Chapter 2.1 Notes September 8, 2014 Grab a textbook and return quietly to your seat Write your EQ at the top of page 26 in your journal “What is the relationship between elements and compounds?”

When you enter….. Grab a textbook and return quietly to your seat Write your EQ at the top of page 26 in your journal “What is the relationship between elements and compounds?”

Vocabulary  Use KIM Notes to define the following words: 1. Substance 2. Molecule 3. Compound 4. Chemical Formula 5. Ratio

Matter  Matter is anything that has mass and takes up space  A substance is a single kind of matter that is pure meaning that it always has a specific makeup and set of properties  Examples- sugar, table salt  Non-examples- butter, milk

Physical Properties  Properties of a pure substance that can be observed without changing it into another substance  Examples: Hardness, Texture, Color, State of Matter, Flexibility, Conductivity Diamonds are the hardest natural material Flexibility

Chemical Properties  A characteristic of a pure substance that describes its ability to change into a different substance  Properties include flammability and reactivity

Question:  What must you do to observe a chemical change?

Think….Pair…..Share  Helium does not react with any other substance. Is it accurate to say that helium has no chemical properties?

Elements  Are the simplest substances  All matter in the universe is made up of slightly more than 100 elements  An element cannot be broken down into any other substance by chemical or physical means  An atom is the basic particle from which all elements are made

When atoms combine  Atoms combine with a chemical bond to form larger particles called molecules- two or more atoms held together by a chemical bond  FaHbIXg FaHbIXg

Compounds  Most elements are found in nature combined with other elements.  A compound is a pure substance made of two or more elements chemically combined in a set ratio  (Read Math Skills Box p.40)  Represented by a chemical formula which shows the elements and the ratio of atoms  Compounds have different properties from those that are uncombined elements (Ex: Na is very reactive, table salt-NaCl- is not)

Mixtures  Most materials are not pure substances (elements or compounds)  A mixture is made of two or more elements or compounds that are not chemically combined or combined in a set ratio  Each substance in a mixture keeps its individual properties

Types of Mixtures Heterogeneous  You can see the different parts Homogeneous  So evenly mixed that you can’t see the different parts  Example: Solution

Question…  Why is it correct to say that sea water is a mixture?

Scientific Scramble

Video  ZwNLvPA ZwNLvPA