Matter: Properties, States, and Transformations
Properties of Matter
Matter is anything that has mass and occupies space. Properties are the characteristics of a substance. Substances can have both physical and chemical properties. Transformations are the changes that can be observed in matter over time.
States of Matter
Matter exists in three states:
- Solid: Rigid and dense with a definite shape and volume.
- Liquid: Dense and fluid, takes the shape of the container.
- Gas: Like a very low-density fluid – takes the shape and volume of the container.
Mixtures and Pure Substances
Mixture: A blend of two or more substances that still maintain their identity and there is no chemical reaction.
Pure substance: Uniform in its chemical composition and properties.
Types of Mixtures
- Heterogeneous mixtures: Contain different phases and are not uniform in appearance.
- Homogeneous mixtures: Contain only one visibly distinct phase with uniform properties throughout. Such mixtures are called solutions, especially when in liquid form.
Types of Pure Substances
- Elements: Pure substances that cannot be broken down chemically into anything simpler.
- Compounds: Combinations of elements (two or more) that can be broken down chemically into the elements.
Solutions
A homogeneous mixture that contains particles the size of a typical ion or small molecule.
Colloids
A homogeneous mixture that contains particles in the range 2–500 nm diameter.
Physical Properties of Matter
Characteristics that can be observed or measured without changing the identity or composition of the substance:
- Color
- Odor
- Taste
- Size
- Physical state
- Boiling point
- Melting point
- Density
Chemical Properties of Matter
Characteristics that describe the way the substance can change or react to form other substances.
Chemical Reactions
In a chemical reaction, we have the reactants and the products:
- Reactants: The starting materials, which can be one or more substances
- Products: One or more substances formed as a result of the reaction between the reactants.
A chemical reaction is described in a chemical equation, which is read a bit like a mathematical equation:
– One reactant plus another reactant forms (or equals) one or more products
Periodic Table and the Elements
The Periodic Table organizes the elements based on their properties and relationships to each other.
Chemical Formulas
When different elements combine together, they form compounds, which have what are called chemical formulas.
A chemical formula shows the symbols as well as the number and ratio of the atoms (or units) of the element. t here!