Question

Use the Gizmo to find the freezing, melting, and boiling points of water at 5,000 meters (16,404 feet). Write these values below. Freezing point: _______ Melting point: _______ Boiling point: _______

Answer 1

Freezing point: 32 ºF (0ºC)

Melting point: 32 ºF (0ºC)

Boiling point: 203°F (95°C)

Step-by-step explanation:

At the boiling point, the vapor pressure of a liquid equals the external pressure. The normal melting point and boiling point of water at 1 atm are 0°C and 100°C, respectively. Decreasing the pressure under 1 atm (what happens when we are at high altitudes) will lower the boiling point since the external pressure will be lower, and it will become equal with the vapor pressure at a lower temperature.

However, the melting point and freezing point will stay unaffected since they don't depend on air-pressure; so at 0 or 5000 meters they will still be 0°C (remember that, since water is a pure substance, the freezing and melting points will be the same).