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CHEM-C 101: EXAM ONE
Hypothesis |
first time a theory is postulated
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Theory
|
attempt to explain why a law exists
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Law |
summary of data collected in experiments
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vaporization
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liquid to gas
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condensation
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gas to liquid
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homogeneous
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uniform throughout (solution)
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precision
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need 2 or more measurements and it is how close the numbers are compared to the other ones in a group
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accuracy
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how close you are to the actual measurement
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intensive property
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does not depend on the amount of material
ex. density
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extensive
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does depend on the amount of material
ex. mass, volume
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rounding with 5's followed by 0's: even
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if it is a five followed by zeros or a 5, and the last number to be retained is even, drop the 5s and the zeros after
ex. 1.450000 to 1.4
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rounding with 5s followed by 0s: odd
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if the last digit to be retained is followed by 5s and 0s or just a 5, add one to the odd number and drop the 5 and 0s
ex. 1.567500000 to 1.5678
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atomic number
|
number of protons in the nucleus. never changes. atoms identity
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mass number
|
number of protons plus neutrons
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isotope
|
same atom, diff number of neutrons
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atomic mass
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1 amu= 1/12 of the mass of carbon 12
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specific heat
|
amount of heat energy (cal or J) needed to warm one gram of a substance by 1 degree celcius
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specific heat formula
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q= change in temp x sh x mass
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how many calories= 1 C
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1000 |
density formula
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d= m/v
g/ml
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what is density
|
measure of compactness of matter
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matter |
anything that occupies space or has mass
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element |
basic building block of matter
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model |
some kind of physical picture or math expression of a theory
|
F to C equation
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F= 9/5C + 32
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K to C equation
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K= C + 273.15
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law of conservation of matter
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mass of products= mass of reactants
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law of constant composition
|
multiple samples of any pure chemical compound always contain the same % by mass of each element making up the compound
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size trend in periodic table
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as we go down a group we get larger (more rows of electrons), as we go across a row we get smaller (more proton pull)
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ionization energy
|
amount of energy required to move and electron from an electrically neutral atom
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ionization energy trend in periodic table
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as we go down groups energy is less (v. electron is farther away from nucleus) as we go across periods it gets more (more pull from nucleus from protons)
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the bigger the atomic number... the _ the size and _ the pull
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smaller the size and stronger
|
cation |
positively charged atom
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anion |
negatively charged atom
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Rutherford is famous for...
|
his gold/alpha particle experiment and discovering a nucleus
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Thompson model of atom
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plum pudding model
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law of Mendeleev
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properties of the elements recur in regular cycles (periodically) when the elements are arranged in order of increasing atomic mass
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representativeand main group elements
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which chem was based IA-VIIIA
|
noble gases
|
6 in VIIIA
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metals |
shiny solids, bendable, malleable, conduct heat and electricy
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nonmetals |
brittle, do not conduct electricity and heat well, they are insulators. in between gases and metalloids, and H
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metalloids
|
7 exist. properties are in between metal and nonmetal. they are semiconductors
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chemical property
|
ways a pure substance behaves when it is combined with other pure substances
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