1. Matter, Energy and Change Chemistry and Measurement Sections 1.3 – 1.4

2. Chemistry  Chemistry is the study of matter and the changes it undergoes.  What is matter?  How is matter classified?  What physical and chemical properties does matter possess?

3. Solid

6. States of Matter (Phases)

7. Physical Properties  Physical Properties: Characteristics that can be observed without changing the chemical composition of the substance Characteristics that can be observed without changing the chemical composition of the substance

8. Physical Properties Examples of physical properties: Examples of physical properties: States of matter (Phases)  s = solid;States of matter (Phases)  s = solid; l = liquid; g = gas l = liquid; g = gas ColorColor SizeSize OdorOdor Mass (grams = g)Mass (grams = g) Density (mass/volume)Density (mass/volume) Volume Texture Solubility (maximum amount of solute that can be dissolved in a solvent) Viscosity Boiling point (bp) Freezing point (fp) Melting point (mp)

9. Chemical Properties  Description of what happens when two substances react with one another  For example: Was heat, light, sound, or some other form of energy generated? Did a reaction take place at all (if not, the materials are non- reactive - which is a chemical property)? Were gases formed? Was it endothermic or exothermic?

10. Endothermic & Exothermic Reactions  Endothermic reaction: chemical reactions which absorb heat in order to proceed Barium hydroxide reacts with ammonium nitrate Barium hydroxide reacts with ammonium nitrate Demo: http://www.youtube.com/watch?v=GmiZ0huvZ zs Demo: http://www.youtube.com/watch?v=GmiZ0huvZ zs http://www.youtube.com/watch?v=GmiZ0huvZ zs http://www.youtube.com/watch?v=GmiZ0huvZ zs

11. Endothermic & Exothermic Reactions  Exothermic reaction: chemical reactions that release energy in the form of heat, light or sound; produce heat and may be explosive Potassium permanganate Potassium permanganate Demo: http://www.youtube.com/watch?v=80Q3GgeeI VM&feature=related Demo: http://www.youtube.com/watch?v=80Q3GgeeI VM&feature=related http://www.youtube.com/watch?v=80Q3GgeeI VM&feature=related http://www.youtube.com/watch?v=80Q3GgeeI VM&feature=related

12. Physical and Chemical Changes  Physical change: change that does not alter the chemical composition of a substance E.g. change in state, dissolves in water (aqueous) E.g. change in state, dissolves in water (aqueous)

13. Physical Changes

14. Physical and Chemical Changes  Chemical change: change that results in a new substance with new properties and chemical composition; materials combine chemically with another material, and cannot be separated by any physical means. E.g. color change, formation of a precipitate, evolution of a gas, burning, oxidation (rusting) E.g. color change, formation of a precipitate, evolution of a gas, burning, oxidation (rusting)

15. Chemical Changes http://www.youtube.com/watch?v=opY3FLrPTa4

16. Conservation of Mass, Energy  Law of Conservation of Mass Total mass remains constant during a chemical reaction Total mass remains constant during a chemical reaction  Law of Conservation of Mass is why we must balance equations (# of atoms in reactants must equal # of atoms in products)  Changes of mass (i.e. loss of heat) in chemical reactions are too small to detect

17. Mixtures and Pure Substances  MIXTURES - A mixture can be physically separated into pure compounds or elements.  MIXTURES - A mixture can be physically separated into pure compounds or elements. Just about everything that you can think of is probably a mixture. Just about everything that you can think of is probably a mixture. Examples: concrete, salt water Examples: concrete, salt water

18. Mixtures and Pure Substances  PURE COMPOUNDS - A pure compound has a constant composition with fixed ratios of elements. Example: distilled water contains water molecules and only water molecules Example: distilled water contains water molecules and only water molecules

19. Mixtures & Pure Substances  Law of Definite Proportions: states that chemical compounds always contain the same ratio of elements by mass Water is always 1 g of hydrogen to 8 g of oxygen Water is always 1 g of hydrogen to 8 g of oxygen  Law of Multiple Proportions: when elements combine, they do so in a ratio of small whole numbers Carbon and oxygen react to form CO or CO 2, not CO 1.8 Carbon and oxygen react to form CO or CO 2, not CO 1.8