Question

Below is a heating curve for a pure substance. It shows how the temperature rises over time, when the substance is heated untill it melts, then boils
A) what is the melting point of the substance?

Answer 1

Answer:

(a) At point A : The substance is in the solid state.

At point B : The substance has started melting. It exists both in the solid and liquid states.

At point C : The substance is in the liquid state.

A point D : The substance has started boiling. It exists both in the liquid and gaseous states.

(b) the melting point of the substance is 15∘C.

(c ) The boiling point of the substance is 110∘C.

(d) The temperature remains the same during the change of state.

(e ) Had substance been water, its melting point should have been 0∘C and boiling point 100∘C. It is therefore, not water.

Explanation:

Answer 2

Answer:

(a) At point A : The substancve is in the solid state.

At point B : The substance has started has started melting. It exists both in the solid and liquid states.

At point C : The substace is in the liquid state.

At point D : The substance has started boiling. It exists both in the liquid and gaseous states.

(b) The melting point of the substance is 15∘C.

(c) The melting point of the substance is 110∘C.

(d) The temperature remains the same during the chage of state.

(e) Had substance been wagter, its melting point should have been 0∘C and boiling point 100∘C. It is therefore, not water.