Warm-Up (9/26) (1.) List and describe in detail the 5 components that make up a good science lab report. (2.) Write the following in scientific notation: a.) g b.) 345,900,000 L c.) 82.1 m (3.) Convert the following measurements: a.) 23 m  cm b.) 9.48 mL  dL c.) 7.6 Mg  pg

Answers to Warm-Up (9/26) (1.) Introduction, Materials, Procedures, Data Table, Conclusion (2.) a.) 7.6 x g b.) x 10 8 L c.) 8.21 x 10 1 m (3.) a.) 2.3 x 10 3 cm b.) 9.48 x dL c.) 7.6 x pg

Chapter 2 Matter and Change Ms. Wang Lawndale High School

Describing Matter Properties used to describe matter can be classified as extensive or intensive

Extensive and Intensive Extensive – depends on the amount of matter in a sample (mass or volume) Intensive – depends on the type of matter in a sample (hardness/softness)

Identifying Substances Physical Property – a quality or condition of a substance that can be observed or measured without changing the substance’s composition Look at the 3 objects I have on the front demo table… Every sample of a given substance has identical intensive properties because every sample has the same composition.

States of Matter Solid – form of matter that has a definite shape and volume

States of Matter Liquid – form of matter that has an indefinite shape, flow, yet has a fixed volume

States of Matter Gas – form of matter that takes both the shape and volume of its container

Mixtures (Observe the oil and vinegar) A physical blend of two or more components

Types of Mixtures (1.) Homogeneous – a mixture in which the composition IS uniform throughout (oil, vinegar) (2.) Heterogeneous – a mixture in which the composition IS NOT uniform throughout (chicken soup, salad, oil & vinegar)

Separating Mixtures (Observe the heterogeneous mixture of Styrofoam, pennies, and water) You can use a variety of methods to separate mixtures depending on the substances and their physical properties. Filtration – process that separates a solid from a liquid in a heterogeneous mixture (cooked pasta in a colander, coffee) Distillation – a process involving liquid being boiled to produce a vapor, which is then condensed back to a liquid

Substances vs. Mixtures Substance – composition of a material is fixed (Elements and Compounds) Mixture – composition of a material varies (Homogeneous and Heterogeneous Mixtures)

Elements and Compounds Element – simplest form of matter that has a unique set of properties Compound – substance that contains two or more elements chemically combined in a fixed proportion

Symbols and Formulas Chemists use chemical symbols to represent elements, and chemical formulas to represent compounds Each element is represented by a 1- or 2-letter chemical symbol The 1 st letter is always CAPITALIZED, while the 2 nd letter (if used) is lowercase. (Example: H, O, C, Cl, He, Na)

Physical Changes During a physical change, properties of a material change, but the composition of the material does not. Physical Changes include… BOILING MELTING FREEZING CONDENSING BREAKING CUTTING CRUSHING

Chemical Change A change that produces matter with a different composition than the original matter

Reactant versus Product Reactants - Substance present at the beginning of the reaction (left side) Products - Substance present at the end of the reaction (right side) Reactant  Product 

(1.) Transfer of energy (heat) (2.) Change in color (3.) Produces a gas (bubbles) (4.) Forms a precipitate (solid that forms and settles out of a liquid mixture) Recognizing Chemical Changes…

Conservation of Mass During any chemical reaction, the mass of the products is always equal to the mass of the reactants Example: 10 grams of ice melts into 10 grams of water Law of Conservation of Mass – mass is conserved in any physical change or chemical reaction (mass is neither created nor destroyed)

Classwork Sec 2-1 #’s 5, 8 Sec 2-2 #’s 11, 14, 16, 17 Sec 2-3 #’s 20, 21, 24, 25, 26, 27 Sec 2-4 #”s 29, 30, 31, 32, 33, 34