Janice's teacher recommended using temperature to differentiate between the alcohol and water mixture. The relevant property illustrated through this experiment is D. boiling. The boiling point is the temperature at which a liquid transitions into vapor. Water boils at 100°C under atmospheric pressure, while most alcohols have lower boiling points. Recognizing the significant boiling temperature disparity between the two substances was essential for their separation.
Assuming the water vapor behaves as an ideal gas,
PV = nRT
For conversions, 760 mmHg = 101325 Pa and 1,000 L = 1 m³
(187.5 mmHg)(101325 Pa/760 mmHg)(5 L)(1 m³/1,000 L) = n(8.314 m³Pa/molK)(65+273 K)
Calculating for n,
n = 0.0445 mole of water
Considering the molar mass of water is 18 g/mol,
The mass of the vaporized water = 0.0445 * 18 = 0.8 g of water evaporated
Therefore,
The fraction of water that vaporized = 0.8/1.2 * 100 = 66.7%
The correct answer is C: 2.0 mL. This is due to the precision of the burette, which measures liquid volumes accurately with a precision of ±0.01 mL, indicating that it can reliably measure volumes around 2 mL without issue.
