QOD Discuss how you would apply the scientific method to the hypothesis that cigarette smoking is dangerous. Question: Hypothesis: Cigarette smoking is dangerous Experimental Plan:

Question of the Day Your task is to develop a device that will measure the trustworthiness of someone’s character. Would you be more concerned about the precision of the device or the accuracy? Why? What types of attributes (qualities) would it measure?

Classification of Matter Dr. Z

Matter Matter is anything that has mass or takes up space

Physical States Solid, Liquid, and Gas

Solid Solid matter has definite shape and volume Solids can be two types

1. Crystalline Solids Crystalline is a type of solid that has a regular arrangement or pattern to its atoms

2. Amorphous Solids Amorphous solids have no particular arrangement of their atoms. Examples: plastics and gels

Crystalline v. Amorphous

LIQUIDS Liquid: Definite volume but not definite shape

A gas has neither definite volume nor shape Gases A gas has neither definite volume nor shape

Matching Terms Definitions 1. ____ Matter 2. ____ Solid 3. ____ Crystalline 4. ____ Liquid 5. ____ Gas A. no definite volume or shape B. Definite volume AND shape C. repeating pattern of atoms D. Definite volume but not definite shape E. Anything that takes up space or has mass

Matching Terms Definitions 1. __E_ Matter 2. __B_ Solid 3. __C_ Crystalline 4. __D_ Liquid 5. __A__Gas A. no definite volume or shape B. Definite volume AND shape C. repeating pattern of atoms D. Definite volume but not definite shape E. Anything that takes up space or has mass

Substances Substance: kind of matter with definite, fixed composition.

Analysis Classifying Matter

Matter Pure Substance Mixture elements (periodic table) compounds (elements bonded together) Homogeneous Solutions Heterogeneous Suspensions Colloids

Compound (bonded elements) Matter Pure Substance Element (Per. Table) Compound (bonded elements) Mixture Homogeneous Solution Heterogeneous Colloid Suspension

Matter Pure Substances Elements Compounds

                                                                          Back to Main Page Elements Fundamental substances that cannot be broken down by chemical means to a simpler substance Ex. Any element can be found on the periodic table.

Compounds Compounds are elements that have been bonded together (by their electrons) Examples: pure water, salt, & sugar

The types of mixtures can be distinguished by the number of phases If it is not a pure substance (element or compound), then it is a mixture. The types of mixtures can be distinguished by the number of phases

Phases Phase = part of a system separated by physical boundaries from the other parts

How many different phases do you see?

Matter Mixtures Heterogeneous Homogeneous

Mixtures If a substance is NOT a pure substance than it is a mixture Mixtures can be two types Homogeneous: one phase, uniform Heterogeneous: two or more phases

Homogeneous or Heterogeneous?

Matching Pictures 1. Terms 2. A. element B. compound 3. 4. Terms A. element B. compound C. Homogeneous mixture D. Heterogeneous mixture

Matching A. element B. compound C. Homogeneous mixture D. Heterogeneous mixture

So… How do you know?

Now begin HW Read the worksheet on Describing Matter Answer questions on the back Read the worksheet on Elements from Stardust

Elements and Names Atoms are the smallest particle of an element that can exist Symbols are the one or two letter abbreviations for the elements. The first letter is always capitalized and the second (if there is one) is NEVER capitalized.

Metals, Metalloids and Nonmetals Metals: high luster, high melting point, good conductors of electricity, ductile (can be drawn into wire), malleable (can be smashed into thin sheets) Nonmetals: no luster, low melting points, poor conductors, neither ductile or malleable Metalloids: intermediate properties

Group Numbers

Formulas Chemical Formulas show the symbols and ratios of the atoms of an element in a compound Ex. H2O (2 hydrogen and 1 oxygen) Ca(NO3)2 (1 calcium, 2 nitrogen and 6 oxygen) 4(NH4)2SO4 (8 N, 32 H, 4 S, and 16 O)

Now complete the homework Read pp. 120-128 P. 128 Q#8

A ratio of measurements Density A ratio of measurements

Density Density is a ratio of the mass to volume Density = mass (usually in g) / volume (usually in mL or cm3) 1mL = 1 cm3

Which would have a larger density? Gold coin Styrofoam peanut

Formula for Density D = m/v Solve for V in terms of m and D V = m/D Solve for m in terms of v and D m = (V) (D)

Example Find the density of a substance which has a mass of 9.01 g and a volume of 5.38 mL D = m/v D = 9.01 g/ 5.38 mL 1.67472119 (round for sig figs) 1.67 g/mL

Example The mass of a sample is 6.835 g and a density of 13.67 cm3. Find the volume. D = m/v V= m/d V = 6.835g/ 13.67 g/cm3 V = 0.5 (round for sig figs) V= 0.5000 cm3

Now begin making flashcards of the 30 elements and symbols Ex. Side 1 H Ex. Side 2 hydrogen

Define these terms. Pages 120 – 128 are an excellent resource to find this information. Alkaline earth metal Transition metal Halogen Nobel gas Metal Nonmetal Semiconductor Alkaline metal

Diatomic Elements Some elements always occur as diatomic molecules when they are in their elemental state (not bonded to any other element) Ex. H by itself is H2 as is F2, N2, O2, Cl2, Br2, I2 But other elements like Na or Fe are not diatomic