Classification of Matter CHAPTER 15 Classification of Matter

Classification of Matter ESSENTIAL QUESTIONS: WHAT IS MATTER? HOW DO WE CLASSIFY MATTER? WHAT ARE PHYSICAL AND CHEMICAL CHANGES?

Composition of Matter Properties of materials are used to classify them. The two main categories are PURE SUBSTANCES and MIXTURES

PURE SUBSTANCES A type of matter with a fixed composition. ELEMENT: a substance that contains ONE TYPE of atom: copper, carbon (graphite/diamond) and oxygen (O2)..

PURE SUBSTANCES A type of matter with a fixed composition. COMPOUND: a substance in which the atoms of two or more elements are combined in a fixed proportion: H2O, CaCO3, CO2, and NaCl. The compound properties are often different from the elements that make them

MIXTURES A type of matter with NO fixed composition. HETEROGENEOUS MIXTURES: different materials are distinguished easily: pizza, soup mix, and granite. Not all are easily recognized

MIXTURES HOMOGENEOUS MIXTURES: contains two or more gaseous, liquid or solid substances blended evenly throughout: soda, air, sea water, and vinegar. These are also known as SOLUTIONS: a homogeneous mixture of particles that are CONSTANTLY and UNIFORMLY mixed.

MIXTURES COLLOID: a mixture with particles that are larger than a solution, but not heavy enough to settle out: milk (water, sugars, fats, proteins), paint (oil, pigment, etc), fog (air, liquids), and smoke in air.

MIXTURES SUSPENSIONS: heterogeneous mixture containing a liquid in which the particles settle.

PROPERTIES OF MATTER Using physical properties to separate – sifting, sorting, using a magnet, etc. RECYCLING.

Section 15.2: PHYSICAL & CHEMICAL CHANGES OF MATTER PHYSICAL CHANGE: a change in size, shape, or state of matter. THE IDENTITY REMAINS THE SAME. These changes may involve energy changes but the properties don’t change. E.g. iron when heated.

PHYSICAL & CHEMICAL CHANGES OF MATTER PHYSICAL CHANGE: a change in size, shape, or state of matter. THE IDENTITY REMAINS THE SAME. DISTILLATION – Uses a physical change to separate (evaporation). Used in industry.

CHEMICAL PROPERTIES & CHANGES CHEMICAL PROPERTY – A characteristic of a substance that indicates whether it can undergo a certain chemical change. E.g. flammable, changes color.

CHEMICAL PROPERTIES & CHANGES CHEMICAL CHANGE – produces heat, light, sound, color change, precipitate, and gas bubbles.

PHYSICAL & CHEMICAL CHANGES FOR EXAMPLE: WEATHERING Physical – rocks broken apart by ice, streams carving away rock, wind moving sand Chemical – Limestone (CaCO3) changes to gypsum in acid