HEATING AND COOLING CURVES

What are some things that happen as we heat a sample up? Solid Liquid Gas Melting, Evaporating

What is heat? How is heat different from temperature? Heat is a measure of kinetic energy

In chemistry heat is measure in Joules (J) Heat is dependent on mass, temperature change and

specific heat (or ability of a substance to absorb heat) Temperature is a measure of warmth or

coldness. Temperature is independent of heat Temperature is measured in Kelvin (K) or Celsius (C)

What is the heating curve?

The heating curve is a graph which represents how a sample changes phases. As heat is added over time, the sample changes temperature and phase accordingly. Thus heating curve.

How does the heating curve look?

What are the parts of the heating curve?

What are the parts of the heating curve?

What are the parts of the heating curve?

What are the parts of the heating curve?

What are the parts of the heating curve?

What are the parts of the heating curve?

Why is the curve flat at some portions?

Temperature is staying constant, but potential energy is decreasing

During this time the solid completely becomes liquid (or liquid becomes solid)

Why is the curve flat at some points?

This is called the heat of fusion (Hf) in segment BC and heat of vaporization (Hv) in segment DE.

Remember fusion is melting and vaporization is evaporation

What is heat of fusion? What is heat of vaporization? Hf is the amount of

energy needed to completely make a solid into a liquid

Hv is the amount of energy needed to completely make a liquid into a gas

Summary

The heating curve is a useful tool to show us the changes in temperature and energy as a sample is heated up. It give us detailed information about phases and phase changes of samples.