Question

Consider the heating curve for water.

A graph of the heating curve for water has time in minutes on the horizontal axis and Temperature in degrees Celsius on the vertical axis. A line runs through the following points: 0 minutes, negative 20 degrees; 0.5 minutes, 0 degrees; 2 minutes, 0 degrees; 4 minutes, 100 degrees; 8 minutes, 100 degrees; 9.5 minutes, 160 degrees.

At what temperature does the solid start melting?
–20°C
0°C
20°C
80°C

Answer 1

0°C

The plateau from 0.5 to 2 minutes at 0°C shows the temperature stays constant during the phase change, so the solid (ice) begins melting at 0°C.