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Solubilization.
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there is a way to calculate how the vapour pressure of a given substance varies with temperature, namely the Clausius-Clapeyron equation - it’s equation (2) on this pageif you substitute P1 = 33.2 Pa at T1 = 298 K (25 °C) and P2 = 101,325 Pa at T2 = 483 K (210 °C), you can work out ΔHvap/R and thereby calculate the pressure when T = 304 K (31 °C) -
I was carried away once again. I forgot that Xanthan Gum does not gel. I am trying to get Carrageenan.
This page does not help me much, lots of symbols. However “Clausius-Clapeyron equation” helps! With that name I found this one.
P1 = 33.2 Pa
T1 = 298 K (25 °C)P2 = 101,325 Pa
T2 = 483 K (210 °C)
ΔvapHm = 51942 J/mole OR 52 KJ/mole. There is no “R”.This one produces nearly identical result but the result is ΔHvap instead of ΔvapHm or ΔHvap/R. “R” here is fixed.
This equation looks very different to the other two. “R” here automatically appears.
Now that I have ΔvapHm = 51942 J/mole OR 52 KJ/mole, where do I input T = 304 K (31 °C)?
How very interesting! With this new knowledge I could extrapolate to other substances! -
ln(33.2 ÷ 101325) = ΔHvap/R × (1/483 - 1/298)hence, ΔHvap/R = ln(33.2 ÷ 101325) ÷ (1/483 - 1/298) = 6242.486494…let P304 be the vapour pressure at 304 K, then:ln(33.2 ÷ P304) = ΔHvap/R × (1/304 - 1/298) = -0.413446…hence, (33.2 ÷ P304) = exp(-0.413446…) = 0.661367…hence, (P304 ÷ 33.2) = 1 / 0.661367… = 1.512020…hence, P304 = 33.2 × 1.512020… = 50.2 Pa(as an aside, I really wish there were a proper way to format equations in HTML)
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And I wish my built-in Microsoft scientific calculator could do more. I thought my eyes were problematic because I could not get the same answers as yours. I had to use an online calculator; there is no ‘In’ in the Microsoft scientific calculator.
The steps to calculating vapour pressure at a given temperature is emphatically not a jest. You made it look simple and easy. I will try to use Google Spreadsheet to help me do the automated calculations and I need to only punch in the values.
‘P304’ does not refer to Cyclopentasiloxane? It is actually P-Code to mean inhale? P304 applies to any substances that evaporates?
https://www.sigmaaldrich.com/content/dam/sigma-aldrich/countries/european-images/GHS_EU_Poster.pdf
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“let P304 be the vapour pressure [of cyclopentasiloxane] at 304 K”I’d normally put 304 in a subscript, but the ‘sub’ tag doesn’t seem to work on this board
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