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? 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 identity of that element Element – Pure substance that cannot be broken down into simpler, stable substances So only 1 kind of atom Examples; Na, H2, Cl2, Ca Compound – Pure substance that can be broken into simpler, stable substances must have 2 different kinds of atoms Examples; H2O, NaCl, CO2

Is this an element?

What’s the Difference between States of Matter Video 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. States of Matter

Physical vs. Chemical Properties Physical change – change in which identity of substance is not altered Examples: ripping, heating, freezing Physical property – characteristic of a substance that can be observed/measured without altering substances identity Examples: color, size, texture

Extensive Property: a property of a substance that changes when the amount changes; it is dependent on the AMOUNT of substance present Examples: volume, mass, energy… Intensive Property: a property of a substance that is always the same for that substance; it is NOT dependent on the AMOUNT of substance present Examples: density, boiling point, melting point, conductivity…

Physical changes will always require the absorption/release of energy (Heat or light)

What physical characteristics can you observe to determine a substance’s state of matter? Shape volume Indefinite volume Indefinite shape Definite volume Definite shape Definite volume Indefinite shape

Plasma: high-temperature state of matter in which atoms lose most of their electrons

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

substances that are formed 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.

Physical Chemical Extensive Intensive 1. Color 2. Combustibility 3. Hardness 4. Luster 5. Flammability 6. Reacts with acids to form H2 7. Mass 8. Density 9. Melting Pt. 10. Can neutralize a base 11. Ductility 12. Odor 13. Weight 14. Malleability 15. Tendency to corrode 16. Length ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

C C _______ 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. C P C P 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 identity 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

Heterogeneous 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 is always 11.2% hydrogen and 88.8% oxygen by mass (determined from periodic table)

Pure substance or mixture Column B Column A Pure substance or mixture Column B Element or Compound/Heterogeneous or Homogeneous 1. Chlorine 2. Water 3. Soil 4. Sugar water 5. Oxygen 6. Carbon dioxide 7. Rocky road ice cream 8. Alcohol 9. Pure air 10. Iron

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.

4 Basic Categories of Elements

elements to the left of the zigzag line Metals elements to the left of the zigzag line Properties of metals Most solids at 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 conductors of heat and electricity

(a) carbon, (b) sulfur, (c) phosphorus (d) iodine 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 solids at room temperature semiconductors of 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