IB Chemistry HL

Predict the sign of ΔS for the melting of ice at room temperature.

It is positive because melting increases the disorder as the solid crystal lattice breaks down into a more disordered liquid state with freer molecular movement.

What is entropy?

Entropy measures the randomness and disorder of a system, specifically the distribution of energy and particles among possible arrangements. A higher entropy indicates greater disorder, with a state hierarchy of Gas > Liquid > Solid.

State one reason why entropy increases when ice melts.

The ordered hydrogen-bonded structure in ice breaks down, allowing molecules to move more freely and randomly in the liquid phase.

Explain in terms of particle arrangement why entropy increases during melting.

In solid ice, water molecules are arranged in a fixed, regular lattice with limited movement. When melting occurs, molecules gain translational and rotational freedom, leading to a more disordered arrangement and increased entropy.