Understanding Science Lab Reports, Properties of Matter, and Chemical Reactions

1. 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.) 0.00076 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

2. Answers to Warm-Up (9/26) (1.) Introduction, Materials, Procedures, Data Table, Conclusion (2.) a.) 7.6 x 10-4 g b.) 3.459 x 108 L c.) 8.21 x 101 m (3.) a.) 2.3 x 103 cm b.) 9.48 x 10-2dL c.) 7.6 x 1018 pg

3. Chapter 2Matter and Change Ms. Riggins Lawndale High School

4. Chapter 2.1 – Properties of Matter • Properties used to describe matter can be classified as extensive or intensive

5. 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)

6. Practice • Classify the following properties as extensive or intensive • 5 pounds of apples • Glass Jar • 2 miles long • Plastic Box • Odor

7. Identifying Substances Every sample of the same substance has identical intensive properties because every sample has the same composition • Physical Property – a quality of a substance that can be observed or measured (color, hardness, shape, state of matter, boiling temperature)

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

9. States of Matter • Liquid – form of matter that has an indefinite shape with a definite volume (usually flows)

10. States of Matter • Gas – form of matter that has an indefinite shape and volume (takes the shape and volume of its container

13. Physical Changes • Physical Change – when properties of a material change, but the composition does not change • Examples – break, split, cut, crush, boil freeze, melt, condense • Physical changes can be reversible (melting) or irreversible (cutting hair, filing nails, cracking an egg)

14. Chemical Change • Chemical Change – a change that produces matter with a different composition than the original matter • Example – heating can be used to break down some compounds into new compounds, or electricity can break down water into hydrogen and oxygen

15. Chapter 2.2 - Mixtures • A physical blend of two or more components

16. 2 Types of Mixtures (1.) Homogeneous – a mixture in which the composition looks the same throughout (also known as solution) For example: oil or vinegar separately (2.) Heterogeneous – a mixture in which the composition does NOT look the same throughout (chicken soup, salad, oil & vinegar mixed together)

17. Separating Mixtures 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 grounds to make coffee) • Distillation – a process involving liquid being boiled to produce a vapor, which is then condensed back to a liquid

18. Chapter 2.3 - Elements and Compounds • Element – simplest form of matter (oxygen, carbon, nitrogen) Compound – substance that contains two or more elements chemically combined together

19. Elements vs. Compounds • Compounds can be broken down into simpler substances, but elements cannot • Compound = H2O • Elements = 2 hydrogen’s 1 oxygen

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

21. Practice • Classify the following materials as element, compound, or mixture • Table Salt (NaCl) • Salt Water • Sodium (Na)

22. Chemical Symbols • 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 1st letter is always CAPITALIZED, while the 2nd letter (if used) is lowercase. (Example: H, O, C, Cl, He, Na)

23. Chemical Formulas • Anytime subscripts are used in a formula, they indicate the number of elements in the compound • How many atoms does each formula contain? • NaOH • BaCr2O7 • C12H22O11 • HC2H3O2 • Mg(OH)2

24. Chapter 2.4 – Chemical Reaction • During a physical change, physical properties change. During a chemical change, chemical properties change. • The result of a chemical reaction can produce a physical or chemical change, or both

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

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

27. Chemical Reaction One or more substances changes into one or more new substances

28. 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

29. How to Recognize a Chemical Change (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)

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

31. 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