Question

1. use your knowledge of the kinetic molecular theory to explain the following statements: (a) solids have a definite shape because ________ (b) liquids and gases flow because ______ (c) ice cubes form in the freezer because ______ (d) ice cream melts quickly on a hot day because ______ (e) gases do not have a definite shape because ________

Explanation:

(a) In solids, molecules are closely packed and vibrate around fixed positions, giving solids a definite shape.
(b) Molecules in liquids and gases have more freedom of movement. They can slide past one - another, allowing them to flow.
(c) In the freezer, water molecules lose kinetic energy. They slow down and arrange themselves in a regular pattern to form ice cubes.
(d) On a hot day, heat is transferred to the ice - cream. The molecules gain kinetic energy, break the rigid structure, and the ice - cream melts.
(e) Gas molecules are in constant, random motion and are far apart from each other. They fill the container they are in and do not have a definite shape.

Answer:

(a) Molecules are closely packed and vibrate around fixed positions.
(b) Molecules can slide past one another.
(c) Water molecules lose kinetic energy and arrange in a regular pattern.
(d) Heat transfer causes molecules to gain kinetic energy and break the rigid structure.
(e) Gas molecules are in constant, random motion and far apart.