Chapter: 3 (9-13-18_Notes) 3.2 Changes in matter MAIN IDEA: Matter can undergo chemical and physical changes.

Heterogeneous Mixtures Chapter - 3 Concept Map: Examples: Compounds Elements Chemical changes Mixtures Pure Substances Physical changes Matter Homogeneous Mixtures Heterogeneous Mixtures

3 physical changes: Solid Liquid Gaseous How many changes of the substance, H2O is shown in this photo? 3 physical changes: Solid Liquid Gaseous

Changes in matter Physical change: Chemical change: A change in which matter may look or behave differently but no new substance is formed A change in which new substances are formed

Organize the following as physical or chemical change Lighting up a match Color change on leaves condensation Sugar crystal formation Cooking eggs Bubbling soda drink Rusting of iron Chopping a carrot

Organize the following as physical or chemical change Physical change: Chemical change: Color change on leaves Cooking eggs Sugar crystal formation Bubbling soda drink condensation Lighting up a match Chopping a carrot Rusting of iron

Changes in matter Physical change: Chemical change: A change in which matter may look or behave differently but no new substance is formed A change in which new substances are formed Ex: chopping/cutting distillation Freezing Evaporation Crystallization Melting Vaporization Ex: Cooking Combustion (burning) Rust formation

Evidence of chemical reactions Example Color change Rust formation on iron (reddish) Change in temperature Baking soda mixed with water Precipitate (solid) formation Curdling of milk results in clumping Production of new gas Photosynthesis reaction results in oxygen synthesis Change in smell Rotting food

Law of Mass Conservation Mass reactants = Mass products When a chemical reactions takes place inside a closed system, matter is neither created or destroyed. OR, When a chemical reactions takes place inside a closed system, mass of reactants equals the mass of the products. Mass reactants = Mass products

How to write chemical equations for reactions Each element (type of atom) has a chemical symbol. So, each substance has a chemical formula that tells you’re the number of each type of element (atom) it contains. Subscripts indicate number of atoms of each element in each substance A number in front of the substance indicates the moles (parts) of the substance that is present in the reaction. (Every element is multiplied by this number) A plus sign is used to show multiple reactants or products An arrow indicated the direction of the reaction (points to products) EXAMPLE: Magnesium Magnesium oxide Oxygen gas + Mg MgO O2 + Unbalanced 2 Mg 2 MgO O2 + Balanced 2( XY) = 2X and 2Y 2.Mg and 2.Oxygen

LAB6: Mass measurement Instructions New gas in side balloon Products Deflated balloon Baking soda Vinegar Reactants = vinegar + Baking soda Products = gas + new liquid Flask and balloon only AFTER Reaction= products BEFORE Combining reactants = reactants Mass = M3 Mass = M1 Mass = M2 Mass of Reactants only = M2 – M1 Mass of products only = M3 – M1

Matter - Properties & Changes Chapter - 3 Matter - Properties & Changes 3.1 Properties of matter ( Text Book p70-75) MAIN IDEA: Most common substances have diverse chemical and physical properties and exist as solids liquids or gases. 3.2 Changes in matter (Text Book p76-79) MAIN IDEA: Matter can undergo chemical and physical changes 3.3 Mixtures of matter (Text Book p80-83) MAIN IDEA: Most everyday matter occurs as mixtures – combinations of two or more substances. 3.4 Elements & compounds (Text Book p84-91) MAIN IDEA : A compound is a combination of two or more substances