Unit 0 Ap Chem

H2

Hydrogen - Gas

N2

Nitrogen - Gas

O2

Oxygen - Gas

F2

Fluorine - Gas

Cl2

Chlorine - Gas

Br2

Bromine - Liquid

I2

Iodine - Solid

1 - H

Hydrogen

2 - He

Helium

3 - Li

Lithium

4 - Be

Beryllium

5 - B

Boron

6 - C

Carbon

7 - N

Nitrogen

8 - O

Oxygen

9 - F

Fluorine

10 - Ne

Neon

11 - Na

Sodium

12 - Mg

Magnesium

13 - Al

Aluminum

14 - Si

Silicon

15 - P

Phosphorus

16 - S

Sulfur

17 - Cl

Chlorine

18 - Ar

Argon

19 - K

Potassium

20 - Ca

Calcium

26 - Fe

Iron

29 - Cu

Copper

35 - Br

Bromine

47 - Ag

Silver

50 - Sn

Tin

53 - I

Iodine

56 - Ba

Barium

79 - Au

Gold

80 - Hg

Mercury

82 - Pb

Lead

SO4^2-

Sulfate

NO3^-

Nitrate

CO3^2-

Carbonate

C2H3O2^-

Acetate

PO4^3-

Phosphate

OH^-

Hydroxide

NH4^+

Ammonium

HCO3^-

Bicarbonate (Hydrogen carbonate)

Science

Framework for gaining and organizing knowledge; a procedure for processing and understanding certain types of information

Hypothesis

A possible explanation for an observation

Theory (model)

A set of tested hypotheses that gives an overall explanation of a natural phenomenon; a human invention that attempts to explain why something happens

Natural law

A summary of observed (measurable) behavior; states what happens, not why

Law vs. Theory

A law summarizes what happens (observed behavior); a theory is a human invention that attempts to explain why it happens

Qualitative observation

An observation that does not involve numbers

Quantitative observation

A measurement that involves both a number and a unit

Law of conservation of mass

The total mass of materials is unaffected by a chemical change in those materials

Atomic number

The number above every element symbol on the periodic table

Metals

Efficient conductors of heat and electricity, malleable, ductile, lustrous; tend to lose electrons to form positive ions

Nonmetals

Lack the physical properties of metals; tend to gain electrons to form negative ions; often bond to each other with covalent bonds

Groups (families)

Vertical columns on the periodic table containing elements with similar chemical properties

Periods

Horizontal rows of elements on the periodic table

Alkali metals

Group 1A elements; very active, readily form ions with a 1+ charge when reacting with nonmetals

Alkaline earth metals

Group 2A elements; form ions with a 2+ charge when reacting with nonmetals

Halogens

Group 7A elements; form diatomic molecules; react with metals to form salts with a 1– charge ion (except astatine)

Noble gases

Group 8A elements; exist as monatomic gases under normal conditions with little chemical reactivity

Binary compound

A compound composed of two elements; can be covalent or ionic

Binary ionic compound

Contains a cation (written first in the formula) and an anion

Naming binary ionic compounds (Type I)

Cation is named first (from the parent element name), anion is named second (root of element name + -ide)

Binary ionic compounds (Type II)

Naming for metals that form more than one type of cation; the charge of the metal cation is shown with a Roman numeral

Elements that don't need Roman numerals

Group 1A (1+ ions), Group 2A (2+ ions), Aluminum (Al3+), Silver (Ag+), and Zinc (Zn2+)

Oxyanion

An anion that contains an atom of a given element plus different numbers of oxygen atoms

Oxyanion naming (2 in series)

Smaller number of O atoms ends in -ite; larger number of O atoms ends in -ate

Oxyanion naming (more than 2 in series)

hypo- prefix = fewest O atoms; per- prefix = most O atoms

Binary covalent compound (Type III)

Formed between two nonmetals; first element uses full name, second is named as if an anion, with prefixes showing number of atoms

Prefix rule for binary covalent naming

The prefix mono- is never used for the first element in the name

Acid naming - anion ends in -ide

Named with the prefix hydro- and the suffix -ic

Acid naming - anion ends in -ate

Suffix -ic is added to the root name of the anion

Acid naming - anion ends in -ite

The -ite ending is replaced with -ous

Imperial system

System of units used in the United States

SI system

International System of units; based on the metric system

Certain digits

Numbers in a measurement that remain the same regardless of who measures them

Uncertain digit

The digit in a measurement that must be estimated and therefore varies

Significant figures

The certain digits plus the first uncertain digit recorded in a measurement

Meniscus

The curve at the bottom of a liquid's surface, read to measure volume (e.g., in a buret)

Accuracy

Agreement of a particular measured value with the true value

Precision

Degree of agreement among several measurements of the same quantity; represents reproducibility

Random error

Error where a measurement has equal probability of being high or low; occurs in estimating the last digit

Systematic error

Error that occurs in the same direction every time (always high or always low)

Leading zeros

Zeros that precede all nonzero digits; never count as significant figures (e.g., 0.0025 has 2 sig figs)

Captive zeros

Zeros between nonzero digits; always count as significant figures (e.g., 1.008 has 4 sig figs)

Trailing zeros

Zeros at the right end of a number; significant only if the number contains a decimal point (100 has 1 sig fig, 1.00×10^2 has 3 sig figs)

Exact numbers

Numbers determined by counting, not measuring; assumed to have infinite significant figures

Sig figs in multiplication/division

Result has the same number of significant figures as the least precise measurement used

Sig figs in addition/subtraction

Result has the same number of decimal places as the least precise measurement used

Rounding rule (< 5)

If the digit to be removed is less than 5, the preceding digit stays the same

Rounding rule (≥ 5)

If the digit to be removed is 5 or greater, the preceding digit is increased by 1

Dimensional analysis (Unit Factor Method)

A method that helps convert a given result from one system of units to another using unit factors