The density of a liquid is determined by the average mass of its particles and the distance between them. The mass of the particles is related to their atomic or molecular weight, while the distance between the particles is related to their intermolecular forces and the temperature of the liquid.
The density of a liquid is directly related to the number of particles in a given volume. If the particles are more tightly packed, the liquid will be denser. The packing of particles is influenced by various factors, such as the shape and size of the particles, the strength of the intermolecular forces between the particles, and the temperature of the liquid.
For example, liquids with larger and heavier particles, such as mercury, have higher densities than liquids with smaller and lighter particles, such as water. This is because larger particles occupy more space per unit volume, leading to a higher density.
The strength of the intermolecular forces between the particles also affects the density of a liquid. Liquids with stronger intermolecular forces, such as hydrogen bonding, tend to be more tightly packed and have higher densities than liquids with weaker intermolecular forces.
Lastly, the temperature of the liquid also affects its density. As the temperature of a liquid increases, the particles move faster and occupy more space, resulting in a decrease in density. Conversely, as the temperature of a liquid decreases, the particles move slower and pack more closely together, resulting in an increase in density.