Chem 1: Ch 5-9 UMT Dwyer Flashcards
Midterm I
Petrochemical
substance that is made from petroleum or other related substances such as coal or natural gas
Petroleum
a thick, flammable, yellow to black substance found in selected locations on earth, usualy in underground resevoirs; central to modern life in industrialized nations
water
clear, colorless, tasteless substance found almost everywhere on earth; essential to life support
petrochemical era
the period of time in which petrochemicals are used to manufacture products that are central to all aspects of life. generally agreed to have started inthe 1940s and is accelerating and continuing today
3 phases of matter
s, l, g
solid
constant shape and volume; vibration in a fixed position
liquid
variable shape (bottom of a container) and constant volume; touch one another & move around each other
gas
variable shape and volume (same as closed container); move independently, very widely spread
pure substance
one kind of matter, distinct and unue physical and chemical properties
mixture
sample of matter composed of 2 or more chemicals/substances; properties depend on relative amounts of parts
eg gin/water
element
a pure substance that cannot be decomposed into other pure substances by ordinary chemical means
compound
a pure substance that can be broken down into 2 or more pure substances by a chemical change.
Do NOT confuse element/compound with pure/mixture eg water is a pure compound that can be chemically separated into pure elemnts
physical properties
measurable and detecable by senses; eg water boils at 100*C
freezing point, boiling pt, density, color
physical change
new form of same substance
chemical properties
list of chemical changes possible; eg water reacts with sodium to form hydrogen, sodium ions, and hydroxide iions
chemcial change
old substance destroyed, new substance formed (eg hindenburg disaster)
homogenous
uniform appearance and composition throughout
heterogeneous
visibly different phases and/or different composition in a sample of matter
distillation
process of separating the components of a mixture by heating the liquid and collecting the gaseous components that sepearate formt he remainder of the liquid
separation of mix based on differences in volatility, speed of evaporation
element with lower boiling point evaporates first
3 major substances extracted from earth
petroleum, coal, natural gas
Pure substances that are compounds
water, sugar, baking soda, aspirin
pure elemental substances
gold, copper wire, lead fishing sinks
fractional distillation
The vapor enters the bottom fo the column and rises through the column, with the substances with the higher boiling points condensing back to the liquid state nearer the bottom of the columna and the lower-boiling liquids condensing higher in the column
cracking
less valuable fractions are subjected to a process called cracking- where the fraction is transformed, or cracked into gasoline
Macroscopic appearance… bubbles
the terms homogeneous and heterogeneous refer to the macroscopic appearance of a sample. a container fileld with ice and liquid water is hetergeneous in appearance but is also pure, as long as in both phases the water is pure
electrical charge
a property of matter that causes it to experienc a force when near other electrically chaged matter
2 types of charged matter
- attracted to the other type
2. same type repels the same type
Ben Franklin
proposed the hypothesis that the two types of charged matter resulted from an excess or deficiency of a single kind fo charge
Alessandro Volta
Italian Scientist- invented the first battery “voltaic pile” after learning that he itneraciton of brass and steel and a solution could cause a muscular contraction in a frog’s leg
Nicholson & Carlisle
used the current generated by a voltaic pile to decompose liquid water into hydrogetn and oxygen, finding that the volume of hydrogen produced was twice that of oxygen
Nicholson & Carlisle’s discovery led to…
Law of Combining Volumes
Law of Combining Volumes
the volume ratios in which gases react are always a ratio of small, whole numbers
Avogadro’s Hypothesis
explains the Law of Combining Volumes by proposing that equal volumes of gases contain equal numbers of molecules
led to distinguishing btwn monoatomic and diatomic elements based on the nature of the combining volumes
Monoatomic
Adjective
Consisting of one atom.
Monovalent.
Diatomic
Adjective
Consisting of two atoms.
“plum pudding” model
By 1911 the components of the atom had been discovered. The atom consisted of subatomic particles called protons and electrons. However, it was not clear how these protons and electrons were arranged within the atom. J.J. Thomson suggested the”plum pudding” model. In this model the electrons and protons are uniformly mixed throughout the atom:
Rutherford “gold foil” experiment
Rutherford tested Thomson’s hypothesis by devising his “gold foil” experiment. Rutherford reasoned that if Thomson’s model was correct then the mass of the atom was spread out throughout the atom. Then, if he shot high velocity alpha particles (helium nuclei) at an atom then there would be very little to deflect the alpha particles. He decided to test this with a thin film of gold atoms. As expected, most alpha particles went right through the gold foil but to his amazement a few alpha particles rebounded almost directly backwards.
These deflections were not consistent with Thomson’s model. Rutherford was forced to discard the Plum Pudding model and reasoned that the only way the alpha particles could be deflected backwards was if most of the mass in an atom was concentrated in a nucleus. He thus developed the planetary model of the atom which put all the protons in the nucleus and the electrons orbited around the nucleus like planets around the sun.
Rutherford “gold foil” experiment
- discovered the proton via further experiments with alpha particles
What are the products when Nitrogen is bombarded with alpha particles?
protons are one product of the reaction
Oxygen
Who discovered the neutron?
many contributed, but it was Chadwick who ultimately conducted the highest quality experiments and interpreted the results correctly
What are the products when Berryllium is bombarded with alpha particles?
A particle with no charge and a mass similar to a proton
carbo
Electron
e or e- negative charge mass= 9.109 x 10%-28g 0.000549 u ~0 discovered in 1897 by Thomson
Proton
p or p+ positive charge mass= 1.673 x 10^-24 1.00728 u ~1 discovered in 1919 by Rutherford
Neutron
n or n0 zero charge mass= 1.675 x 10^-24 1.00867 u ~1 discovered in 1932 by Chadwick