Elements, Compounds and Chemical Reactions (Chemical Reactions Song) (Chemical Reactions Song)

Element Definition: A pure substance made up of only one kind of atom! An atom is the basic unit of an element. The Periodic Table lists all the known elements

The Earth is Made of Elements! While the Periodic Table is HUGE, just a few of those elements make up most of our Earth. Take a look at these pie graphs!

The Earth is Made of Elements From these last two pie charts, you should be able to see that our air is mostly Nitrogen, then oxygen, our crust is mostly oxygen and then silicon, and our bodies are oxygen and then carbon. Add in the Hydrogen from water, and that’s only 5 elements out of 118 that make up most of what we know!

Element Cube On the Periodic Table, each element has an element cube that gives information about the element. The symbol is the short name for the element. Notice that for an element, there is only ONE capital letter! Sometime the chemical symbol doesn’t look like it comes from the name of the element. This happens when the symbol comes from the Latin language.

Compound A pure substance made up of two or more different elements! Compounds contain two or more capital letters, and are made up of molecules. NaCl What do you use this compound for in life?

Molecule A particle of matter in which one or more elements are joined tightly together. Molecules are the basic unit of a compound. Oxygen Hydrogen What is the name for this abundant molecule on Earth?

Physical Properties Elements and compounds have both PHYSICAL and CHEMICAL properties. A property that can be observed, measured or changed without changing the substance itself is called a physical property.

Physical Properties Examples: Odor (Smell) Color Mass Volume Density Texture How are these observed or measured?

Chemical Properties Chemical properties cannot be changed without creating a new substance. Whenever a chemical property is changed, the result will be a new substance with new chemical properties. For example: Poisonous Gas Explosive Powder Table Salt = +

CHEMICAL REACTION! A process in which one or more substances are changed into others. In a chemical reaction, a new substance is always formed! Click here to see some examples! Examples of Chemical Reactions

SIGNS OF A CHEMICAL REACTION We use the phrase ‘Please Excuse Coughs, Burps, and Sneezes’ to help remember the signs of a chemical reaction. Each capital letter stands for one of the signs. Let’s look at each one.

Evidence of Chemical Reactions PLEASE- Precipitate Formed A precipitate can form when one liquid is poured into another and a solid forms. The best known is when milk is poured into vinegar, a solid is created.

Evidence of Chemical Reactions EXCUSE- Energy Change Sometimes, Energy is absorbed by the substances causing the temperature to decrease. Example: Baking Soda/Vinegar Sometimes, Energy is released by the substances causing the temperature to increase. Example: Magic Genie demo SMOKE

Evidence of Chemical Reactions COUGHS- Color Change This is evidence of a chemical reaction only when the other properties have also changed. Example: Magic Genie, Wood burning in fireplace Chemical Change Not a Chemical Change

Evidence of Chemical Reactions BURPS- Bubbles (Gas release) When a gas is formed it may try to escape causing bubbles. The gas is a new substance. Example: Baking Soda/Vinegar

Evidence of Chemical Reactions SNEEZES- Sound & Smell Sometimes the only clue you will have of a new substance is a sound or smell. Smell is the more common of the two. Example: Baking a cake, you may smell the chemical change!

Elements Compounds

Summary When you get to this slide, pause! Either go back and review, or start working on your Left Side for these notes! Near the end of class, Mr. Huff will work with all of you to come up with a summary.