Matter-Properties and Changes I will distinguish between physical and chemical properties I will classify matter by composition: element, compound or mixture I will identify observable characteristics of chemical reactions I will explain the fundamental law of conservation of mass

Properties of Matter I will identify the characteristics of a substance I will distinguish between physical and chemical properties I will differentiate among the physical states of matter

Substances Matter that has a uniform and unchanging composition Aka pure substance Example 1 Table Salt Always 100% sodium chloride Example 2 Water H2O NOT AN EXAMPLE Sea water Samples vary by location Amount of salts, water, dissolved substances

Physical Properties A characteristic that can be observed or measured WITHOUT changing the sample’s composition Density Color Odor Taste Hardness Melting point Boiling point

Examples-Physical Properties Salt (sodium chloride) Forms solid white crystals at room temperature Unique salty taste Oxygen Colorless Gas at 25 degrees Celsius Melting point -218 degrees Celsius Boiling point -183 degrees Celsius Density 0.0014 g/cc

Extensive Properties Dependent upon the amount of substance present Examples Mass Volume Length Weight

Intensive Properties Independent of the amount of the substance present Examples

Chemical Properties The ability of a substance to combine with or change into one or more other substances And/Or The inability of a substance to change into another substance Example Iron forms rust when combined with air Iron + Nitrogen (at room temperature) = no chemical change

Observing Properties of Matter Every substance has its own unique set of physical and chemical properties May vary depending on conditions of immediate environment Room temperature, standard pressure, etc. Example Copper Physical Properties Chemical Properties Reddish brown Shiny Malleable (easily shaped) Ductile (drawn into wire) Conducts heat/electricity Density 8.92 g/cc Melting Point 1085 ℃ Boiling Point 2570 ℃ Forms green copper carbonate compound when in contact w/ moist air Forms new substances when combined with nitric and sulfuric acids Forms a deep blue solution when in contact with ammonia

States of matter PHYSICAL PROPERTY!!!!! Solid Liquid Gas Plasma FUN FACT: (only occurs naturally on Earth in the form of lightening bolts!) PHYSICAL PROPERTY!!!!!

Solids A form of matter that has its own definite shape and volume. Examples Wood Iron Paper Sugar Particles are VERY tightly packed Will only expand SLIGHTLY when heated Does NOT conform to shape of container Incompressible Volume stays the same Example Wax (moldable) but volume doesn’t change

Liquids Virtually incompressible Tend to expand when heated Liquid Particles NOT rigidly held in place less closely packed than solids Are able to move past each other A form of matter that flows, has constant volume, and takes the shape of its container Examples Water Blood Mercury

Gases A form of matter that flows to CONFORM to the shape of its container and fills the ENTIRE volume of its container Examples Neon Lighted signs Methane Cooking Air Mixture of gases Particles are VERY far apart EASILY compressed A substance NATURALLY in the gaseous state at room temperature RELATED TERMS Vapor The gaseous state of a substance that is a SOLID or LIQUID at room temperature Example steam

Quick Think Describe the characteristics that identify a sample of matter as being a substance. Classify each of the following as a physical or chemical property Iron and oxygen form rust Iron is more dense than aluminum Magnesium burns brightly when ignited Oil and water do not mix Mercury melts at -39 ℃ Using what you know about the compressibility of gases, explain why the oxygen in a SCUBA tank is compressed. Create a table that describes the three common states of matter in terms of their shape, volume, and compressibility.

Quick Think- Check The sample of matter must have a uniform and unchanging composition to be a substance. Properties Chemical (rust) Physical (density) Chemical (burning) Physical (mixing) Physical (melting) point) Particles of gas are spaced apart and are easily compressed. Therefore, it is possible to put a significant volume of oxygen in the tank, which allows the diver to remain under water longer! Solid Liquid Gas Definite volume Fills volume of container Definite shape Fills container shape Takes shape of container Incompressible Virtually incompressible Compressible

Changes in Matter I will define physical change and list several common physical changes I will define chemical change and list several indications that a chemical change has taken place I will apply the law of conservation of mass to chemical reactions

Physical CHANGES Alter a substance WITHOUT changing its composition Might result in dramatically different appearance (yet leave the composition of the substance unchanged) Examples Crunching up a piece of aluminum foil Cutting a sheet of paper Breaking a crystal Phase changes (solid, liquid, gas)

