CHAPTER 3 – BASIC CHEMISTRY

Matter – 3 states

·       Solid –

·       Liquid –

·       Gas –

Elements –

Life elements: C, H, O, N, P, S

Atom –

Compound –

(H₂O)

Molecule –

(H₂).

COUNTING ATOMS

H₂O -> H = ___; O = ___

2(H₂O) -> H = ___; O = ___

STRUCTURE OF ATOMS:

1.            Protons:  _______________particles

2.            Neutrons: ______________ particles

3.            Electrons: ______________ particles

The Periodic Table of Elements

                6                      Atomic # (# protons)

                C                      Symbol

       Carbon       Element

      12.011         Atomic Mass (# protons + # neutrons)

# protons = # electrons 

ELECTRON MODELS – Visualizing an atom

The _________________________________________ determines how reactive the atom will be

Isotope – 
 (Carbon-14)

Radioactive isotopes:

CHEMICAL BONDS –

Atoms want to fill outer electron shells to become more stable.

1.            Ionic Bond – _________________________ Atoms become attracted as a result of oppositely charged ions. Do _______________________________ – Ions remain separate (______________________________)

Ion: _________________________________ due to gain or loss of electrons. Ex: NaCl

2.            Covalent Bond –

(____________________)

Polar – Atoms do not share electrons equally. Ex: H₂O

Nonpolar – Atoms share electrons equally. Ex: H₂

SHARING ELECTRONS BETWEEN ATOMS

Single Bonds: _________________(H – H)

Double Bonds: __________________ (O = C = O)

Triple Bonds: ___________________ (N = N)

Diatomic Molecules –

(H₂, O₂, N₂)

3.            Hydrogen Bond – Weak attraction between slightly + H atom in a molecule and a nearby slightly – atom of another molecule. (______________________________)

PHYSICAL CHANGE - Substance does not chemically change-maintains characteristic properties

·       Mixtures:

(sugar & salt)

·       Proportions can change

·       Homogeneous mixtures: substances are spread evenly throughout

·       Solvent-

(liquid)

·       Solute-

·       Dissociation:___________________________, forming separate ions.

·       Suspensions: Substances do not dissolve noticeably an _____________________________________

·       Colloidal Dispersion: Particles are_________________ ________________________________. (smoke = C particles in the air)

CHEMICAL CHANGE - Substance changes chemically.

·       Compounds:______________________________. (H₂O)

CHEMICAL REACTIONS –

·       Reactants: substances present ___________ reaction

·       Products: substances present ___________ reaction

Reactants - - - > Products

Equations must be balanced b/c of ______________________

___________________- Mass is neither created nor destroyed.

Ex:   H₂ + O₂ - - > H₂O (unbalanced)

        ________________ (balanced)

Activation Energy:

1.            Synthesis/ Dehydration – Compounds or molecules are built -> reaction produces H₂O. “___________________”

___________________________: takes in E

2.            Decomposition/ Hydrolysis – Compounds are broken down -> H₂O is added. “____________________”

___________________________: releases E

ACIDS & BASES FORM IONS WHEN DISSOLVED IN WATER

Acids: pH < 7;

Bases: pH >7;

Ions – Atoms with a ___ or ___ charge. (Na+, K+, Cl-)

Ionization –

Ex: HCl -> H⁺ + Cl-

Dissociation –

Ex: NaOH -> Na⁺ + OH-

Neutralization –

Acid + Base -> H₂O + Salt

HCl + NaOH -> H₂O + NaCl

H⁺ + OH^- -> H₂O

Salts:

Ex: HCl + NaOH -> Na⁺ + Cl^- + H₂O

_______ may be obtained from solution by ________________.

pH Scale: Determines if compound is ____________________

________ by measuring concentration of H+ ions. (p. 50 in text)

Indicator- Used to determine pH.

·       ________Paper: Red – Acid; Blue – Base; Same – Neutral

·       _____________________: Yellow -> Red = Acidic

·       _____________________: colorless -> Red = Basic

Buffers – _______________________________ during reactions that release large amounts of ions.