Chapter 3 3.1 – Properties of Matter

Substances Matter – has mass & takes up space Substance – matter with uniform and definite composition Ex: Salt, pure water, air, etc.

States of Matter All matter can be classified as one of 3 physical forms: Solid – definite shape and volume -Particles tightly packed & do not conform to container.

States of Matter Liquid – Matter that flows, constant volume, & takes shape of container -Particles are NOT rigidly held in place and are less closely packed than those of a solid.

States of Matter Gas – flows to conform to container & fills entire volume -Large amounts of space between particles & a gas will compress easily.

States of Matter

States of Matter **NOTE** Vapor is NOT the same as gas! ~ Vapor is a solid or liquid at room temp (a gas is still a gas at room temp!) ex: Steam is a vapor

Physical Properties of Matter Physical Property – characteristic that is observable or measured w/o changing composition. Ex: Denisty, color, melting point, boiling point, smell, etc.

Physical Properties of Matter – cont. Physical properties can be broken down into further into two types: Extensive Properties – dependent on amount of substance present (mass, length, etc.) Intensive Properties – amount of substance is not important (density, color, etc.)

Chemical Properties Chemical Property – ability of substance to combine w/ or change into one or more other substances Ex: Rust

Observing Properties of Matter Do surrounding conditions affect properties? How or why not? When making observations, be sure to state specific conditions such as temperature, pressure, etc. for more repeatable results!

Chapter 3 3.2 – Changes in Matter

ex: water cycle – (freeze, boil, condense, vaporize, etc) Physical Changes Physical Change – change that alters substance w/o changing composition ex: wadding up paper Phase Change – transition of matter from one state to another physical since depends on temp & pressure of surroundings ex: water cycle – (freeze, boil, condense, vaporize, etc)

Chemical Change Chemical Change – one or more substances changing into new substance The new substance will have different composition and properties! Reactants – starting substance Products – new substance formed **Decompose, rust, explode, oxidize, corrode, tarnish, burn, rot, etc = chemical rxn.

𝑚𝑎𝑠𝑠 𝑟𝑒𝑎𝑐𝑡𝑎𝑛𝑡𝑠 = 𝑚𝑎𝑠𝑠 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑠 Conservation of Mass Mass is neither created nor destroyed during a chemical rxn ~ it’s conserved! 𝑳𝒂𝒘 𝒐𝒇 𝑪𝒐𝒏𝒔𝒆𝒓𝒗𝒂𝒕𝒊𝒐𝒏 𝒐𝒇 𝑴𝒂𝒔𝒔: 𝑚𝑎𝑠𝑠 𝑟𝑒𝑎𝑐𝑡𝑎𝑛𝑡𝑠 = 𝑚𝑎𝑠𝑠 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑠

Example 1 In catalytic converter found in car exhaust, carbon monoxide (CO) reacts with oxygen gas ( 𝑂 2 ) to form carbon dioxide ( 𝐶𝑂 2 ). If CO reacts with 16g of 𝑂 2 to form 44g of 𝐶𝑂 2 , what is the mass of CO in the catalytic converter? 𝑚 𝐶𝑂 + 𝑚 𝑂 2 = 𝑚 𝐶𝑂 2 16𝑔+𝑥=44𝑔 28g CO

Chapter 3 3.3 – Mixtures of Matter

Mixtures Pure Substance – uniform and definite composition Mixture – Combo of 2 or more pure substances Each pure substance retains individual chem properties **Most everyday matter occurs as mixtures since pure substances tend to mix naturally (difficult to keep pure!)

Types of Mixtures Heterogeneous Mixtures – does not blend smoothly throughout (composition is NOT uniform) Ex: Italian Salad Dressing Homogeneous Mixture – Constant composition throughout Ex: Tea AKA – solutions (can occur as solid, liquid and/or gas)

Tyndall Effect Tyndall Effect – Quick test to differentiate solution from heterogeneous mixture Shine thin beam (laser) of light through beaker (glass container) If light does not shine through => solution If light shines though - heterogeneous

Separating Mixtures Since most substances are physically combined, most can be physically separated! **Take advantage of the physical properties to separate if possible!

Techniques for Separating Mixtures Filtration- easy on heterogeneous solid/liquid mixtures Use porous barrier to separate solids from liquids (coffee filters) Distillation – most homogeneous mixtures can be separated using distillation Based on ∆ in BP Mixture heated until substance w/ lowest BP boils to a vapor that can be condensed & collected as a liquid

Techniques for Separating Mixtures – Cont. Crystallization – results in the formation of pure solid particles of a substance from soln containing dissolved substance (collects as crystals) Ex: rock candy Sublimation – process of changing solid to vapor without melting/going through liquid phase Can be used to separate 2 solids in mixture when one solid will sublimate and not other

Techniques for Separating Mixtures – Cont. Chromatography – separates compounds of mixture based on ability of each component (gas or liquid) to travel/be drawn across surface of another material (chromatography paper) Components w/ strongest attraction to surface travel slower

3.4 – Elements and Compounds Chapter 3 3.4 – Elements and Compounds

Elements All matter can be broken down into small, basic building blocks Element – pure substance that can’t be separated into simpler substance by phys/chem means 92 elements occur naturally Each has unique chem name & symbol 1st letter ALWAYS capitalized and other letters are lowercase. Ex: Gold - Au, Silver – Ag, Oxygen – O, etc.

1st Periodic Table 1869 Russian Chemist (Mendeleev) created 1st version of periodic table Classification based upon similarities and masses of elements. Periodic Table – organizes elements into a grid of horizontal rows (periods) & vertical columns (groups/families)

Compounds Compound – made up of 2 or more different elements that are combined chemically ~10 million known compounds Increases at a rate of ~100,000/year Chemical symbols make it easy to write formulas for compounds (ex: NaCl, H2O)

Compounds – cont. Properties: Prop. of compound different than prop of individual elements.

Classification of Matter Mixtures Heterogeneous Homogeneous Pure Substance Elements Compounds

Law of Definite Proportions Elements that make up compounds always combine in definite proportions. Law of Definite Proportions – compound is always composed of same elements in same proportion by mass, regardless of sample size

Law of Definite Proportions – cont. Relative amts of elements in compound can be found by percent mass. % 𝑏𝑦 𝑀𝑎𝑠𝑠= 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑒𝑙𝑒𝑚𝑒𝑛𝑡 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑐𝑜𝑚𝑝𝑜𝑢𝑛𝑑 ×100

Example 2 A 78.0g sample of unknown compound contains 12.4g of hydrogen. What is % by mass of hydrogen? 12.4𝑔 𝐻 78.0𝑔 𝑐𝑜𝑚𝑝𝑜𝑢𝑛𝑑 ×100= 15.9%

Practice Do #72 & 75 on p. 95