Honors Magnet Chemistry Matter and Change

Important Vocabulary Matter – the “stuff” around you. Matter is everything around you. Atoms and molecules are all composed of matter. Matter is anything that has mass and takes up space. Mass- the amount of stuff in an object.

Classification of Matter States of Matter Matter can be a gas, a liquid, or a solid. Gases have no fixed shape or volume. Liquids have no shape, but they do have a volume. Solids are rigid and have a definite shape and volume.

The Properties of Matter Extensive properties – depend on the amount of matter that is present. Example – volume, mass, amount of energy in the substance Intensive properties – do not depend on the amount of matter that is present Example – melting point, boiling point, density

Substances Matter that is uniform and has a definite composition; either an element or compound; also called pure substance. Element: Definition Compound: a substance that contains two or more elements chemically combined in a fixed proportion. Can only be separated by CHEMICAL means All samples of an identical substance have the identical physical and chemical properties

Properties of Matter When a substance undergoes a physical change, its physical appearance changes. Ice melts: a solid is converted into a liquid. Physical changes DO NOT result in a change of composition.

Physical Properties Physical property – quality or condition of a substance that can be observed or measured without changing the substance’s composition Color Odor Hardness Density Solubility Melting point, boiling point, freezing point Physical state – solid, liquid, gas

Chemical Change A change that produces matter with a different composition than the original matter.

Properties of Matter When a substance changes its composition, it undergoes a chemical change: When pure hydrogen and pure oxygen react completely, they form pure water.

Indications that a chemical reaction has occurred Energy released or absorbed Color change Odor released Production of a gas Irreversibility Production of light

Law of Conservation of Mass During any chemical reaction, the mass of the products is always equal to the mass of the reactants.

Mixtures Physical blend of two or more substances Composition can vary 2 types: Heterogeneous Homogeneous

Heterogeneous Mixture Not uniform in composition Has 2 or more phases Dirt, salad, rocky road ice cream

Homogeneous Mixture Has a completely uniform composition All components are evenly distributed Consists of a single phase Called a SOLUTION

Solution – what do you think of? Can be gas, liquid, or solid!!!!!

STOP!  Up next, separation techniques!

Separating mixtures Use PHYSICAL methods Magnet, sifting, Liquid mixtures – distillation Page 47

Organic distillation Distillation

Sugar + heat carbon + water Water + electric current  hydrogen + oxygen

Is iron transforming into rust a physical or chemical change Does the substance change composition or just change appearance?

The color of sulfur is yellow.. Physical Chemical Does the substance change composition or just change appearance?

Dynamite explodes to form a mixture of gases Physical Chemical Does the substance change composition or just change appearance?

Aluminum melts at 933 K Physical Chemical Does the substance change composition or just change appearance?

Plants use CO2 to make sugar Physical Chemical Does the substance change composition or just change appearance?

Chemical Reactions One or more substances change into new substances REACTANT(S)  PRODUCT(S)  means “change into”, “produce”, “yields”

Chemical Property The ability of a substance to undergo chemical reactions and to form new substances Rusting, burning, fermenting, exploding, rotting, decomposing Iron and sulfur example