Chemistry Topic 2

Formulas and Equations

• Chemistry – Mr. Sinto

• Topic 2 – Formulas and Equations

• Obj: Understand the information contained within formulas

• Do Now: What did you learn from the test? How can you better prepare or continue to do well?

Chemical Symbols and Formula

• Each element has a 1, 2, or 3 letter symbol

• FIRST LETTER IS CAPITALIZED

• Second letter lower-case

• Co vs. CO

Diatomics • Two of the same elements bonded together

(can be alone with other elements).

• MUST MEMORIZE!!!!

•Br2, I2, N2, Cl2, H2, O2, F2

Chemical Formulas

• Qualitative = information that’s not measured

• Quantitative = information measured

• Formulas give us both types of info

• Ex. CaCl2

– Qualitative = calcium and chlorine are present

– Quantitative = 1 calcium and 2 chlorine

Types of Formulas • Empirical

–Most reduced ratio of atoms

– Ex. CH2O

• Molecular

–A multiple of an empirical formula (usually the actual formula)

– Ex. C6H12O6

Atoms, Compounds, and Ions

• Atoms and compounds = NEUTRAL

• Ions = charged (+ or -)

–If just + or - it’s +/-1

–Have gained or lost ELECTRONS to get charge

Polyatomic Ions

• A group of atoms with a charge (charge belongs to whole group)

• Table E

Formulas

• Subscripts belong to element right before it (or parenthesis before it)

• Coefficient belongs to whole group

• Dot (•) means add

• Ex. 3 Ca(OH) 2

Elements, Compounds, Mixtures

Exit Ticket – On loose leaf to hand in

• For each example give the number of atoms of each element

• Ex. BaBr2 = 1 Ba, 2 Br

1. NaBrO

2. HF

3. H3PO4

4. 2 NO3

5. CuSO4 • 5H2O

• Chemistry – Mr. Sinto

• Topic 2 – Formulas and Equations

• Obj: Create compounds based on the charges of its components

• Do Now: How many atoms of Oxygen (O) are there in the following example:

• 3 Al2(SO4)3

• Homework: Worksheet (2 sides)

Writing Formulas and Naming Compounds

• To create a compound take the charges (ignore the signs) of the ions and make them the subscripts, then reduce.

` • USE () FOR POLYATOMICS WHEN SUBSCRIPT ISN’T 1

Ca2+ NO3- NH4

+ CO32-

Na+ SO42-

Al3+ OH-

• Chemistry – Mr. Sinto

• Topic 2 – Formulas and Equations

• Obj: Name compounds and balance equations

• Do Now: What is the law of conservation of matter?

• Homework: Memorize first 20 elements on periodic table

• Print out reference tables by Thursday

Naming Compounds

• To name a compound keep the name of the first element the same and end the second element with “-ide”

• KEEP NAMES OF POLYATOMICS THE SAME ALWAYS!!!

• Put the most electronegative element last (use reference tables)

• If the metal has more than one oxidation state (periodic table) put the number as a Roman numeral in parenthesis.

Physical and Chemical Change

• Physical change - does not result in a new substance being formed

• Ex. phase changes and dissolving

• Chemical change - results in a new substance

• Ex. burning, rusting, any chemical reaction

Chemical Reactions

• Reactant = anything to the left of the arrow

• Product = anything to the right of the arrow

Endothermic and Exothermic

• Endothermic reactions absorb energy and have a positive ΔH (energy is a reactant)

• Exothermic reactions release energy and have a negative ΔH (energy is a product)

• Use Table I to look up

ΔH values.

Balancing Equations

• NUMBER OF ELEMENT’S TOTAL ATOMS MUST BE THE SAME ON BOTH SIDES OF EQUATION!!!

• Chemistry – Mr. Sinto

• Topic 2 – Formulas and Equations

• Obj: Differentiate between different types of chemical reactions

• Do Now: Take out the reference tables you printed out and Balance these:

Synthesis

•A + B AB • Multiple reactants, one product

Decomposition (AKA Analysis)

•AB A + B • One reactant, multiple products

Single Replacement

•AB + C A + CB

Double Replacement

•AB + CD AD + CB

Mass is conserved!!!

•TOTAL MASS OF REACTANTS = TOTAL MASS OF PRODUCTS!!!

Class Work / Exit Ticket

• Do 1-5 on loose leaf

• Copy from board

• Copy questions first then start working on them

Test Rules

• You get 1 Zipgrade (you will use this for other exams)

• DO NOT WRITE ON REFENCE TABLES, YOU HAND THEM BACK!!!!

• Put your name on both multiple choice and extended response

• v1 = A v2 = B on zipgrade for multiple choice KEY

New Punishment Essay

• In a class that you have a test in the next day, explain how it makes sense to fool around during test review.

• Must be 1 page, double spaced, 1 inch margins, Times New Roman, size 12 font