College Chemistry TEST 1

Chemistry

Study of atoms and their interactions

what is the scientific method

A procedure for processing and understanding information gathered during experimentation

What is the steps to the scientific method

Observation, research, Hypothesis, Experiment, Conclusion, theory, Natural law

Natural Law

Theory that has been tested and never proven incorrect

what is mass

The amount of space an object occupies.

what is weight

The measure of the pull of Earth on an object.

1mL=

1=cm³

meniscus

All liquids will have a curve when in containers, so measure from the bottom of the curve

uncertainty in measurements?

Markings on equipment only allow for so many decimal places to be read

Accuracy

How close a measurement is to the actual measurement.

precision

How reproducible a measurement is

random error

error that has an equal probability of being high or low

What is a systematic error

same error each time,Mostly because of some repeated error.

What is a Significant figure?

The digits in a measurement that are known with certainty plus the first digit that is uncertain

Why do we use sig figs?

To keep answers from claiming to be more precise than the measurements will allow

What is temperature?

a measure of the average kinetic energy of translation

What is density

the mass per unit volume

D=

m/v

M=

DxV

V=

M/D

What is a homogeneous mixture?

Two or more substances in a mixture that are evenly mixed

What is a heterogeneous Mixture?

Two or more substances in a mixture that visibly has distinguishable parts.

what is Distillation?

uses boiling points of two different substances to separate

What is filtration

separates between a solid and a liquid.

What is a compound?

A substance that is made up of elements, but can still be broken down.

element

Substances that cannot be decomposed into simpler substances

chemical change

A substance becomes a new substance with different properties  and different compositions

What is a physical change?

A change in state of the substance occurs, but the properties and compositions are still the same

What happened in 1000 BC

chemistry was used to mix and melt metals to make stronger weapons

Who was the first to come up with the idea that atom is the smallest indivisible part of particles?

The Greeks

Democritus

cretited with the word Atomos

Alchemy

an ancient traditional branch of natural philosophy and a precursor to modern chemistry that focused on turning basic metals into gold, curing diseases, and extending life indefinitely

Law of Conservation of Mass

Mass is neither created nor destroyed

Who created the law of conservation of mass

Antoine Lavoisier

Law of definite Proportions

A given compound always contains exactly the same proportions of elements by mass

Who created the law of definite Proportions

Proust

Law of multiple proportions

Elements will always combine in whole number ratios

who created the law of multiple proportions

John Dalton

What are the four postulates of Daltons Atomic Theory

Each element is made up of tiny particles called atoms, The atoms of each element are identical, Chemical compounds form when different atoms of elements combine, Chemical reactions involve reorganization of the atoms

JJ Thompson

credited with the charge of the electron using his cathode ray tube experiment

Milikan

Credited with finding the mass of an electron to be 9.11×10^-31 kg, using his oil drop experiment

Rutherford

credited with finding that the atom has a small, solid, positively charged center called a nucleus

Cathode ray tube experiment

he used a vacuume sealed glass tube with the ends attatched to a positive anode and a negative cathode, he shot electrons through the tube from the cathode. He put a positively charged plate at one end of the tube and a negative plate at the other end, the light beam made by the electrons bent upward towards the positive end, making the electrons have to be negative.

Oil Drop Experiment

Milikan sprayed oil through an atomizer, the droplets then fell through a pinhole into a chamber with two metal plates one positive the other negative, He then put x-rays through the field making the oil droplets catch free electrons and become negatively charged, from there he could control the voltage of the metal plates and adjust how the droplets moved, he measured how fast the oil fell to calculate its mass.

gold foil experiment

shot a beam of positive alpha particles through a thin peice of gold foil, thought that maybe a couple alpha particles might stray a little bit away but most would go right through. Most did go right through but some hit something and strayed farther than expected (they hit the nucleus)

current view of an atom

A tiny nucleus and electrons moving around it

what is a nucleus made up of

protons and neutrons

What is the Atomic number of an atom

the number of protons in the atom

what is an isotope?

Atoms with the same number of protons, but different number of neutrons in the nucleus

what is the mass number

the total number of protons and neutrons

what are the three isotopes of hydrogen?

protium (1 proton, 0 neutrons), Deuterium ( 1 proton, 1 neutron), Tritium ( 2 protons, 1 neutron)

what are groups/ families on the periodic table

Vertical columns

what are periods on the periodic table

Horizontal rows

What is Electron Affinity

the amount of energy released when an isolated, neutral gaseous atom gains an electron to form a negative ion

What is Ionization energy

the minimum amount of energy needed to remove an electron from a gaseous atom or ion

what is Coulombic attraction

the pulling force between particles with opposite electrical charges

What is Atomic radius

the total distance from an atom's central nucleus to the outer boundary of its surrounding electron shell

Metals

Cations, conducts electricity, malliable, ductile

Non metals

Anions, mostly gases and liquids

Semi metals

have properties of both metals and nonmetals, ex. silicone

what is a chemical bond

Forces that hold atoms together in a compound

Covalent bond

results from atoms sharing electrons or between nonmetals, called molecules

Ionic bonds

results when there is an attraction between oppositely charged atoms (ions) or between a metal and a nonmetal

why do cations occur

because an electron is lost

why do anions occur

because an electron is gained

why are atoms charged

because they are made up of naturally charged particles ( protons, electrons, & neutrons)

What is an acid

Any ironic compound that has hydrogen in the beginning of it

Stoichiometry

Tells the quantities of materials consumed and produced in chemical reactions

Atomic masses

Even though each atom of an element could be different, scientists consider each element to be of one weight, the average weight. Allows for weighing of elements instead of counting the atoms.

The mole

Technically defined as the number equal to the number of carbon atoms in exactly 12 grams of pure ¹²C

Molar Mass

Defined as the mass in grams of one mole of a compound.

how do you find molar mass

Add up the weights of each atom that makes up the compound.

1 mol = ?

6.022 × 10²³

Percent Composition

Tells the percentage by mass of each element found in a compound

Empirical Formula

Simplest whole number ratio of elements for a compound

Chemical reactions

Involves a reorganization of atoms in one or more substances.

Reactants

tells which chemical begin the reaction. 

products

tells which chemicals are formed in the reaction.

What does a balanced equation do?

tells us the mole-mole ratio

Tera

T, 10^12

Giga

G, 10^9

Mega

M, 10^6

Kilo

k, 10³

Hecto

h, 10²

Deca

da, 10^1

deci

d, 10^-1

Centi

c, 10^-2

milli

m, 10^-3

micro

µ,10^-6

nano

n, 10^-9

pico

p, 10^-12

Ammonium

NH4 +1

Acetate

C2H3O2 1-

Bicarbonate

HCO3 1-

Chlorate

ClO3 1-

Chlorite

ClO2 1-

Cyanide

CN 1-

Hydroxide

OH 1-

Nitrate

NO3 1-

Nitrite

NO2 1-