General Chemistry 1 Exam 1

Scientific Method

1) Identifying a question, developing a hypothesis 2) Perform experiment, make observations, record data 3) Interpret data, general hypothesis 4) Collect more data, maybe develop law or theory

Law

A statement that summarizes past observations and is used to predict future ones.

Theory

A possible explanation or a law

Solid

Fixed shape and volume

Liquid

Fixed volume, no fixed shape

Gas

No fixed volume or shape, Compressible.

Homogeneous Mixture

The composition of the mixture is the same throughout

Heterogeneous Mixture

The composition is not uniform

Pure Substance

A material that is composed of only one type of particle

Mixtures

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

Decanting

To carefully pour off

Filtration

To separate using a physical boundary

Distillation

To separate via boiling point difference

Physical Change

Does not change composition

Chemical Change

Does change composition

Celsius to Fahrenheit

F=1.8C+32

Celsius to Kelvin

K=C+273.15

Significant Figures: Multiplication/Division

The total # of S.F in the answer is equal to the least # that appears in a measurement

tera (T)

10^12

mega (M)

10^6

kilo (k)

10^3

deci (d)

10^-1

centi (c)

10^-2

milli (m)

10^-3

micro (μ)

10^-6

nano (n)

10^-9

pico (p)

10^-12

Derived Unit

A unit derived from fundamental units of length, mass, and time.

(1cm^3=1mL)

Accuracy vs. Precision

Random Error

Error that is not repeatable and lead to fluctuations in results.

Repetitions of the same experiment lead to different results.

Systematic Error

Error that is repeatable and means that the experimental measurements are centred on the wrong target

J.J. Thomson

Discovered the electron (cathode ray tube experiment)

Robert Millikan

Discovered the charge and mass of the electron

(negative, 0.00055 amu) Via oil drop experiment

Ernest Rutherford

Discovered nuclear model of the atom via gold foil experiment.

Atomic Theory Postulates

-Matter is composed of very tiny or microscopic particles called "Atom".

-Atom is an indivisible particle.

-Atom can neither be created nor it is destroyed.

-Atoms of an element are identical in size, shape, mass and in other properties.

-Atoms of different elements are different in their properties.

-Atoms combine with each other in small whole numbers.

-All chemical reactions are due to combination or separation of atoms.

Atomic Number

Same as number of protons

H

Hydrogen

He

Helium

Li

Lithium

Be

Beryllium

B

Boron

C

Carbon

N

Nitrogen

O

Oxygen

F

Fluorine

Ne

Neon

Na

Sodium

Mg

Magnesium

Al

Aluminium

Si

Silicon

P

Phosphorus

S

Sulfur

Cl

Chlorine

Ar

Argon

K

Potassium

Ca

Calcium

Sc

Scandium

Ti

Titanium

V

Vanadium

Cr

Chromium

Mn

Manganese

Fe

Iron

Co

Cobalt

Ni

Nickel

Cu

Copper

Zn

Zinc

Ga

Gallium

Ge

Germanium

As

Arsenic

Se

Selenium

Br

Bromine

Kr

Krypton

Rb

Rubidium

Sr

Strontium

I

Iodine

Xe

Xenon

Cs

Cesium

Ba

Barium

At

Astatine

Rn

Radon

Fr

Francium

Ra

Radium

Pt

Platinum

Hg

Mercury

Pb

Lead

Sn

Tin

Bi

Bismuth

Ag

Silver

Au

Gold

W

Tungsten

U

Uranium

Sb

Antimony

Isotopes are dependent on

The number of neurons

Cation

e-

Anion

e->p+

Avagadro's Number

6.022X10^23

1 amu=

1g/mol

Atomic Element

Pure substance

Molecular element

Two or more atoms together

Covalent Bond

-2 non metals

-metalloid/non metal