Question about using the Wihelmy blade method

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In summary, the Wilhelmy blade method is used to measure the interfacial tension between a paracetamol compact and water. The force measured for a contact angle of 88.29° is 0.21 mN. The surface tension is not mentioned, but the interfacial tension between the paracetamol blade and water is 58.6mN/m. The contact angle between the paracetamol blade and water is not mentioned, but it can be calculated using the equation COSθ= F/P* ƔLV.
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havenly
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Homework Statement
the wihelmy blade method
Relevant Equations
COSθ= F/P* ƔLV
for the wihelmy blade method we want to measure the interfacial tension exerted on a paracetamol compact in the shape of a rectangular parallepiped perimeter submerged 0.12 m in water we measure a force of 0.21 mN for a contact angle of 88.29°

answer whether they are true or false

Surface tension is 23 in/dyn
la tension interfaciale entre la lame de paracetamol et l'eau est 58,6mN/m
the contact angle between the paracetamol blade and the water 19.15mN/m
the contact angle between the paracetamol blade and the water is 32.15m/mNI think that the interfacial tension is 58.6mN/m because of question c I do not understand how to calculate the contact angle between the paracetamol sheet and the water
 

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  • #2
havenly said:
Homework Statement:: the wihelmy blade method
Relevant Equations:: COSθ= F/P* ƔLV

answer whether they are true or false

Surface tension is 23 in/dyn
la tension interfaciale entre la lame de paracetamol et l'eau est 58,6mN/m
the contact angle between the paracetamol blade and the water 19.15mN/m
the contact angle between the paracetamol blade and the water is 32.15m/mN
It seems to be a simple problem of converting 23 inch/dyne to meter/milliNewton.

Please, see:
https://en.wikipedia.org/wiki/Wilhelmy_plate

https://www.researchgate.net/profile/Virginija_Jankauskaite/publication/285514136/figure/fig1/AS:670019541295122@1536756515903/Schematic-representation-of-Wilhelmy-plate-method.png
 

1. What is the Wihelmy blade method?

The Wihelmy blade method is a technique used to measure the surface tension of liquids. It involves suspending a thin, flat blade onto the surface of the liquid and measuring the force required to pull it out.

2. How is the Wihelmy blade method performed?

To perform the Wihelmy blade method, a thin, flat blade is attached to a balance or force sensor. The blade is then carefully lowered onto the surface of the liquid, making sure it is parallel to the surface. The force required to pull the blade out is measured and used to calculate the surface tension of the liquid.

3. What are the advantages of using the Wihelmy blade method?

The Wihelmy blade method is a simple and accurate way to measure the surface tension of liquids. It also allows for the measurement of surface tension for a wide range of liquids, including those that are highly viscous or have low surface tension values.

4. Are there any limitations to the Wihelmy blade method?

One limitation of the Wihelmy blade method is that it can only be used for liquids that are compatible with the material of the blade. Additionally, the method may not be suitable for measuring the surface tension of liquids with high vapor pressure or those that are prone to foaming.

5. How is the Wihelmy blade method different from other methods of measuring surface tension?

The Wihelmy blade method is a direct measurement technique, meaning it directly measures the force required to pull the blade out of the liquid. Other methods, such as the drop weight method, indirectly measure surface tension by measuring the shape or behavior of a droplet on the liquid's surface.

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