Chapter 2 Matter & Change

Matter Anything that has mass & takes up space All materials you hold or touch Air you breathe

Mass = a measure of the amount of matter an object contains Volume = measure of the space occupied by an object Substance = type of matter with a fixed composition (can be an element or a compound)

Physical Properties Quality or condition of a substance that can be observed or measured without changing the substances composition color, shape, odor, texture, density

Intensive Properties Physical properties depend upon the type of matter in a sample, not the amount, it helps you determine what a substance is Melting point, Density, Viscosity, Color Every sample of a given substance has the identical intensive properties because every sample has the same composition

Extensive Properties Physical properties that depend upon the amount of matter in a sample on hand & do not help you determine what a substance is Mass Length Volume

This blue crystal has a mass of 0.32g and a density of 3.20 g/cm 3. It is not malleable and has a volume of 0.1 cm 3 Which properties listed are intensive? 3.2 g/cm 3, not malleable, blue Which properties listed are extensive? 0.32g, 0.1cm 3

Physical Change Properties of a material change; however, the composition of the material does not change Occurs in a substances if there is a change in state but not change in the identity of the substance Can be reversible - melting, boiling Can be Irrevers ible - s licing, cutting

States of Matter: Solid Particles are in a fixed position – therefore, they have a rigid structure Particles have almost no freedom to change position; they change position around a fixed point Not easily compressed Definite shape Definite volume

States of Matter: Liquid Particles are close together and move freely around each other Indefinite shape but a definite volume Liquids vary in viscosity (the resistance of a fluid to flow – thickness) Not easily compressed Fixed volume, no fixed shape. Liquids take the shape of their container as far as the fixed volume goes

States of Matter: Gas Indefinite shape, indefinite volume Takes the same shape and volume as its container – spreads out to completely fill it Particles expand to fill available space, move constantly and rarely stick together Particles more very fast Gas exerts pressure (force exerted per unit area of a surface) and will escape its container if possible – balloons, propane tanks, gas grills Easily compressed

Mixture a combination of two or more substances that are physically mixed but not chemically combined Two or more substances in different proportions Can be separated by physical methods

Homogeneous Mixture contains two or more gases, liquids, or solids that are blended evenly throughout Different parts of the mixture are not visible Brass is a mixture of copper and zinc

Scuba Breathing Mixtures Breathing mixtures for scuba are homogeneous mixtures. Some examples are Nitrox (O 2 and N 2 gases) Heliox (O 2 and He gases) Trimix (O 2, He, and N 2 gases)

Heterogeneous Mixture a mixture in which different materials can be distinguished easily The composition varies from one part of the mixture to another Fruit salad, trail mix, granite

Which is which? HeterogeneousHomogeneous P

Separating Mixtures Filtration = separates a solid from the liquid in a heterogeneous mixture Distillation = process used to separate dissolved solids from a liquid (boiling and then condensing) Evaporation

Pure substances Type of matter with fixed or definite composition Every sample has identical intensive properties because every sample has the same composition Compounds Elements

composed of one type of atom substance that cannot be broken down into simpler substances Include Copper, Cu Lead, Pb The element copper consists of only copper atoms

Compound two or more elements that are chemically combined in a definite ratio such as Hydrogen peroxide H 2 O 2 Sodium chloride NaCl Dihydrogen monoxide H 2 O can be broken down into simpler substances

Chemical Properties of Matter The way a substance reacts with another to form a new substance with different properties Involve reactivity – ability of a substance to combine chemically with another substance Chemical properties of compounds vary from the individual elements that they are made from

Chemical Changes changes in composition atoms are changed or rearranged to form a new substance with new chemical properties and new physical properties bumper with rust

Law of Conservation of Mass Mass can not be created or destroyed Total mass of all matter stays the same as before the change – it changes from one form to another From ice to liquid to gas, it will all have the same mass

Molecules Molecule  smallest unit of a substance that exhibits all of the properties characteristic of that substance

Chemical Formula Chemical shorthand that uses symbols and numbers indicating the elements in a compound and their ratios C 6 H 8 N 4 O 2  Theobromine (chocolate) C 6 H 12 O 6  Fructose (sugar)

The End