Chemistry A Exam Review

mass number =

number of protons + number of nuetrons

number of protons is called

atomic number (found on periodic table)

when writing chemical formulas

it will be correct if the charges balance to zero (Example: Copper(I) Chloride is CuCl because Copper (I) has a charge of 1+ and Chloride has a charge of 1-)

For covalent compounds

\-A compund with NO metals

\-The prefix determines the subscript in the formula

\-Add “ide” to the ending of the second element

\-(Example: P3O6 = Triphosphorus Heoxide)

Prefixes for covalent compounds

\-The prefix determines the amount of atoms present

\-Mono: 1

\-Di: 2

\-Tri: 3

\-Tetra: 4

\-Penta: 5

\-Hexa: 6

\-Hepta: 7

\-Octa: 8

\*\*NOTE: Never use “mono” with the FIRST element

\*\*NOTE: Avoid having two vowels in a row by dropping the vowel from the prefix, HOWEVER, never drop “i” from di or tri.

What’s a scientific hypothesis?

A possible explination for an observation

Heterogeneous Mixture

\-DOES NOT look the same throughout (hint: hetero relatoships are a dude and a girl, different genders)

\-It’s contents AREN’T evenly distributed

Examples of heterogeneous mixtures

Salad, Trail Mix

Homogeneous Mixture

\-DOES look the same throughout (Hint: homo reationships are 2 of the same gender)

\-Its contents ARE evenly distributed

examples of homogeneous mixtures

Vinigar, Gasoline, Miscible liquids (liquids that can be mixed wthout separating/ ispropyl alchohol & water)

Physical changes

something that effects only the phyical properties of a substance, the substance is still the same after the change

examples of physical changes

dissolving, breaking, cutting, melting/freezing/boiling (changing state)

chemical changes

when one or more substances are completly changed into a new substance with different properties

Examples of chemical changes

rusting, burning, rotting, tarnishing

metalliods

\-Share properties with metals and non metals

\-can conduct electrcity under some conditions

\-found on stair step of periodic table

metals

\-shiny

\-ductile (wires)

\-malleable (hammer into different shapes)

\-good conductors of heat and electricty

\-found on left side of periodic table

nonmetals

\-not shiny

\-not ductile

\-not malleable

\-poor conductors of heat and electricty

\-mainly gases

\-found on right side of periodic table

the nucleus of an atom

\-very small compared to the overall size

\-has almost all the mass of an atom

\-positivly charged

\-dense

isotopes

two atoms that have the same number of protons but a different number of nuetrons

cation

positive ion

anion

negative ion

chemical compounds

atoms of one element combine with atoms of other elements

what are some signs that a chemical reaction has occured?

color change, solid (percipitate) forms, bubbles form, heat or flame is produced or absorbed

synthesis

when 2 reactants turn into one product

decomposition

when one reactant turns into two products

combustion

when CO2 and H20 are the produts

single displacement

when only one element is switched in the products

double displacement

when both sets elements are switched in the products