Date post: | 01-Apr-2015 |
Category: |
Documents |
Upload: | german-allan |
View: | 221 times |
Download: | 4 times |
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