Chemical Reactions Cornell Notes page 127 Chemical Properties

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Chemical Reactions Cornell Notes page 127

Chemical Reactions Cornell Notes page 127

Chemical Properties n Characteristics of a material that can only be determined during a

Chemical Properties n Characteristics of a material that can only be determined during a Chemical Reaction – Reactivity – Flammability – p. H – Oxidation

Chemical Reaction n The Reactants n Substances Products n New process of substances changing

Chemical Reaction n The Reactants n Substances Products n New process of substances changing into new substances. at start of reaction that are changed substances made from the reaction (end results).

The Law of Conservation of Matter n Matter is not created or destroyed. n

The Law of Conservation of Matter n Matter is not created or destroyed. n mass of reactants should equal mass of products!

4 Signs of a Chemical Reaction n Used to identify when a reaction has

4 Signs of a Chemical Reaction n Used to identify when a reaction has occurred n Not definite- more signs increase confidence that a reaction has occurred. n Best indicator is that substances have new properties.

4 Signs of a Chemical Reaction 1. Formation of a Gas n Bubbles n

4 Signs of a Chemical Reaction 1. Formation of a Gas n Bubbles n Least reliable sign Ex. ) baking soda and vinegar; yeast and hydrogen peroxide.

4 Signs of a Chemical Reaction 2. Formation of a Precipitate n Solid is

4 Signs of a Chemical Reaction 2. Formation of a Precipitate n Solid is created when two liquids are mixed n May look like small particles suspended in a liquid.

4 Signs of a Chemical Reaction 3. Unexpected Color Change n When two substances

4 Signs of a Chemical Reaction 3. Unexpected Color Change n When two substances are mixed an unexpected color occurs. Ex. ) Bleach spilt on colored clothes.

4 Signs of a Chemical Reaction 4. Temperature Change n temperature changes as energy

4 Signs of a Chemical Reaction 4. Temperature Change n temperature changes as energy is used or released from the reaction. n Exothermic- heat is released (gets warmer) n Endothermic- heat is absorbed (gets colder)

What is a Catalyst? n. A substance that starts or speeds up a chemical

What is a Catalyst? n. A substance that starts or speeds up a chemical reaction that is not used or changed in the reaction. n lowers the amount of energy needed in a chemical reaction

Oxidation Reactions Page 127

Oxidation Reactions Page 127

Oxidation • Specific type of Chemical Reaction in which a Reactions substance reacts with

Oxidation • Specific type of Chemical Reaction in which a Reactions substance reacts with oxygen • Often results in a color change – Apples turn brown – Many metals oxidize, such as iron turning red or copper turning green; we often call this rust.

 • Oxygen reacts with iron to create rust. • The new color is

• Oxygen reacts with iron to create rust. • The new color is evidence that a chemical reaction has taken place.

 • Oxygen reacts with apples to cause them to brown • Adding citric

• Oxygen reacts with apples to cause them to brown • Adding citric acid prevents the oxidation reaction.

 • Oxygen reacts with copper to create a green color called verdigris •

• Oxygen reacts with copper to create a green color called verdigris • Many oxidation reactions take time to happen.

 • Burning is an example of a rapid oxidation reaction. • Oxygen is

• Burning is an example of a rapid oxidation reaction. • Oxygen is required for burning, the heat and light are evidence that a reaction is taking place.