Chapter 3: Matter: Properties and Change

Properties of Matter Physical Property: Can be observed or measured without changing the sample’s composition. Examples: density, color, taste, hardness, boiling point.

Properties of Matter Chemical Property: The ability of a substance to combine with or change into another substance Examples Does it burn in air? Does it react with water? Is it relatively inert? (Does it react with nothing?)

p. 60 # 2 – physical or chemical property? (a) Iron and oxygen form rust (b) Iron is more dense than aluminum (c) Magnesium burns brightly when ignited (d) Oil and water do not mix (e) Mercury melts at -39C Chemical Physical Chemical Physical

Indicators of a Chemical Reaction What are the signs that a chemical reaction has occurred? 1. A gas has been produced (bubbles) 2. A change in color 3. A change in temperature 4. A precipitate forms (new solid forms) 5. Light is produced 6. New odor 7. Explosion

What are the four states of matter? Solid Liquid Gas Plasma

Compressibility: Can you compress it? nono yes

SolidLiquidGas Melting Sublimation Freezing Evaporation Condensation Deposition

Law of Conservation of Mass In any physical change or chemical reaction, mass is conserved. Mass can be neither created or destroyed.

Conservation of Mass Law of Conservation of Mass – During any chemical reaction, the mass of the products is always equal to the mass of the reactants. Reactants  Products Mass reactants = Mass products

Conservation of Mass Practice – Mercury (II) oxide is heated and forms 200 g mercury metal and 16 g oxygen gas. How much reactant did you start with? 2 HgO  2Hg(s) + O2 ?? 200 g 16 g – Mass of HgO = 200 g + 16 g = 216 g

Conservation of Mass Practice – 10 g mercury (II) oxide is heated g mercury metal remains in flask. How much oxygen formed? 2 HgO  2Hg(s) + O g 9.26 g ?? 10 g = Mass of O 2 Mass of O 2 = g – 9.26 g = 0.74 g