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# Heat Capacity, Enthalpy, IM Forces and Radius of Pt Atom

1.Calculate the amount of heat that must be absorbed by 10.0 g of ice at -20 C to convert it to liquid water at 60.0 C. Given: Specific heat (ice)=2.1 J/goC Specific heat(water)=4.18 J/goC H (fus)=6.0 kJ/mol
420 J
2,900 J
6,300 J
63 kJ
7.5 J

2. The major enthalpy of Boron tribromide (BBr3) is 30.5 kJ/mol, and its normal boiling point is 91oC. What is the vapor pressure of BBr3 at 20oC?
11.5 torr
311 torr
5.31 torr
143 torr
66.1 torr

3. Each of the following substances is a liquid at -50oC. Place these liquids in order of increasing vapor pressure: Dimethyl ether (CH3OCH3), propane (C3H8), ethanol (CH3CH2OH).
Ethanol<propane<dimethyl ether
Ethanol<dimethyl ether<propane
Propane<dimethyl ether<ethanol
Dimethyl ether<ethanol<propane
Propane<ethanol<dimethyl ether

4. Platinum (Pt) has a face centered cubic crystal structure and a density of 21.5 g/cm3. What is the radius of the platinum atom(pm:picometer).
69 pm
98 pm
139 pm
196 pm
277 pm

#### Solution Summary

Questions regarding heat capacity, enthalpy, intermolecular forces and finding the radius of a platinum atom are answered in detail with full explanations and working.

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