Question

a pure solid sample of substance x is put into an evacuated flask. the flask is heated at a steady rate and the temperature recorded as time passes. here is a graph of the results: use this graph to answer the following questions: what is the melting point of x? ☐ °c

Explanation:

Step1: Identify the melting plateau

In a heating curve for a pure substance, the melting point is the temperature at which the substance changes from solid to liquid, corresponding to the horizontal (plateau) region of the graph where temperature remains constant while heat is added.

Step2: Read the temperature at the melting plateau

Looking at the graph, the first horizontal plateau (where the substance melts) occurs at a temperature of \(150^\circ \text{C}\) (since the temperature axis shows markings, and the plateau is aligned with \(150^\circ \text{C}\) on the temperature scale).

Answer:

\(150\)