Question

how did altitude affect the freezing, melting, and boiling points of water?
3 points
\t\t\t\tincrease\t\t\t\tdecrease\t\t\t\tstays the same
melting point\t\t\t\t○\t\t\t\t○\t\t\t\t○
boiling point\t\t\t\t○\t\t\t\t○\t\t\t\t○
freezing\t\t\t\t○\t\t\t\t○\t\t\t\t○

Explanation:

• Melting Point (Freezing Point): The melting and freezing points of water (which are the same, \(0^\circ\text{C}\) at standard pressure) depend on the substance's properties and pressure effects. For water, small changes in atmospheric pressure (like with altitude) have a negligible effect on the melting/freezing point. So the melting and freezing points stay the same.
• Boiling Point: Boiling occurs when vapor pressure equals atmospheric pressure. As altitude increases, atmospheric pressure decreases. So water needs less heat (lower temperature) to reach a vapor pressure equal to the lower atmospheric pressure, so the boiling point decreases.

Answer:

• Melting Point: Stays the same (select the "Stays the same" option for Melting Point)
• Boiling Point: decrease (select the "decrease" option for Boiling Point)
• Freezing: Stays the same (select the "Stays the same" option for Freezing)