1.) Calculate the change in pressure required to change the freezing point of a

Question

1.) Calculate the change in pressure required to change the freezing point of a hypothetical substance, Meyerinium, by 1°C. At 357 K the heat of fusion of Meyerinium is 185 J/g. At 357 K the density of liquid Meyeriunium is 0.951 g/cm3and the density of solid Meyeriunium is 1.183 g/cm3. Give your answer in bar/K with 3 significant figures.

2.) The normal boiling point of the hypothetical substance Meyerinium is 90.3°C. At this temperature vapH = 39.9 kJ/mol. To what pressure must the pressure be reduced if we want to boil Meyerinium at 25.00°C? Give your answer in torr.

*Give your best possible answer with the data given, even it is an approximate method used*

Explanation / Answer

only 1 question at 1 time please.
2.)
At normal boiling point pressure is 760 torr
T1= 90.3 oC = (273 + 90.3)K = 363.3 K
P1 = 760 torr (anything boils when pressure equals atmospheric pressure)

T2=25 oC = (273+25) K = 298 K
P2 = ?

delta H=39.9 KJ/mol=39900 J/mol

use:
ln(P2/P1) = (- delta H/R)*(1/T2 - 1/T1)
ln(P2/760) = (-39900 /8.314)* (1/298 - 1/363.3 )
ln(P2/760) = (-39900 /8.314)* (6.032*10^-4 )
ln(P2/760) = -2.895
P2/760 = 0.0553
P2= 42.04 torr

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