Key words of Physical Changes Bend Grind Crumple Split Crush

Chemical CHANGES A process that involves one or more substances changing into a NEW substance New substance Formed in reaction Different compositions — than original substance(s) Different properties — than original substance(s) Example Fermentation of juice, sugars, and other ingredients (making wine) Rusting of iron (a chemical combo of iron and oxygen)

Chemical CHANGES Commonly referred to as a chemical reaction Example Reactants Starting substances Products New substances Example Reactants = Iron, Oxygen Product = rust

Key Words of Chemical Changes Explode Rust Oxidize Corrode Tarnish Ferment Burn Rot

The LAW of Conservation of Mass Mass is neither created nor destroyed during a chemical reaction Mass is conserved Mass of Reactants = Mass of Products

Conservation of Mass Problem Known Mass mercury (II) oxide = 10.0g Mass liquid mercury = 9.26g Unknown Mass formed oxygen = ? g Mass Reactants = Mass Products Mercury (II) oxide = Mercury + Oxygen 10.0g = 9.26g + ? 0.740 g of Oxygen formed

Quick Think Describe the results of a physical change and 3 examples. Repeat with chemical change. A friend tells you, “because composition does not change during a physical change, the appearance of a substance does not change.” Is your friend correct? Explain WHY? Solve each of the following In the complete reaction of 22.99 g of sodium with 35.35 g chlorine, what is the mass of the sodium chloride formed? A 12.2 g sample of X reacts with a sample of Y to form 78.9 g XY. What way the mass of Y that reacted?

Quick Think-Check During a physical change a substance is altered but its composition does not change. EX melting, freezing, boiling, bending, tearing During a chemical change the composition of a substance IS altered. EX color change, odor, temperatures change, formation of gas or solid from a liquid. The statement is false. Composition doesn’t change but a change in appearance often accompanies a physical change. 58.44g of sodium chloride 66.7 g of Y

Mixtures of Matter I will contrast mixtures and substances I will classify mixtures as homogeneous or heterogeneous I will list and describe several techniques used to separate mixtures

Mixtures A combination of two or more pure substances Each pure substance retains its INDIVIDUAL chemical properties Most everyday matter occurs as mixtures Substances naturally tend to mix It is very difficult to keep things pure

Mixture Examples Water and Sand Water Sand Colorless liquid Sand Grainy solid Doesn’t dissolve in water Easily seen as two substances mixed Water and Table Salt Water Colorless liquid Table Salt White crystal solid Dissolves in water NOT easy to see both substances individually But if you boiled the water a white residue remains (salt!)

Types of Mixtures Heterogeneous Homogeneous Referred to as SOLUTIONS Doesn’t blend smoothly throughout Individual substances remain distinct Examples Water mixed with sand Fresh orange juice Pulp + Juice Pizza Dough + sauce + cheese + toppings Homogeneous Constant composition throughout Always has a single phase Examples Water mixed with salt Cough syrup lemonade Referred to as SOLUTIONS

Solutions Gas-Gas Gas-Liquid Liquid-Gas Liquid-Liquid Solid-Liquid EX. Air is primarily a mixture of nitrogen, oxygen, and argon gases Gas-Liquid EX. Carbonated beverages contain carbon dioxide gas in solution Liquid-Gas Ex. Moist air contains water droplets in air (which is a mixture of gases) Liquid-Liquid Ex. Vinegar contains acetic acid in water Solid-Liquid Ex. Sweetened powder drink contains sugar and other solid ingredients in water Solid-Solid Ex. Steel is an alloy of iron containing carbon

Separating Mixtures Filtration Ex through filter paper A technique that uses a porous barrier to separate a solid from a liquid Ex through filter paper Like coffee! Used to filter heterogeneous mixtures composed of solids and liquids Distillation A separation technique that is based on differences in boiling points A mixture is heated until the substance with the lowest boiling point boils to a vapor that can be condensed into a liquid and collected Used to filter homogeneous mixtures

