1. Changes in Matter Physical Change - when a substance is changed, yet retains its composition ex. sheet of aluminum foil rolled up into a ball, smashing a crystal, or cutting paper Phase Change - transition from one state to another, still a physical change, based on temperature and pressure of the surroundings

2. Changes in Matter Physical Change - Water Cycle is a great example of physical changes. as water goes through different pressures and temperatures, it is seen in its 3 phases (solid, liquid, and gas)

3. Changes in Matter Physical Changes Melting Point - temperature and pressure at which a solid phase changes to a liquid Boiling Point - temperature and pressure at which a liquid phase changes to a gas ex. what are the boiling and melting points of water? Melting and Boiling points are intensive properties that can be used to identify unknown substances through experimentation.

4. Changes in Matter Chemical Change - process that involves one or more substances changing into different substances commonly referred to as a chemical reaction the "new" substance formed from a chemical reaction has different properties than the substances did before the reaction the substances involed before the reaction are called REACTANTS the substances created through the reaction are called the PRODUCTS

5. Changes in Matter ex. when iron is left exposed to air containing oxygen, a reaction occurs creating rust (iron oxide) which has different properties than either the iron or the oxygen the rust is not attracted to magnets, while the iron is ex. when food spoils, the look, feel, smell, and taste of the new product differ from the original food, as well as the digestability of the spoilt food

6. Changes in Matter Conservation of Mass late 1700s - development of more precise scales measurements during reactions showed that total mass before and after reactions was constant, no change in mass LAW OF CONSERVATION OF MASS developed from the findings, stating that mass is neither created or destroyed during a chemical reaction, it is conserved. in other words, the total mass of reactants will equal the total mass of the products

7. Changes in Matter example - In an experiment, 10.00g of red mercury oxide powder is heated in an open flask until it is converted to liquid mercury and oxygen gas. The liquid mercury has a mass of 9.26g. What is the mass of the oxygen gas formed in the reaction? Mass reactants = Mass products 10.00g (mercury oxide) = 9.26g (mercury liquid) + ____ g (oxygen gas) 10.00g - 9.26g = 0.74g