History of geochemical study. correct answers Geochemistry is the marriage of the fields of study: geology and chemistry. Roots take place in the origin of Chemistry as a discipline.
Conceptual stage of geochemistry correct answers Aristotle 350 BC- four components earth, air, water, and fire.
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history of geochemical study correct answers geochemistry is the marriage of the fields of study geology and chemistry roots take place in the origin of chemistry as a discipline
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Geochemistry Exam 1 (correct answers)
History of geochemical study. correct answers Geochemistry is the marriage of the
fields of study: geology and chemistry. Roots take place in the origin of Chemistry as a
discipline.
Conceptual stage of geochemistry correct answers Aristotle 350 BC- four components
earth, air, water, and fire.
Alchemists attempted to use the "spirit of Earth" energy and materials to convert
materials into silver and gold.
Classical period of geochemistry correct answers Boyle 1660 discovers the element
hydrogen.
James Hutton (father of modern geology) publishes his book "Theory of the Earth" in
1795.
"geochemistry" as a term was first used by the Swiss chemist Schonbein in 1838.
Analytical period of geochemistry (1900 to present). correct answers Meteorites and
Earth materials analyzed and classified according to composition. Terminology of rock
and water groups developed.
F.W. Clark correct answers Published Data of Geochemistry (1908; 5th edition in 1924).
He published extensive tables of chemical data on rocks, water, and atmosphere. Each
rock is chemical system which changes can be brought about. Changes imply that a
disturbance of the system has occurred.
V.M. Goldschmidt correct answers Norwegian father of geochemistry (work in early
1930's). Quantitative determination of distribution of elements in the Earth systems (as
F.W. Clark had done). Describe laws (mechanistic processes) which control the
distribution of elements in Earth. System interactions - e.g. minerals, water, biota. He
determined relationships between the ionic radii and charge for the substitution of
different elements in minerals.
Modernt Advancements in "Quantitative Chemical Analysis" correct answers Improved
analytical capabilities, ppm-ppm analyses are routine, ppt analysis now commercially
available, laser beams 4 micron spot size, etc. Cleanliness and appropriate standards
now limit data quality. Synchrotron radiation sources, using brilliant x- ray sources to
study nanometer sized clusters or atoms and bonding characteristics at reacting
surfaces. Modern geochemistry combines empirical study with model or philosophical
analysis. Employment of remotely operated analytical instruments in extraterrestrial
settings, spectral analysis from remote settings.
Purpose/ Usefulness of Science correct answers 1) Investigating natural phenomena.
2) Developing knowledge base (recorded in publications).
3) Developing "useful" technologies (along with the practice of Engineering).
,The scientific method deals with... correct answers Observations, Hypothesis (driven by
human curiosity), Testing - data collection, analysis, and evolution- revised hypothesis if
necessary, a widely accepted hypothesis = theory.
Observations correct answers Human curiosity and intuition leads from observation to
hypothesis of "why". Intuition is based largely on our everyday experience, which is very
limited compared to the range of phenomena that science attempts to understand. As a
result our intuition often deceives us. Sensory overload often stymies human curiosity,
derailing the process.
Hypothesis correct answers A plausible explanation that attempts to answer a question
about your observations. A hypothesis has not been rigorously tested, nor is it generally
accepted by a large audience.
Testing of the hypothesis- how can we tell if our hypothesis is correct/ accurate? correct
answers Designed experiments, data collection, scientific study, computer models.
Data verification correct answers To replicate data/ observation independently- by a
separate observer, team of observers, or laboratory, and preferably by a different
technique or instrument to assure that the data is accurate.
Hypothesis acceptance, modification, rejection depending on test results correct
answers If hypothesis is correct, then accepted and the phenomenon is considered to
be well- understood. If the hypothesis prediction is incorrect, then is discarded or
modified.
Truths about the scientific method correct answers Scientific understanding processes
through an endless cycle of observation, theory, and prediction. Hypotheses can
achieve "acceptance", but can never be proven correct, because we can never be sure
that they will not fail future tests. Engineering practice takes generally accepted
hypotheses and applies them to create or improve useful products' practices for human
kind.
Theory correct answers A well tested and generally accepted hypothesis.
Confusion in the scientific method arises because... correct answers 1) Poor
understanding of the terms hypothesis, theory, and fact by scientists, politicians, funding
agencies, and public (a problem with our educational system).
2) Need to generate impression of an absolute truth for issues that will enhance
opportunities for political gains by politicians, and for scientists and engineers to secure
research funding (a business practice).
3) Belief that the public will not accept a "theory" and thus not take prudent action (a
political process, propaganda).
4) Industry needs to market and sell new products (advertisement).
, Sub- Atomic Particles correct answers Major components: nucleus (protons + neutrons)
plus orbital electrons arranged in shell or cloud like structure around nucleus.
Electron correct answers Symbol: (e-)
Atomic Mass: 1/1840
Charge: -
What defines the element? correct answers Number of protons defines the element. All
oxygen atoms have 8 protons so the atomic number of oxygen is 8 on the periodic
table.
What defines the atomic mass? correct answers Number of protons + neutrons is the
atomic mass. Oxygen may have 8, 9, or 10 neutrons producing isotopes of O- 16, O-17,
or O-18, respectively. Atomic mass strongly influences physical behavior of atoms:
evaporation or condensation of H2O.
What influences chemical reactions- bonding? correct answers The number of
electrons, especially in outer shell.
Atomic Number correct answers The number of protons contained within an atom.
Thus, the number of protons determines what the element is. "Z- number"
Atomic Mass correct answers The mass of a given number of atoms- defined for one
mole of a substance. (6.022 x 10²³ molecules- avagadro's number) given in grams per
mole. relative to carbon- assigned a mass of 12.0000. Defined by the number of P+N.
What causes an atomic mass to be greater than what we would expect? correct
answers 1) Electrons and other subatomic particles contribute to the mass.
2) Isotope C-12 makes up 98.90% of all carbon, the heavier isotope C- 13 makes up
1.10% radioactive C-14 also makes up a small percent.
Isotope correct answers Given atoms of the same element (same # of protons) that
have a different mass due to varying numbers of neutrons. Ex) C-12= 6 protons + 6
neutrons. C-13= 6 protons + 7 neutrons.
Number superscripted to the upper left of an element. correct answers Represents the #
of protons + the # of neutrons. This is the isotopic mass.
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