Separating Mixtures Crystallization Chromatography Technique results in the formation of pure particles of a substance From a solution containing dissolved particles Ex rock candy From a sugar solution Often have to add just a little more than what the solution can possibly hold to get the crystals to come out of solution Produces HIGHLY PURE solids Chromatography Technique that separates the components of a mixture (mobile phase) on the basis of the tendency of each to travel or be drawn across another surface (stationary stage) EX. Soaking up a liquid with paper towel

Quick Think How do Mixtures and Substances differ? Classify each of the following as either heterogeneous or homogeneous mixtures Orange juice (with pulp) Tap water Steel (blend of iron/carbon) Air Raisin muffin Applying Concepts Describe the separation technique that could be used to separate each of the following mixtures Two colorless liquids A non dissolving solid mixed with a liquid Red and blue marbles of the same size and mass

Quick Think-Check Two colorless liquids (distillation) A non dissolving solid mixed with a liquid (filtration) Red and blue marbles of the same size and mass (by hand!) Substance = Matter that has a uniform and unchanging composition Mixture = A combination of two or more pure substances. Each pure substance retains its INDIVIDUAL chemical properties. Orange juice (heterogeneous) Tap water (homogeneous) Steel (blend of iron/carbon) (homogeneous) Air (homogeneous) Raisin muffin (heterogeneous)

Elements and Compounds I will distinguish between elements and compounds I will describe the organization of elements on the periodic table I will explain how all compounds obey the laws of definite and multiple proportions

Element A pure substance that cannot be separated into simpler substances by physical or chemical means Each element has its own unique chemical name and symbol Earth has 91 naturally occurring elements EX Copper Oxygen gold

Periodic Table 1869 Russian Chemist Dmitri Mendeleev First version –based on masses Blank spots for undiscovered elements Organizes the elements into periods (rows) and groups or families (columns) Elements in the same group have similar chemical and physical properties

Compounds A combination of two or more different elements that are combined chemically Most substances are compounds Ex Water Salt Sugar Aspirin Approximately 10 million known compounds About 100 000 new ones developed/discovered per year

Dirt, blood, milk Lemonade, gasoline, steel Salt, baking soda, sugar Oxygen, gold, iron

Compounds Can be broken down into simpler substances by chemical means Often requires external energy to separate Ex heat or electricity Ex separate water into hydrogen and oxygen using electrolysis More stable than the elements that make them up (in general)

Compounds Have DIFFERENT properties than those of the elements that make it up Ex water = clear liquid, hydrogen/oxygen clear gases Ex sodium chloride = white, unreactive solid that flavors many foods you eat, sodium = highly reactive element that fizzes and burns when added to water, chlorine = poisonous pale green gas VIDEO CLIP-ELEMENTS VS COMPOUNDS

Law of DEFINITE Proportions Regardless of the amount, a compound is ALWAYS composed of the same elements in the same proportion by mass bag sugar = 42.2% carbon, 6.50% hydrogen, 51.30% oxygen sugar cane = 42.2% carbon, 6.50% hydrogen, 51.30% oxygen SAME COMPOUND (SUCROSE) ! Conversely, compounds with DIFFERENT mass proportions MUST be DIFFFERENT compounds

Percent by Mass (%) 𝒎𝒂𝒔𝒔 𝒐𝒇 𝒆𝒍𝒆𝒎𝒆𝒏𝒕 (𝒑𝒂𝒓𝒕) 𝒎𝒂𝒔𝒔 𝒐𝒇 𝒄𝒐𝒎𝒑𝒐𝒖𝒏𝒅 (𝒘𝒉𝒐𝒍𝒆) X 100 = percent by mass (%) % by mass demonstration Practice Problems A 78.0 g sample of an unknown compound contains 12.4 g of hydrogen. What is the Percent by mass of hydrogen in the compound? Two unknown compounds are tested. Compound A contains 15.0 g of hydrogen and 120.0 g of oxygen. Compound B contains 2.0 g of hydrogen and 32.0 g of oxygen. Are the compounds the same? All you know about 2 unknown compounds is that they have the same percent by mass of carbon. Is that enough information to be sure the two compounds are the same?

Law of MULTIPLE Proportions Can compounds that are composed of the same elements differ from each other? YES, different compounds have different mass compositions When different compounds are formed by a combo of the same elements, different masses of one element with the same relative mass of the other element in a ratio of small whole numbers Ratios compare the relative amounts of any items or substances