Chapter 2 Matter and Change

Matter and Change 2.1 – Properties of Matter 2.2 – Mixtures 2.3 – Elements and Compounds 2.4 – Chemical Reactions

Objectives Differentiate and give examples of extensive and intensive properties Distinguish the three primary states of matter Distinguish physical from chemical change. Classify mixtures as homogeneous or heterogeneous. Distinguish between elements and compounds. Memorize the 24 most encountered elements names and symbols. Distinguish chemical from physical properties

Extensive Properties Mass - amount of matter of an object. Volume - the space occupied by an object. Extensive Property - a property that depends on the amount of matter in a sample.

Intensive Properties a property that depends on the type of matter, not the amount of matter. Example: Hardness of a rock Boiling point

Substances Matter that has a uniform and definite composition

Physical Properties Can be observed or measured without changing the composition of a substance Can be used to identify substances Examples: Hardness Color Malleability Boiling Point

Identifying Substances

Physical Changes Some properties of the material may change, but the composition stays the same Can be reversible or irreversible Examples: Boil Freeze Break Crush

States of Matter Solid Liquid Gas Definite shape and volume Particles are highly organized and packed close together Not easily compressed Liquid Definite volume; takes the shape of its container Particles are tightly packed together, but arranged randomly Gas Takes the shape and volume of its container Particles are spaced very far apart Easily Compressed

States of Matter

Vapor the gaseous state of a substance that is generally a liquid or solid at room temperature

Classification of Physical Changes some properties of a material change the composition of the material remains the same

24 Common Elements Carbon C Aluminum Al Copper Cu (from cuprum) Fluorine F Bromine Br Iron Fe (from ferrum) Hydrogen H Calcium Ca Lead Pb (from plumbum) Iodine I Chlorine Cl Mercury Hg (from hydrargyrum) Nitrogen N Helium He Potassium K (from kalium) Oxygen O Lithium Li Silver Ag (from argentum) Phosphorus P Magnesium Mg Sodium Na (from hatrium) Sulfur S Silicon Si Tin Sn (from stannum)

Mixture physical blend of two or more components heterogeneous mixture – composition is not uniform throughout (2 or more phases/part) homogeneous mixture – the composition is uniform throughout is a (single phase/part) Also known as a solution.

Separating Mixtures Filtration - separates a solid from the liquid in a heterogeneous mixture Distillation – a liquid is boiled to produce a vapor that is then condensed into a liquid.

Elements vs. Compounds element – the simplest form of matter that has a unique set of properties. compound – a substance that contains two or more elements chemically combined in a fixed proportion. Properties of the individual components are different than the properties of the compound

Distinguishing Substances & Mixtures The flow chart summarizes the process for classifying matter. Any sample of matter is either an element, a compound, or a mixture. Interpreting Diagrams What is the key difference between a substance and a solution?

Chemical Reactions Chemical Property ability of a chemical to undergo a chemical change Reactant – substances that undergo change Products – New substances Chemical Change – a substance changes composition and becomes something different

Chemical Changes Evidence of a change produces matter with a different composition than the original matter Evidence of a change Energy Transfer Color Change Production of gas Production of a precipitate Energy Transfer – heat (gets hot or cold), light, sound Precipitate – a solid that settles out of solution

Law of Conservation of Mass Matter is neither created or destroyed; it is only changed Mass of the products = Mass of the reactants