Matter

[cobigirl95]

As a solid is heated, its temperature increases from 10 C to 25 C, remains at 25 C for 5 minutes, and then increases to beyond 45 C. What conclusion can be drawn about the substance?
1) Its melting point is 45 C
2) Its boiling point is 45 C
3) Its melting point is 25 C
4) Its boiling point is 25 C

[Rev. Green]

3) because the heat being added at 25 C is being used to melt it, and so the temperature does not increase until it has melted.