The characteristic which distinguishes a true solid from other phases of matter at STP is that in a true solid the particles are 1 vibrating and changing their relative positions by vibrating without changing their relative positions 2 3 motionless but changing their relative positions 4 motionless without changing their relative positions.

Background

Solids – relatively rigid, definite volume and shape. In a solid, the atoms and molecules are attached to each other. ...

Liquids – definite volume but able to change shape by flowing. In a liquid, the atoms and molecules are loosely bonded. ...

Gases – no definite volume or shape

if the concentration of products is decreased, the equilibrium will shift toward the products). add an inert gas (one that is not involved in the reaction) to the constant-volume reaction mixture: this will increase the total pressure of the system, but will have no effect on the equilibrium condition.

explanation:

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.