51 Determine the vapor pressure of ethanol at 90.°C. 
150kPa + or -2kPa
52 Explain, in terms of particle arrangement, why a sample of solid NaCl
has less entropy than a sample of aqueous NaCl. 
arrangement in NaCl(s) is less random.
53 Determine the molecular formula for a compound that has the empirical
formula CH2O and a molar mass of 120. grams per mole. 
Work (not required)
CH2O => 12+2+16=30g/mol
120/30= 4......4 x
54 A student drew the Lewis electron-dot diagram below to represent
Explain why this diagram is not an accurate representation for the
bonding in NaCl. 
charges are not shown.
That is a molecular
structure and NaCl is ionic.