Classification of Matter(C2,3) Matter can be classified into two main categories, pure substances and mixtures

Pure Substances Pure substances one type of particle. Element  one type of atom examples: gold, silver, lead, and mercury. Molecules & Compounds  two or more types of atoms joined chemically. water (H2O), carbon dioxide (CO2) & sodium chloride (NaCl) Molecules & Compounds can only be separated by chemical means.

Mixtures Mixtures: loose arrangements of materials. contains two or more substances that are not chemically joined easily separated into its various components by physical means, such as filtration, distillation (boiling) or extraction. each component retains its own identity, ratio of the components can change. Mixtures can be further classified into two categories homogeneous & heterogeneous

Heterogeneous mixture: Homogeneous mixtures One phase: Uniform - the composition of the mixture is the same throughout the mixture on a microscopic level. Example  salt water. Homogeneous mixtures may look like pure substances due to their uniformity, but they are not.. Heterogeneous mixture: More than one phase: Composition NOT uniform Various components visible. Example  potting soil, oil & vinegar salad dressing.

Solutions Solutions are : Transparent with different compositions. Made of: a solute (the substance that dissolves) and a solvent (the substance that does the dissolving). When the solvent is able to dissolve a solute, the solute is soluble. When the solvent is unable to dissolve the solute, the solute is insoluble.

Alloys Alloys are: Homogeneous mixtures of two or more metals. Very useful often having better properties than those of the pure metals that they are made of. Iron is relatively soft & rusts, Add carbon & you get steel stronger. Add nickel & chromium also  is stainless steel (strong no rust) Gold is soft Add copper to make jewelry Gold is beautiful & lustrous, copper adds strength.

Mechanical Mixtures Mechanical mixtures are: Heterogeneous, (can see the different particles). Divided into three categories (based on the size of the particles). Ordinary mechanical mixtures: Different parts large & visible Ex: A sand and salt.

Suspensions Suspension: Particles may be seen (eye or microscope). If undisturbed, gravity will eventually cause the suspended particles to separate. An example of a suspension is dirty river water - after awhile, the dirt settles. Emulsifiers prevent suspensions from separating Ex egg in oil or vinegar Flour in gravy Are suspensions heterogeneous or homogeneous?

Colloids Colloid particles too small to see (even with a microscope) gravity will not cause them to separate. Colloids are heterogeneous but appear homogenous. A colloid will cause a beam of light to be scattered or bent. Tyndall Effect

Properties of Matter Physical & Chemical Physical Properties of Matter Physical properties describe what the material is like. These are visible features that can be observed (qualitative) or measured (quantitative). State – solid, liquid, gas, plasma Colour Density, viscosity Hardness, brittleness Taste, odour, texture, lustre, clarity Melting and boiling points Ductility (bendable) and malleability (able to be hammered)

Chemical Properties of Matter Chemical properties explain how a material behaves and reacts in relation to other materials. Types of bonds Reactivity Ions formed

Changes in Matter Physical & Chemical Physical change. A physical change when there is no new product formed. The particles of the starting substance are not changed. A physical change can easily be reversed.

Chemical Change In a chemical change, a new substance is formed. Clues that a Chemical Change Took Place A new colour appeared Heat or light was given off Bubbles of gas were given off A precipitate formed The change is difficult to reverse