Chemical Properties Physical Science

Questions, Questions, Questions… On a piece of paper, write down one question you have about or would like to have answered within the context of CHEMISTRY!!! When your done, crumple up the paper into a ball and hold onto it until you get further instructions!

Back to the Basics Matter – anything that has mass and volume Substance – type of matter with a constant composition and can be identified by a chemical symbol or chemical formula and distinct properties. Water, Salt, Aluminum Element – any substance made up of only one type of atom Oxygen, Helium, Iron Compound – a substance in which two or more elements are combined Chlorine Gas + Sodium metal = Sodium Chloride (salt) Cl2 + Na = NaCl

Element vs. Compound

The Chemistry Behind the Science Fair Project Volcano What do you notice happening when you mix baking soda and vinegar together??

Chemical Properties Describes a specific chemical change that alters the composition of a substance Reactivity Flammability Light Exposure

Chemical Changes Any change that results in the formation of new substances Examples: Combustion – combines with oxygen and burns Corrosion – weakening/discoloration of metals Oxidation – substances combine with oxygen In all examples… the key is that there is a formation of a new material!

Indications of Chemical Change Gas Formation (Bubbles/Vapors) Temperature Change Endothermic – Energy is absorbed; temperature decreases Exothermic – Energy is released; temperature increases Formation of a precipitate Precipitate – solid that forms when two liquids are mixed Light Energy Color Change

Something to think about… Ever bite into an apple… then leave it on the counter and come back to it later and it looks like this?? Why do you think this happened?

Elephant Toothpaste… She said what????? Reaction 2 H2O2(aq) --> 2 H2O(l) + O2(g) Let’s take a look!! Is this reaction Endothermic or Exothermic

Physical Science 9/22 Warm-up What is the difference between a Physical Property and a Chemical property? Give an example of a Physical Property Give an example of a Chemical Property What is an example of a Chemical Change? Test back – turn into me if you want to retest! Mini Quiz tomorrow!! Chemical changes and properties

Revisiting yesterday… Think of what you started with (the reactants) List some of the Physical properties of your starting materials Think of what you ended with (the product) List some of the Physical properties of you final material How would you identify that a chemical change occurred in this activity? What are some Physical properties of your final product? Chemical properties?

What you couldn’t see… Casein – protein in milk Acetic Acid - vinegar

Being able to distinguish between the two… As we have seen, there is a difference between physical and chemical properties. Lets generate a list… Physical Properties Chemical Properties There is also a difference between physical and chemical changes. Lets generate another list… Physical Change Chemical Change

Class work… In your packets, work on the last 4 pages This is help prepare you for your quiz tomorrow!