2.1 PROPERTIES OF MATTER • Describe matter by looking! • Extensive Properties – depends on the amount of matter in a sample • examples- volume and mass • b. Intensive Properties – depends on the type of matter in a sample • example – bowling ball
Identifying Substances: Substance: matter that has a uniform and definite composition Physical property: the quality of a sample that can be observed or measured without changing the substance’s composition. Hardness Color Malleability Conductivity Ductile
STATES OF MATTER Solid – definite shape definite volume – atoms vibrate in fixed position Liquid – indefinite shape definite volume – atoms are in close contact but not rigid Gas – takes shape and volume of container – atoms are active and far apart As energy in the substance increases the atoms motion increases! What is the difference between gas and vapor?
PHYSICAL CHANGES Properties of a material change but the composition remains the same. Freeze Melt Condense Break Split Grind Evaporate Sublimate How can physical changes be reversible or irreversible?
2.2 MIXTURES Mixture – a physical blend of two or more substances Heterogeneous – uneven mixture composition Homogeneous – even mixture composition What is a phase?
SEPERATING MIXTURES Filtration Distillation Magnetism
2.3 ELEMENTS AND COMPOUNDS Element – simplest form of matter and cannot be broken down into simpler substances. Compound – a substance that contains two or more elements chemically combined in a fixed proportion and it can be broken down into simpler substances by chemical means
Chemical Change: If a substance takes on new properties from the combination or separation of element in the substance Heat is a good catalyst – what is a catalyst? What might give you a clue a chemical change has occurred?
SYMBOLS AND FORMULAS Symbols – one or two letters used to identify an element Formulas – a shorthand way to identify a compound or molecule
CONSERVATION OF MASS The mass of the product always equals the mass of the reactants so in any physical or chemical change mass is conserved.