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Matter & Its Properties. Modern Chemistry Textbook: Ch. 1. Basic Building Blocks of Matter. What is matter?. Anything that takes up space and has mass Takes up space volume Certain amount of stuff mass How does one make stuff? Start with the ATOM!. What is chemistry?.
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Matter & Its Properties Modern Chemistry Textbook: Ch. 1
What is matter? • Anything that takes up space and has mass • Takes up space volume • Certain amount of stuff mass • How does one make stuff? • Start with the ATOM!
What is chemistry? • The study of matter and the changes it undergoes • Composition • Structure • Properties • Energy changes
Elements vs. Compounds • Atom – smallest unit of an element that has the chemical identify of that element • Element – Pure substance that cannot be broken down into simpler, stable substances • So only 1 kind of atom (a few or many) • Compound – Pure substance that can be broken into simpler, stable substances • must have 2 different kinds of atoms
States of Matter States of Matter Elements & Compounds can be found in many different states of matter or phases What’s the Difference between States of Matter Video Substances only move from one phase to another by physical means.
What physical characteristics can you observe to determine a substances state of matter? Indefinite volume Indefinite shape Definite volume Definite shape Definite volume Indefinite shape Shape volume
Plasma: high-temperature state of matter in which atoms lose most of their electrons
Physical vs. Chemical Properties Physical property – characteristic of a substance that can be observed/measured without altering substances identify Physical change – change in which identify of substance is not altered
Physical changes will always require the absorption/release of energy • (Heat or light)
What if a substance’s identity is altered? Chemical Property – ability to undergo changes that transforms substance into a new substance Chemical change – change in which 1 or more substances are converted into different substances
Chemical Changes yields Reactants substances that react Products substances that are formed
Evidences of Chemical Change Evolution of energy (heat/light) Color change Formation of a gas Formation of precipitate
Energy is always involved in physical and in chemical changes Law of Conservation of Energy: energy can be absorbed or released, but is never destroyed or created.
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C C C P C P _______ 1 . Hydrochloric acid reacts with potassium hydroxide to produce a salt, water and heat. _______ 2. A pellet of sodium is sliced in two. _______ 3. Water is heated and changed to steam. _______ 4. Iron rusts. _______ 5. Evaporation _______ 6. Milk sours. _______ 7. Ice melting. _______ 8. Wood rotting. _______ 9. When placed in H2O, a sodium pellet catches on fire as H2 gas is liberated and sodium hydroxide forms. _______ 10. Grass growing in a lawn. _______ 11. A tire is inflated with air. _______ 12. Food is digested in the stomach. _______ 13. Water is absorbed by a paper towel. _______ 14. Sugar dissolved in water. P C C P C P P P
Classification of Matter Grouping matter to make identification easier
Mixtures Blend of 2 or more kinds of matter, each that retain its own identify and properties • Mixed together physically • Can be separated physically (no chemical rxn’s needed) • Homogeneous (solutions): uniform in composition • Salt – water solution • Heterogeneous: not uniform throughout • Clay-water mixture
Homogenous mixture Heterogeneous mixture
Heterogeneous Mixtures • Suspensions – particles in solvent so large that they settle out unless constantly stirred/agitated • Colloids – particles of intermediate size that stay dispersed throughout a mixture. • Often appears cloudy • Use Tyndall Effect to identify (shine light source through mixture and particles become visible in beam of light)
Pure Substances Fixed composition • Every sample of pure substance has exactly the same properties and composition • Ex: Water isalways 11.2% hydrogen and 88.8% oxygen by mass (determined from periodic table)
Element Pure Compound Pure Mixture Heterogeneous Mixture Homogeneous Pure Element Pure Compound Mixture Heterogeneous Mixture Homogeneous Mixture Homogeneous Pure Element
Introduction to the Periodic Table Section 1.3
What is the periodic table? Why don’t elements and their symbols always look like they correspond to each other?
Groups Periods
Groups & Families • The vertical columns of the periodic table are called groups, or families. • Each group contains elements with similar chemical properties. • The horizontal rows of elements in the periodic table are called periods. • Physical and chemical properties change somewhat regularly across a period.
Metals elements to the left of the zigzag line Properties of metals • Mostsolidsat room temperature • Malleable (hammered or rolled into thin sheets) • Ductile (drawn into a thin wire) • conduct electricity and heat well
Metals Gold, copper, aluminum
Nonmetals right of the zigzag line an element that is a poor conductor of heat and electricity Properties of nonmetals • many are gases • solids are brittle • poor conductorsof heat and electricity
Nonmetals (a) carbon, (b) sulfur, (c) phosphorus (d) iodine
Metalloids surrounds zigzag line an element that has some characteristics of metals and some characteristics of nonmetals Properties of metalloids • all metalloids are solidsat room temperature • semiconductorsof electricity • **Aluminum is not a metalloid – it’s a metal!
Noble Gases Elements in Group 18 Properties of Noble Gases • Generally unreactive (i.e. “inert”) • Gases at room temperature • Glow if electricity is passed through them