Explain this statement in your own words and give an example: The properties of the substances around us depend on the structure of the particles that compose them.
1. A substance's properties depend on their structure.
H20 is needed for life but change the 0 to 02 and you have peroxide.
Explain the main goal of chemistry.
To study a particle's structure and properties.
What are two different ways to classify matter.
Matter can be classified by state or its composition.
How do solids, liquids, and gases differ.
Solids are highly attracted to each other and tend to stay in a fixed position. Liquids are slightly less attracted to each other which cause them to have fixed volume but not a fixed shape. Gases have a very weak attraction and have large spaces between the particles, making them compressible.
Explain the difference between a pure substance and a mixture based on the composite particles of each.
Pure substances are composed of one type of atom or have fixed composition versus a mixture which can have a wide composition.
Explain the difference between an element and a compound.
An element contains only one type of atom. A compound contains two or more types of atoms in a fixed composition.
Explain the difference between a homogeneous and heterogeneous mixture.
Homo. Mixtures have the same composition throughout, while hetero. Mixtures do not.
Describe the scientific approach to knowledge How does it differ from other approaches.
Scientific knowledge is empirical.
Explain the difference between a hypothesis, a law, and a theory.
hypothesis is a tentative interpretation or explanation of observations.
Laws, hypotheses and theories all give rise to predictions that can be tested by experiments, carefully controlled procedures designed to produce new observations.
Scientific theory explains why nature does what it does
What observations did Antoine Lavoisier make? What law did he formulate?
Law of conservation of mass by observing items burning in a closed container.
What theory did John Dalton formulate?
Atomic Theory.
What is wrong with the expression " that is just a theory" if the speaker is referring to the scientific theory.
Theories are based on numerous observations and experiments.
Summarize the history of the atomic idea. How was Dalton able to convince others to accept an idea that had been controversial for 2000 years,
Dalton was able to convince others of his theory because it explained more than one law.
State and explain the law of conservation of mass.
Matter is not created or destroyed in a chemical r x n.
state and explain the law of definite proportions.
A sample of a compound; regardless of their sources; have the same proportions of their component elements.
state and explain the law of multiple proportions. How is the law of multiple proportions different from the law of definite proportions.
When 2 elements form different compounds the ratio of element B can be expressed as a small whole number.
What are the main ideas in Dalton's atomic theory. How do they help explain the laws of conservation of mass, of constant composition, and definite proportions.
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How and by whom was the electron discovered. what basic properties of the electron were reported with its discovery.
JJ Thomson by cathode ray tube determined that electrons have negative charge.
Explain Millikan's oil drop experiment and how it led to the measurement of the electron's charge. whyis the magnitude of the charge of the electron so important.
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Describe the plum pudding model of the atom?
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Describe Rutherford's gold foil experiment. How did the experiment prove that the plum pudding model of the atom was wrong?
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Describe Rutherford's nuclear model of the atom. What was revolutionary about his model??
The atom had never been described this way.
If matter is mostly empty space, as suggested by Rutherford, then why does it appear so solid.
Because the nucleus contains 99% of the mass of an atom.
List three subatomic particles that compose atoms and give the basic properties (mass and charge) of each.
Mass Charge
Proton 1.0727 +1
Neutron 1.00866 0
Electron 0.00055 -1
What defines an element?
Number of protons
Explain the difference between Z ( the atomic number) and A ( the mass number)
Z is the number of protons. A is the number of protons plus neutrons.
Where do elements get their names?
Based on English or Latin names.
What are isotopes? what is percent natural abundance of isotopes?
Atoms of the same element with a different number of neutrons.
The relative amount of naturally occurring isotopes.
Describe the two different notations used to specify isotopes and give an example of each.
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What is an ion? A cation? An anion?
Charged particle, positive ion, negative ion.
What is atomic mass? How is it calculated?
Weighted average of the naturally occurring isotopes determined through the mass spectrometer.
Explain how a mass spectrometer works. What kind of information can be determined from a mass spectrum.
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