State Avogadro's law - Leaving Cert Chemistry - Question a - 2009

1. Gases are made up of particles (molecules, atoms) in rapid, random, straight-line motion.
2. The volume of the particles (molecules, atoms) is negligible compared to the volume of the container.

1. Real gases have intermolecular forces that attract or repel particles, whereas ideal gas assumptions neglect these forces.
2. Real gas particles occupy space which affects the volume available for movement, contrary to the assumption of point particles in ideal gases.

To calculate the number of moles, use the formula:

$n = \frac{N}{N_A}$

where:

• $n$ is the number of moles,
• $N$ is the number of atoms (1.8 x 10^24),
• $N_A$ is Avogadro's number, approximately $6.022 x 10^{23}$ molecules/mole.

Substituting the values:

$n = \frac{1.8 x 10^{24}}{6.022 x 10^{23}} \approx 3.00 \text{ moles}$