Can the Lever Rule be Modified for a Three-Component Problem?

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In summary, the conversation discussed whether it is possible to solve a problem with more than two components, using a specific example of dividing a quantity of 12500 units into three parts. The problem involves two linear equations and the condition that the variables are positive, which can result in an infinite number of solutions. The conversation also acknowledged that this type of problem may have been overlooked in the past.
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vin300
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Is it possible or not to solve the typical kind of problem given more than two components; take this self made problem: A quantity measuring 12500 units be divided into three parts such that 15% first, 20% second and 30% third amount to 25% original, that is 3125. What would be each divided value? I'm only looking for a solution as simple as two-component problem, nevertheless may try until some level of difficulty.
 
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vin300 said:
Is it possible or not to solve the typical kind of problem given more than two components; take this self made problem: A quantity measuring 12500 units be divided into three parts such that 15% first, 20% second and 30% third amount to 25% original, that is 3125. What would be each divided value? I'm only looking for a solution as simple as two-component problem, nevertheless may try until some level of difficulty.
If I understand this correctly, you will have two linear equations with three variables, and the condition that the three variables are positive. This kind of problems normally can have an infinite number of solutions.

In your example, you have
a+b+c=12500
15a+20b+30c=312500
a>0, b>0, c>0

You can solve the two equations for b and c in terms of a, and then get bounds for a by requiring that a>0, b>0, c>0.
The solutions are (if I didn't make a computation error):
b=6250-3a/2
c=6250+a/2
Requiring b>0 gives 0<a<4166.66
 
  • #3
Yes I did reckon in a few hours time that this kind will produce infinite results, and also explains why it remained unseen. So sorry for the waste of time.
 

FAQ: Can the Lever Rule be Modified for a Three-Component Problem?

Can the lever rule be modified to account for non-ideal solutions?

Yes, the lever rule can be modified to account for non-ideal solutions by incorporating the activity coefficients of the components in the solution. This modified version is known as the extended lever rule.

How does the modified lever rule differ from the traditional lever rule?

The modified lever rule takes into account the non-ideality of the solution by incorporating activity coefficients, while the traditional lever rule assumes ideality of the solution. This allows for more accurate predictions of phase compositions in non-ideal solutions.

Can the modified lever rule be used for all types of solutions?

Yes, the modified lever rule can be used for all types of solutions, including ideal and non-ideal solutions. However, it is particularly useful for non-ideal solutions where traditional methods may not provide accurate results.

How is the modified lever rule calculated?

The modified lever rule is calculated by multiplying the mole fraction of each component in the solution by its respective activity coefficient, and then dividing by the sum of all the resulting values. This provides the weight fraction of each component in the solution.

What are the limitations of the modified lever rule?

While the modified lever rule is more accurate for non-ideal solutions, it still has its limitations. It assumes that the activity coefficients are constant throughout the entire solution, which may not always be the case. Additionally, it does not take into account other factors such as changes in temperature or pressure.

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