Physical States of Matter

States of Matter

• Matter exists in one of four states: gas, liquid, solid, and plasma.
• Gas: no fixed volume or shape, adopts the volume and shape of its container.
• Liquid: distinct volume, no specific shape.
• Solid: distinct volume and shape.
• Plasma: produced by heating gas or subjecting it to intense electromagnetic fields, composed of ions (positively and negatively charged particles).

Properties of Matter

• Shape, size, color, mass, volume, ductility, malleability, lustre (shininess), hardness (Mohs scale), boiling point (Celsius or kelvin), melting point, solubility (mass per unit volume), thermal conductivity (W m-1 K-1), and electrical conductivity (A2 s3 m-3 kg-1).

Classification of Matter

• Elements: pure substances that cannot be broken down, all atoms of a chemical element are indistinguishable from each other, most elements are solid in nature.
• There are 118 elements, including oxygen and nitrogen, on the periodic table.
• Elements can differ due to isotopes (differences in stability due to differing number of neutrons).

Compounds

• Compounds are pure substances that consist of 2 or more chemical elements combined chemically in definite proportions.
• Examples include Sodium chloride (NaCl) and water.

Mixtures

• A mixture is a non-chemical combination of 2 or more pure gas, liquid, or solid substances.
• Mixtures can be any of the 3 states and can consist of multiple phases.
• Mixtures can be either homogenous or heterogenous.
• Examples include foam (gas+liquid) and face cream (liquid+solid).

Solutions

• A solution is a homogenous mixture.
• Solutions can be solid, liquid, or gas, but consist of only a single phase.

Chemistry

• Chemistry is the study of matter and the science of explaining and quantifying observable macroscopic phenomena and properties in terms of microscopic structures and interactions.

Dalton's Atomic Theory

• Atoms are indivisible, indestructible, and always in motion.
• Dalton's atomic theory:
  • Matter consists of tiny particles called atoms.
  • Atoms are indestructible - in chemical reactions, they can be rearranged but not created or destroyed.
  • In any sample of a pure element, all atoms are identical in mass and other properties.
  • All atoms of different elements differ in mass and other properties.
  • When atoms of different elements combine to form a given compound, the constituent atoms in the compound are always present in the same fixed numerical ratio.

Chemical Equations

• Dalton's atomic theory enables us to use a shorthand language to describe chemical reactions - a balanced chemical equation.
• A balanced chemical equation consists of reactants on the left and products on the right, separated by an arrow that indicates change, with elements represented by their chemical symbol, and the physical state following each compound.

The Law of Multiple Proportions

• Whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in a simple whole-number ratio.