Presentation on theme: "Molecules and Compounds. Compound Formed from 2 or more elements in a specific proportion When combined, new properties are created They contain 2 or."— Presentation transcript:
Compound Formed from 2 or more elements in a specific proportion When combined, new properties are created They contain 2 or more different elements Examples: H 2 0, NaCl, CO 2
Molecule A molecule is the smallest unit of a compound They are made up of 1 or more elements The elements can either be the same or different Examples: O 2, O 3, H 2 O, CO 2
So… All compounds are molecules, BUT not all molecules are compounds. Why?
Chemical Formulas Scientists use chemical formulas to write the name of compounds It is a combination of numbers ( subscripts and coefficients) and symbols The subscript (small number) indicate how many of each atom are present The coefficient (larger number) indicate how many of each molecule is present
Example C 3 H 8 O is the chemical formula for rubbing alcohol. There are ___carbon, ___ hydrogen, and 1 oxygen atom that make up one molecule of alcohol.
Example NaCl is the chemical formula for salt There is ____ Na atom and ____ Cl atom
Example NH 3 is the chemical formula for ammonia There is ____ N atom and _____ H atoms
Example Cont. Think about it like a math problem- 4 X (CO 2 ) So there are ____ C atoms and ____ O atoms
Example 6H 2 O There are ___ H atoms and ____ O atoms
Example 3C 6 H 12 O 6 There are ____ C atoms, ____ H atoms, and ____ O atoms
Chemical Equations Chemists way of showing a chemical reaction with elements Reactant yields the product The arrow means “yields” Must be balanced (must have the same number of elements on both sides)