Chem 100 ch.1 and ch.2

chemistry

chemistry

the study of matter and the changes that matter undergoes

matter

is anything that has mass and occupies space

hypothesis

is a tentative explanation for a set of observations

law

is a concise statement of a relationship between phenomena that is always the same under the same conditions

theory

is a unifying principle that explains a body of facts and/or these laws that are based on them

scientific method

A series of steps followed to solve problems

Step 1 of Scientific Method

observation

Step 2 of Scientific Method

Identify the problem

Step 3 of Scientific Method

Research the problem

Step 4 of the Scientific Method

develop a hypothesis

Step 5 of Scientific Method

Design an experiment

Step 6 of Scientific Method

Collect and analyze data

Step 7 of Scientific Method

Draw conclusions

states of matter

solid, liquid, gas

Compound

a substance composed of atoms of two or more elements chemically united in fixed proportions

Mixture

A combination of two or more substances in which the substances retain their distinct identities

homogeneous mixture (solution)

a mixture in which the composition is uniform, hard separate

heterogeneous mixture

a mixture in which the composition varies, easy to separate

Element

a substance that cannot be separated into simpler substances by chemical means

2 substances

elements and compounds

seperating heterogenous mixtures

filtration

Seperating Homogeneous Mixtures

distillation

Crystallization

separates mixtures based on differences in solubility

Tera (T)

10^12

Giga (G)

10^9

Mega (M)

10^6

Kilo (k)

10^3

Deci (d)

10^-1

Centi (c)

10^-2

Milli (m)

10^-3

Micro (weird u)

10^-6

Nano (n)

10^-9

Pico (p)

10^-12

Celsius to Kelvin

Celsius + 273

Celsius to Fahrenheit

C=5/9(F-32)

kelvin

known as the absolute temp. scale, lowest possible temp 0K

density

mass/volume

mass

density x volume

volume

mass/density or length x width x height

physical change

state of matter changes but not the identity

example of physical change

liquid H20 vs. solid H2O

chemical change

A change in matter that produces one or more new substances

example of chemical change

water H20 to peroxide H2O2

Rule 1 of Sig Figs

All non-zero digits are significant

Rule 2 of Sig Figs

captive zeros are significant

Rule 3 of Sig Figs

trailing zeros after or before an significant number

Rule 4 of Sig Figs

leading zeros are NOT significant

Rule 5 of Sig Figs

trailing zeros before an implied decimal are ambiguous and are avoided by using scientific notation

Sig Fig Multiplication/Division

the answer has the same number of sig figs as the factor with the smallest number of sig figs

Sig Fig Addition/Subtraction

the number of sig figs in the answer is determined by the number of places after the decimal in the problem

extensive properties

a property that depends on the amount of matter in a sample

intensive properties

a property of matter that depends only on the type of matter in a sample and not on the amount

extensive properties examples

mass and volume

intensive properties example

density, boiling pt, freezing pt

unit convertion

a multi-step process that involves multiplication or division by a numerical factor, selection of the correct number of significant digits, and rounding

SI units (International System of Units)

standards fixed by international agreement in the International System of Units

What are SI units?

kg, m, s, A, K, mol, cd

accuracy

tells us how close a measurement is to the true value

precision

tells us how close multiple measurements of the same thing are to one another

Dalton

proposed the atomic theory / atom

Thomson

discovered the electron and charge to mass ratio

Thomson's experiment

Cathode Ray Tube

Rutherford

discovered the nucleus and protons

Rutherford's experiment

Gold foil experiment

Chadwick

Discovered the neutron

Bohr

electrons circular orbit around nucleus

Millican

determined charge of electron

Millican's Experiment

oil drop experiment

current model

electrons occupy regions of space around nucleus

Atomic Theory

all atoms of a given element are identical, having the same size, mass, and chemical properties (false: isotopes). One element is different from the atoms of another element

chemical reaction

rearranges atoms, doesnt create or destroy them

Proust's Law of Definite Proportions

didn't realize that elements can combine in different ratios (CO vs CO2)

Electron charge

-1

Law of Multiple Proportions (Dalton)

realized that elements can combine in different ratios

electron mass

9.10938 x 10^-28 g

proton charge

+1

proton and neutron mass

1.67493 x 10^-24

neutron charge

0

isotopes

atoms with different number of neutrons

atomic number

number of protons

columns (horizontal)

groups or families

rows (vertical)

periods

elements in pairs

H2, N2, O2, F2, Cl2, Br2, I2

atomic mass unit (amu)

a mass exactly equal to one-twelfth the mass of one carbon-12 atom

1 amu

1/12 the mass of a carbon-12 atom

find isotope mass or natural abundance

elements amu = (given amu 1)(natural abundance given 1) + (given amu 2)(natural abundance 2)

atomic weight

Average of the mass numbers of all isotopes

mass number

the sum of the number of neutrons and protons in an atomic nucleus

ion

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

cation

ion with a positive charge

anion

ion with a negative charge

how to become cation

if neutral atom LOSES one or more electrons

how to become anion

if neutral atom GAINS one or more electrons

monatomic ion

contains only one atom

polyatomic ion

contains more than one atom

oxoanions

are polyatomic anions that contain one or more oxygen atoms and one atom of another element

hydrates

are compounds that have a specific number of water molecules attached to them

acids

molecular compounds that release hydrogen ions when dissolved in water

naming binary acids

hydro + base name of nonmetal + -ic + acid

naming oxyacids

ate - ic, ite - ous + acid