INTRO CONCEPTS
Have you read chapters 1&2?
Do you know:
-what an SI unit is?
- the difference between fundamental and derived units? -examples of each?
- the difference between intensive and extens ive properties? -examples of each?
- the difference between chemical,physical,and nuclear changes? -examp les of each?- the difference between chemical and physical properties? -examples of each?
- how a period is different from a group or family in the periodic table?
-where are the halogens, transition metals, lanthanides,actinides,alkali metals,alkaline earthmeta ls,no b le gas e s,c halc o gens,meta llo id s,metals,and no nmeta ls?
-which elements are diatomic?
-which elements are liquids,which are solids,and which are gases at room temperature?-why some elements have symbols using letters different than the first two letter of the nameof the element?
-which elements are radioactive?
- how kinetic energy is different from potential energy?
- how heat is different from temp erature?
- how to distinguish between an element,a compound,a true solution,a colloid,and asusp ens ion?
-what are the basic structural units a for the above substances (elements,compounds,etc.)-why three different temperature scales exist&what the s ignificance is of each?
-what a calorie and what a joule is?
- how specific heat differs from heat content?
-what the three common states (phases)of matter are?
- how plasma fits in with the other states?
-what is the definition of matter?
- how mass differs from weight?
-what are the various types of energy?
-what the Law of Conservation of Mass states?
-what the Law of Definite Composition states?
-what equation relates mas s to energy?
-what the characteristics are of an exothermic reaction vs.an endothermic reaction?-what the d ifferenc e is b etween homogeneous and heterogeneous mixtures?
-where alloys fit in the classification scheme of matter?
-what luster,ductility,malleability, tens ile strength,density,heat conductiv ity,and electricalconductivity have to do with metals?
- how metals differ from nonmetals?
DO YOU KNOW ALL OF THE TERMS ON ALL OF THE HANDOUTS ON THISTOPIC???
Definitions of Physcial,Chemical,&Nuclear Changes
I.Physical Changes:
A. sublimation-conversion o f a solid directly into the gaseous state(no liquid formed)
B.vaporization -conversion of a liquid into the gaseous state
C.condensation -conversion of a gas into the liquid state
D. fusion -combination of two solids; soldering metal would be an example.
E.molecular dispersion -diffusion of gaseous particles; spreading particles from an area of highconcentration to one of low concentration
F. solidification -conversion of a liquid into the solid state
G.dissolution-dissolving;dispersion of a solute through a solvent to form a solution
H. temperature change - transfer of heat;kinetic energy change
I.deposition -opposite o f sublimation;conversion o f a gas directly into the solid state
J.pulverization - reducing solid size;grinding
K. liquefaction -melting;conversion o f a solid to the liquid state
II.C he mical C ha nge s:
A.po lymerization - formation o f a po lymer(chain)fro m mono mers or dimers
B.oxidation reduction(redox reaction) - transfer of electrons from one substance to another
-oxidation- loss of electrons; - reduction-gain of electrons
C.decomposition -chemical breakdown of a more complex substance into simpler forms
D.neutralization - special type of metathesis or double replacement reaction in which an acid and a baseare combined to form water,as a well as a salt by-product
E.photosynthesis - synthesis reaction in which carbon dioxide and water,using radiant energy, formsimple sugars, like glucose.Oxygen gas is released as a by-product.
F.digestion -breakdown of food substances into simpler form by chemical&mechanical means.
G.bacterial action -usually anaerob ic-breakdown o f organic matter
H.combustion - reaction of a substance with oxygen; highly exothermic in nature
I. respiration -appears to be the opposite process of photosynthesis in terms of the overal equation form
-aerobic breakdown o f simp le sugars,yielding CO 2 and H2O
J.electrolysis -decomposition of compounds using direct current (D.C. -not A.C.)
K.fermentation -anaerob ic decomposition o f carbohydrates
L.metathesis -also known as double replacement or double displacement -exchange of cations andanions when two compounds are mixed
M.vulcanization-addition o f sulfur to natural rubber- strengthens the rubber&adds resilienceIII.Nucle ar C ha nge s:
A. fission- splitting of a target nuclide using a bombarding particle;usually produces two or more nearly-equal smaller nuclides as well as some radioactive subatomic particles (radiation).
B. fusion-jo ining o f two lighter nuclides to form a larger,heavier nuclide.
-common example:reactions of the stars,producing light and heat.
C.radioactive decay- spontaneous breakdown of an unstable nuclide;usually produces a nuclide ofs lightly smaller ato mic number(Z number).Radioactive p artic le s are also emitted.
D. transmutation-artific ially creating new nuc lides by bombarding one nuc lide with another nuc lide(usually a small nuclide with a very small Z#).
