January 7, 2019

Chapter 6/7Chemical Structure

& Reactions

January 7, 2019

6.1: Compounds & Molecules A) Chemical Bonds

> Compounds– All particles the same, but made up of different elements– Has properties different than elements that make it up

» ex: NaCl

> Chemical Bonds– force (energy) that holds atoms or ions together– can bend, stretch & rotate without breaking

» Break or Build Bonds / Rearrange atoms = Reaction

6.1: Compounds & Molecules Cont. B) Chemical Structure

– the way the compound's atoms are bonded/arranged– use models to help draw

> Ball & Stick Model– Bonds = Sticks

« angles and distances help explain properties

> Space Filling Model– Shows relative sizes of atoms

January 7, 20196.1: Compounds & Molecules Cont. C) Bond Types

– Atoms form bonds to become stable or fill outer shell

> Ionic Bond– Atom gives electron to

different atom– Oppositely charged ions attract

> Covalent Bond– Atoms share a pair of

electrons– Since both atoms hanging

on to electrons, atoms are held together

> Hydrogen Bond– Weak attraction of the negative side of one

molecule to the positive side of another

January 7, 2019

6.1: Compounds & Molecules Cont. D) Structure & Properties

– Structure determines Properties» Strong bonds = Strong molecules

> Network of Bonded Atoms– bonds are same angles & arrangement throughout – known as strong solids & have high Melting/Boiling

points» Ex: Quartz

> Network of Bonded Ions– Ions are held together in

network structure– Held together by opposite

charges– strong structures leading to

High Melting/Boiling points

> Molecule Compounds– made up of many molecules of substance (SUGAR)– weak attraction between molecules

» lower melting/boiling points

7.1: Nature of Chemical ReactionsA) Chemical Reaction: matter chemically changes into new substance

> Chemical Equation: show how atoms/ions are rearranged – Reactants rearranged into products– Mass & Energy are conserved– Energy is needed to build bonds– Energy is released when breaking bonds

January 7, 2019

7.1: Nature of Chemical Reactions Cont. B) Reaction Energy

> Reactions that release energy are Exothermic Reactions– energy release from...

> Reactions that require energy are Endothermic Reactions– energy used to...

7.3: Types of Chemical Reactions A) Classifying Reactions

> able to predict product from reactants using common reactions

B) Basic Reaction Types

1: Synthesis Reaction» Two or more reactants combine to form more

complex product

2: Decomposition Reaction» One Reactant broken down into two or more simpler

products

January 7, 2019

7.3: Types of Chemical Reactions Cont. B) Basic Reaction Types Cont.

3: Single-Displacement Reaction» One element takes the place of another element in

a compound

4: Double-Displacement Reaction» Two compounds exchange atoms or ions