing, we can use the ideal gas law equation:

PV = nRT

Where:
P is pressure (in atm)
V is volume (in L)
n is moles
R is the ideal gas constant (0.0821 L*atm/mol*K)
T is temperature (in K)

First, we need to convert the initial pressures from torr to atm:

271.78 torr = 0.359 atm
372.79 torr = 0.490 atm

Next, we can use the ideal gas law to calculate the moles of F2 and N2 in each flask:

nF2 = (0.359 atm * 2 L) / (0.0821 L*atm/mol*K * 298 K) = 0.00885 moles
nN2 = (0.490 atm * 1 L) / (0.0821 L*atm/mol*K * 298 K) = 0.00607 moles

Now that we have the moles of each gas, we can calculate the total moles and the mole fraction of each gas:

ntotal = 0.00885 moles + 0.00607 moles = 0.01492 moles
Xa = (0.00885 moles / 0.01492 moles) = 0.593
Xb = (0.00607 moles / 0.01492 moles) = 0.407

Finally, we can use the mole fractions to calculate the final pressure:

Pfinal = Xa * Ptotal
Pfinal = (0.593 * 0.359 atm) + (0.407 * 0.490 atm) = 0.214 atm

Converting back to torr, the final pressure is 0.214 atm * 760 torr/atm = 162.7 torr.

Therefore, the final pressure after mixing would be 162.7 torr. Your answer of 458.1749998 torr seems to have a calculation error.

## 1. What is the "Final Pressure of Mixed Gases" at 25°C?

The "Final Pressure of Mixed Gases" at 25°C refers to the total pressure exerted by a mixture of gases when they are combined at a constant temperature of 25°C. This pressure is a result of the combined individual pressures of each gas in the mixture.

## 2. How is the "Final Pressure of Mixed Gases" calculated?

The "Final Pressure of Mixed Gases" can be calculated using the ideal gas law, which states that the pressure of a gas is directly proportional to its number of moles, temperature, and volume. By knowing the individual pressures, volumes, and number of moles of each gas in the mixture, we can calculate the total pressure using this equation: P(total) = (n1 + n2 + ... + nN)RT/V.

## 3. Why is temperature important in determining the "Final Pressure of Mixed Gases"?

Temperature plays a crucial role in determining the "Final Pressure of Mixed Gases" because it affects the average kinetic energy of the gas molecules. As temperature increases, the molecules move faster and collide more frequently, resulting in a higher pressure. At a constant volume, an increase in temperature will lead to an increase in the final pressure of the gas mixture.

## 4. What is the unit of measurement for "Final Pressure of Mixed Gases"?

The unit of measurement for "Final Pressure of Mixed Gases" is usually in pascals (Pa) or atmosphere (atm). Other common units include kilopascals (kPa) and millimeters of mercury (mmHg). Scientists and engineers often use the SI unit of pressure, which is the pascal, while atmospheric scientists may use units such as millibars (mb) or inches of mercury (inHg).

## 5. How does the "Final Pressure of Mixed Gases" change when gases with different properties are mixed together?

The "Final Pressure of Mixed Gases" will change based on the individual properties of the gases in the mixture, such as their molecular weight, temperature, and number of moles. For example, if gases with high molecular weights are mixed with gases of low molecular weights, the final pressure will be lower than if all the gases had similar molecular weights. Additionally, if gases with different temperatures are mixed, the final pressure will be affected by the average temperature of the entire mixture.

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