1 Chemistry is the science that investigates and explains the structure and properties of matter.

2 Chapter 1 Matter key Terms matter, mass Properties, qualitative, quantitative substance, compound, element, chemical symbol heterogeneous & homogeneous mixture, solution Solute, solvent, aqueous solution, alloy physical property, physical change phase, distillation chemical property, chemical change/reaction law of conservation of matter Endothermic, exothermic

3 Matter Matter is anything that has mass and occupies space. Mass is the measure of the amount of matter that an object contains. (The quantity of matter can be measured by determining the amount of matter.)

4 Observations of the composition of matter are based on a macroscopic view (large enough to be seen) The world of atoms is submicroscopic (too small to be seen under the microscope) The trick is to deduct the submicroscopic world from macroscopic observations

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6 Elements and Compounds Elements are made from one type of atoms Compounds are made from more than one type of atoms. Compounds can be separated into simpler substances only by chemical means. Properties of a compound are different from those of the elements composing it. Elements are always present in the same ratio in a given compound.

7 Classify the following as element or compound þ water  gold  diamond þ ammonia  mercury  carbon dioxide Name the chemical symbol for þCarbon  Oxygen  Hydrogen  Sodium  Chlorine  Nitrogen

8 Mixtures A mixture is a combination of two or more substances that can be separated by physical methods. Heterogeneous mixtures are not uniform in composition. Homogeneous mixtures, also called solutions, have uniform properties throughout and may be gases, liquids, or solids.

9 Classify the following mixtures as either homogeneous or heterogeneous  motor oil  clear nail polish  granite  glass  air  chocolate-chip ice cream  brass (blend of copper and zinc)

10 Examples of homogeneous mixtures Alloys are solid solutions (homogenous mixtures) that contain different metals (brass, steel, bronze etc.). Aqueous solution is a homogeneous mixture where water is the solvent. Example sugar water: Sugar is the solute Water is the solvent

11 Mixture, compound or element?  motor oil  sugar  salad dressing  chlorine  air  salt water  diamond  glass  hydrogen peroxide

12 Chemical Reactions Chemical Change changes the chemical composition of a substance. Chemical Property is the ability of a substance to undergo a chemical reaction Example:iron + sulfur  iron sulfide iron + oxygen  rust Name chemical and physical properties of iron

13 Physical Property of a substance can be observed or measured without changing the substance’s composition. Examples: color, odor, hardness, boiling point, melting point, solubility, density... Physical Changes is a change of matter without changing chemical composition Examples: boiling, freezing, evaporating, breaking, splitting, cutting, crushing...

14 Distillation Examples of methods to separate mixtures Filtering Evaporating Distilling chromatography... Physical methods

15 Example MixtureCompoundExample Sugar waterwater (H 2 O) separated Physical byChemical methods into Example Substances Elements Example water and sugaroxygen, hydrogen

16 Qualitative or Quantitative Qua l itative Qua n titative L = letter (words) n = numbers

17 Exothermic and Endothermic All chemical reactions involve some sort of energy change. Chemical reactions that give off heat energy are called exothermic (exo = out) ex. dynamite Chemical reactions that absorb heat energy are called endothermic (endo = into) Ex: cooking; you need to heat up the food for it to be cooked, photosynthesis needs sunlight

18 In a chemical change (chemical reaction), reactants are converted to products. Conservation of matter: Mass is conserved in any physical or chemical change. The sum of masses of all reactants is equal to the sum of masses of all products. Example iron + oxygen  rust 112 g + ? g  160 g Assign reactants and products, how much oxygen reacted with iron?