Chemistry Final

isotope notation

ex. C-14 : the number is the same as the mass number

mole

unit for measuring large quantities of atoms/molecules

molecular formula

the number of atoms of each element in a compound

empirical formula

the simplest or most reduced ratio of atoms in a compound

percent composition

the percent by mass of each element in a compound

relative mass

**the mass of an atom or molecule compared to that of 1/12 of a carbon-12 atom**.

avogadro’s hypothesis

At the same temperature and pressure, equal volumes of different gases contain the same number of molecules.

hoffman apparatus

separates water into 2 different gases using electricity

distillation

the process of separating the components of a liquid mixture through selective evaporation and condensation

Matter

anything that has space/takes up space

gases

particles are independent widely separated, with no attractive forces between them. They fill the volume of the container

liquid

particles constantly make and break temporary attractions between each other, particles can slip past one another easily, they take the shape of the container

solid

strong attractions between particles lock them into a fixed arrangement

pure substance

these have fixed compositions, one set of intrinsic physical properties (density etc) can be separated only by chemical means

mixtures

these have variable composition, their physical properties vary depending on the composition, they can be separated by physical means

elements

type of matter where all atoms are the same

compounds

type of matter made from 2 or more elements that have chemically bonded so the new properties are different from the original elements

molecule

two or more atoms that are chemically bonded

homogenous

all samples take from the same mixture are identical

heterogeneous

two samples from the same mixture that are not identical (2-3 phase mixture)

suspension

2 phase mixture where the solids will settle out over time

colloid

2 phase mixture that does not seperate

solution

single phase mixture

decanting

the separation of mixtures of immersible liquids or of a liquid and a solid mixture

mass number

protons + neutrons

atomic size/ atomic radius (volume)

as you go left to right the volume decreases because as you go across you are adding more protons making the attraction strong as you go down a group the volume increases because of the added energy levels

ionization energy

as you go across the rows the energy increases because it takes more energy to remove electrons from levels. going down a group it decreases because the atom is getting bigger

electronegativity

the attraction between the nucleus of an atom and the shared electrons in a chemical bond with another atom (increases left to right because the forces get stronger and decreases down a group)

electron affinity

the energy released when an electron is added to an atom (increase left to right and decreases down a group)

Copper (II) Chloride lab

evidence:

* chlorine gas/bubbles formed on positive electrode
* negative electrode turned orange
* solution started becoming lighter on negative side

Outcome: metals (copper) form positives, nonmetals (chlorine) form negatives

ionic compounds

metal and a nonmetal exchange electrons; high melting and boiling points and conduct electricity, takes more energy to break the bond

covalent compound

nonmetal and nonmetal share electrons; lower melting and boiling point and don't conduct energy

anion

A negatively charged ion

cation

A positively charged ion

ion

An atom or group of atoms that has a positive or negative charge

polyatomic ion

A charged group of covalently bonded atoms (many)

polar molecule

molecule with an unequal distribution of charge, resulting in the molecule having a positive end and a negative end

nonpolar molecule

molecule that shares electrons equally and does not have oppositely charged ends

Law of definite proportions

a given compound always has the same proportion of its constituent elements by mass

law of multiple proportions

when two elements A and B form two different compounds, the masses of element B that combine with a fixed mass of element A can be expressed as a ratio of small whole numbers

polarization of charge

One side of material is charged slightly more positive or negative than the other

\- occurs to neutral conductor when it comes into contact with charged conductor

polar bond

any bond between two atoms where the electronegativity difference is between 0.5 and 2.0

non polar bond

a bond between two atoms where the electronegativity difference is less than 0.5

ionic bond

any bond where the electronegativity difference is 2.0 or greater

linear

trigonal planar

tetrahedral

bent

trigonal pyramidal