Chem110 Exam 1

mass

measure of the resistance of an object to a change in its state of motion

weight

force extended by gravity on an object

deci

.1

centi

.01

mili

.001

1dm³

1000 cm³

1cm³

1 mL

law

statement of observed behavior

theory

attempt to explain why something happens

natural law

observed measurable behavior

steps of scientific method

make observations, formulate hypothesis, perform experiments

accuracy

agreement of a particular value with the true value

precision

degree of agreement among several measurements of the same quantity

(sig figs) Non zero digits

always sig fig

(sig figs) leading zeros

never sig fig

(sig figs) captive zeros

always sig fig

(sig figs) trailing zeros

only sig fig if the number has a decimal point

(sig figs) exact numbers

infinite number of sig figs

sig fig rules for addition or subtraction

result has same number of decimal places as the least precise measurement in equation

sig fig rules for multiplication or division

result has the same amount of sig figs as the least precise measurement in the equation

density

d=m/v

matter

anything that has weight and takes up space

homogenous mixture

parts cannot be seen

heterogenous mixture

parts can be seen

properties of a solid

rigid, fixed volume and shape, slightly compressible

properties of a liquid

definite volume, no specific shape, slightly compressible

properties of a gas

no fixed volume or shape, highly compressible

mixture

has variable composition, can be separated into pure substances, behaves the same as before they were mixed and after being separated

physical change

change in form, no change in chemical substance, used to separate mixture into compounds

3 methods of separating components in a mixture

distillation, filtration, chromatography

distillation

depends on boiling point, heating the mixture, vapor is passed through condenser where it returns to liquid state

filtration

used when mixture contains a solid and a liquid; liquid passes through filter, solid stays behind

chromatography

mobile phase, stationary phase; separation occurs because the components have different affinities for the two phases

compound

pure substance with a constant composition that can be broken down into its elements

element

pure substance that cannot be further broken down by physical or chemical means

law of multiple proportions

when two elements form a series of compounds, the ratios of the masses of the second element that combine with the 1g of the first elements can always be reduced to small whole numbers

dalton’s atomic theory

each element is made up of atoms, atoms of any given element are identical, chemical compounds are formed when atoms of two elements combine, chemical reactions involve the reorganization of atoms

cathode ray

cathode ray was a stream of electrons

radioactivity

discovered through spontaneous emission by uranium

gamma rays

high energy light

beta particles

high speed electrons

alpha particles

particles with 2+ charge

protons

positive charge, in the nucleus of the atom, amount determines the element

electron

negative charge, in the electron cloud around the nucleus of the atom

isotope

atoms with the same number of protons but different numbers of neutrons

covalent bond

sharing of electrons

chemical formula

uses symbols of elements to indicate types of atoms present in the molecule, subscripts indicate relative number of atoms

ion

atom or group of atoms with a negative or positive charge

cation

positive ion formed by losing electrons

anion

negative ion formed by gaining electrons

ionic bond

force of attraction between oppositely charged ions

alkali metals

Grp 1A, lose 1e to form 1+ ion

alkali earth metals

grp 2A, loses 2e to form 2+ ion

halogens

grp7A, form diatomic molecules

noble gases

grp8A, normal conditions under monatomic gases, little chemical reactivity

Diatomic Elements

HOFBrINCl (hydrogen, oxygen, fluorine, bromine, iodine, nitrogen, chlorine)

binary compounds

composed of 2 elements, some include covalent and ionic compounds

binary ionic compounds

contain a cation (written first), and an anion

type of compound if compound starts with a metal or polyatomic

ionic

type of compound if compound starts with nonmetal

moelcular/covalent

type of compound if compound starts with H

acid (except water)

grp 1A form charge

1+

grp 2A form charge

2+

Al charge

3+

Ag charge

+

Zn charge

2+

Cr, Mn, Fe, Co charges

2+ or 3+

Cu charges

2+ or +

Cd charge

2+

Sn and Pb charges

2+ or 4+

naming polyatomic ions

use prefix hypo- to name members in series with fewest O atoms, use prefix per- to name members with most O atoms

OH-

hydroxide

NO3

nitrate

SO4

sulfate

NH4+

ammonium

PO4³-

phosphate

C2H3O2

acetate

CO3²-

carbonate

binary covalent

between 2 nonmetals, name with prefixes

Naming Acids

depends on whether O is present; if anion ends in -ide - prefix hydro and sufficx-ic; anion contains O - root name of anion suffix -ic (ate) or -ous (ite)

formula F to C

(F-32)5/9

formula C to F

(Cx9/5)+32

formula K to C

C + 273.15

formula C to K

K - 273.15

results of rutherford

atoms is mostly open space with a dense nucleus

results of milikan

determined that all electrons are the same in mass and charge

results of thomson

determined that electrons are negative