Chemistry, Part 4: Molecules & Bonding Science with Mr. Comans

In This Powerpoint: The Importance of Molecules What is a molecule? How do molecules impact everyday life? What molecules should you know?

In This Powerpoint: Molecule Models What is a molecular formula? What are subscripts? What are coefficients?

In This Powerpoint: Bonds How do molecules form? What kinds of bonds should you know about? What is an ionic bond? What is a covalent bond?

The Importance of Molecules Electrically neutral group of atoms held together by chemical bonds

Molecules You Should Know Water Diatomic Oxygen (the oxygen we breathe) Triatomic Oxygen (ozone) H O H O O O O O

Molecules You Should Know Glucose (Sugar) Carbon Dioxide Sodium Chloride H H H H O H O O H C C C C C C H O O H O H H H H O C O Na Cl

Molecules You Should Know Diatomic Nitrogen Diatomic Hydrogen Methane N N H H H C H H H

Molecular Formulas A molecular formula is a representation of a molecule using chemical symbols and subscripts. A subscript is a small number after a chemical symbol that represents the number of atoms in each molecule.

Molecular Formulas Water H2O Carbon Dioxide CO2 Subscript If there is no subscript after a symbol, there is only 1 atom of that element in each molecule.

Practice! See if you can guess what elements make up each molecule, plus how many atoms of each, based on the formula. O2 CaOH CH4 C7H5N3O6 H2CO3 H2SO4 Oxygen – 2 atoms Calcium – 1, Oxygen – 1, Hydrogen – 1 Carbon – 1, Hydrogen – 4 Carbon – 7, Hydrogen – 5, Nitrogen – 3, Oxygen 6 Hydrogen – 2, Carbon – 1, Oxygen – 3 Hydrogen – 2, Sulfur – 1, Oxygen - 4

Molecular Formulas A coefficient is a number placed in front of a molecular formula to indicate how many molecules are present. H2O Currently: 2 atoms of Hydrogen 1 atom of Oxygen

This bad boy multiples everything in the formula! Molecular Formulas A coefficient is a number placed in front of a molecular formula to indicate how many molecules are present. 2H2O Currently: 4 atoms of Hydrogen 2 atoms of Oxygen This bad boy multiples everything in the formula!

Molecular Formulas A coefficient is a number placed in front of a molecular formula to indicate how many molecules are present. 3H2O Currently: 6 atoms of Hydrogen 3 atoms of Oxygen

Molecular Formulas A coefficient is a number placed in front of a molecular formula to indicate how many molecules are present. 12H2O Currently: 24 atoms of Hydrogen 12 atoms of Oxygen

H H O Bonds How are these molecules held together? Why do they form in the first place? Recall: H H O

H H O Bonds How are these molecules held together? Why do they form in the first place? H H O

Bonds How are these molecules held together? Why do they form in the first place?