75.9k views
1 vote
A student observes that the water in today's lab is boiling at 96 c. how do explain this, since the water's normal boiling point is 100 c?

User Rodger
by
8.9k points

1 Answer

5 votes

Final answer:

The boiling point of water can vary depending on atmospheric pressure; below 1 atm, water boils at less than 100°C. Atmospheric pressure differences likely caused the observed boiling point of 96°C in the lab.

Step-by-step explanation:

The observation that water is boiling at 96°C is an indication that the conditions during the student's lab experiment are different from the standard conditions in which water boils at 100°C. The normal boiling point of water is indeed 100°C at a pressure of 1.00 atm (atmospheric pressure). However, the boiling point can change with variations in atmospheric pressure, a phenomenon explained by the kinetic molecular theory. At pressures lower than 1 atm, water will boil at temperatures lower than 100°C because the atmospheric pressure is not as great, which requires less energy for the water molecules to escape from the liquid into the gaseous state. Conversely, water would boil at a temperature higher than 100°C if it was subjected to pressures above 1 atm. This explains why the boiling point is different in the student's experiment.

An example of a liquid that boils at a temperature higher than the boiling point of water is ethylene glycol, which boils at around 197°C.

User Amir Kaftari
by
8.5k points