Groups(families)of the Periodic Table to know:
I-A Alkali metals (from Arab ic“arising from ash”)
II-A Alkaline earth metals
V-A “pnictides”-from the Greek word meaning choking suffocation
VI-A Chalcogens -“arising from ore”
VII-A Halogens -“salt-formers”
Group B metals - trans ition metalsgroup along the stairsteps -metallo ids or semimetals (does not include B or Al)VIII-B Iron family
IB -c o inage me talsbottom two rows of iron family-#44,45,46&76,77,78known as the noble metals,due to lack of reactivity
Group VIII noble gases or inert gasesbottom rows -called the“inner transition metals
#57-71 -also known as the lanthanides or“rare earths”
#89- 103-also known as the actinides
Elements past#92- transuranium elements
Elements past#83 -are all radioactive
Elements of note:
I.Elements o f the universe
Most abundant element–H
Second most abundant–He
These two elements comprise most of the mass of the universe because most of the universe’s mass isconcentrated in the stars. These stars are undergoing fusion reactions.
II.Elements of the earth’s biosphere(crust,oceans,and atmosphere)oxygen-49.5%s ilico n-25.7%a luminum@7.5%
#4–Fe@4.7%; #5–Ca@3.4%;#6–Na@2.6; #7–K@2.4%;
#8–Mg@1.9%; #9–H@0.87%; #10–Ti@0.58%
These 10 elements account for 99.2%of the biosphere(by mass).
If only the earth was considered, iron&nickel would have much higher percentages because we believethe core to be made mainly of these two metals.
Four elements actually have ferromagnetic properties.
Obviously, there’s Fe,but Co,Ni,and Gd are also magnetic.
Since 75%of the earth’s surface is covered in water–H2O–a large part of that is oxygen. In addition,2/3 ofthe dry surface is desert–sand or SiO2–thus the reasonthat oxygen is#1.
(The desert composition is the reason that silicon is#2.)
The most abundant of the metals is aluminum, since a large portion of the earth’s crust contains bauxite–the mineral form ofAl2O3.
III. Elements in living organisms
Carbon–key element for living organisms
Hydro gen,O xygen,N itro gen
C,H,&O are found in carbohydrates as well as lipids (fats&oils)
In addition to these three,N is a key component ofproteins
Sulfur–important in membrane s&bonding in skin,hair,etc.
Phosphorus–needed for bones as well as for nucleic acids
Calcium–needed for bones
Nucleic acids–DNA and RNA
DNA–5-carbon sugar(deoxyribo se),phosphate group s,and nitrogen containing bases
(adenine,guanine, thymine,and c ytos ine)
RNA–same as DNA except that it uses ribose,and uracil is substituted for thymine
Catenation–property exhibited by carbon–can form long chains of carbon atoms bondedto each other
IV. Most malleable metal is gold–can be pounded to 4 millionth of an inch thick.
V. Electrical conductivity–best–Ag;#2–Cu;#3–Au; #4-Al
Classification of Matte r
Matter
Pure Substance Mixture
(Homo geneous) (Homo geneous or Hetero geneous)
True Element Compound Solution Colloid Suspension
[covalent molecules or ionic compounds]. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . . .. . .. .
Phase:region with a similar set ofproperties
Interface: site where two phases meet
Solutions:make sure it is known that mixtures can occur for all states
Solvent/So lute/So lutio n
Solute- substance that is dissolved(usually the smaller amount)
Solvent- substance that does the dissolving
Collo ids:disp ersed&dispers ing mediums - s imilar to so lute&so lvent in so lutions
Tyndall effect: scattering of light in colloids by the dispersed medium
Notes on Nuclear Chemistry
Types of radioactive particles–symbols,degree ofpenetrability
Alpha()–similar to the nucleus of a helium atom
Beta()–similar to a high-speed e lectrongamma()–a high-energyphoton–has no charge or massne utro n,pro to npositron–piece of antimatter–similar to a positively-charged electrondeutero n, tr ito n
Atomic numb er(Z#)vs.Mass number(A#)
1. identificationofelement 2.percentabundance ofisotopes
3.difference between isotopes and nuclides 4.nucleons
Types of nuclear reactions
1.fission 2.fusion 3. spontaneous decay 4. transmutation
1. In a fission reaction,a bombarding particle splits a nuclide into two nearly equal nuclides.O ften,one or more expelled particles are also emitted.These reactions are highly exothermic.n+U-235Te-137 +Zr-97 + 2 nor n+U-235Ba-142 +Kr-91 + 3 n
For a fission reaction to be sustained, there must be a“critical mass”present–enough of theradioactive material present so that a chain reaction takes place.
2. In a fusion reaction, light nuclides are thrown together at extreme ly high speeds–high enough tocause them to“fuse”together.
Without a doubt, the most common fusion reactors are the stars.
H + H-2 He-3
He-3 +He-3 He-4 + 2 H
He-3 + H He-4 + +
3. Spontaneous decay occurs without an outside influence. Because the nuclide is not stable, it willemit a particle on its own(presumably to try to achieve a balance of nuetrons&protons)
4. The first transmutation reaction was performed by Rutherford in 1919.
He converted N-14 into O-17 by bombarding the nitrogen with an alpha particle,and a proton wasthe expelled particle.
Half-life
- define half-life
- ln(Ao/At)=k t
- when Ao=2A, then ln(Ao/At)=ln(2)=0.693 and t=t½so 0.693=k t1/2
*Mass defect problems–conversion of mass into energy–binding energy forces
*Nuclear reactors–pros&cons
*Radioactive dating
X. Types ofparticle accelerators
XI. Effects of radon exposure
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