Wednesday September 30, 2009

The Schrondinger Wave Equation

• Electrons do not travel around the nucleus in neat orbits, as Bohr had postulated.
• Instead, they exist in certain regions called orbitals.
• An orbital is a three-dimensional region around the nucleus that indicates the probably location of an electron.

Remember! Dr. B said that she did NOT like the use of the word orbital. Do not think of them as neat train tracks but as a volume.

Atomic orbitals and Quantum numbers

• Quantum numbers specify the proterties of atomic orbitals and the properties of electrons in orbitals.
• The principle quantum number, symbolized by n, indicates the main energy level occupied by the electron.
• The angular momentum quantum number, symbolized by a lower-case L (she likes it in cursive), indicates the shape of the orbital.
• The magnetic quantum number, symbolized by m, indicates the orientation of an orbital around the nucleus.
• The spin quantum number (s) has only two possible values, +1/2 or -1/2, which indicates the two fundamental spin states of an electron in an orbital.

Here is a chart she put up on the board which helps clarify the meaning of this.


Principal Quantum Number
Energy n= 1,2,3,...
Angular l= 0,1,2...n-1
Magnetic m= -l...0...+l
Spin s= +1/2, -1/2

Here are some Sample problems we did in Class illustrating this.

N=1 then
l=0 then
m=0 then
s=+1/2,-1/2
The total number of electrons is 2 (2e-)
This is actually the first row in the Periodic Table!.... hooray...?

Here is another.
N=2 then
l=0 or 1 then
m=0
s=+1/2,-1/2
Thus we have 2e- + 6e- which = 8e-.
If you are still not quite sure what happened, check out the diagrams in your books.
As a matter of fact, I will just give you a free one right here.


Quantum Numbers of the first 30 atomic orbitals

n l m orbital names Number of orbitals

1 0 0 1s 1
2 0 0 2s 1
2 1 -1,0,1 2p 3
3 0 0 3s 1
3 1 -1,0,1 3p 3
3 2 -2,-1,0,1,2 3d 5
4 0 0 4s 1
4 1 -1,0,1 4p 3
4 2 -2,-1,0,1,2 4d 5
4 3 -3,-2,-1,0,1,2,3 4f 7

The s,p,l,f,g are the sub-level orbitals

Electron Configurations

• The arrangement of electrons in an atom is known as the atom's electron configuration.
• The lowest-energy arrangement of the electrons for each element is called the element's ground-state electron, configuration.

Don't forget that Dr. B expects everyone to have finished the chapter by Thursday! (we are in section 3 right now)

Also in as a side note, Dr. B has not given a quiz for a while now, it would probably a good idea to start preparing for a very possible not to mention probable pop quiz.

Have a good day!

sorry i am late soccer ran long and my car pool had some more important errands...

we watched a movie but first jimbo talked about the cat in the box, colby got into trouble for being colby, and Dr. B. rejected me for prayer....again. Movie started at 12:30 and it was 72 degrees.

movie starts showing Fermilab, site of the once largest particle accelerator in the world. Physicists on the hunt for an amazing new particle, Higs Photon. (Lab also home to airplane club, tango club, and a rock band.)

Founder of the lab is Leon Ledermen, who explains how after the war science seemed to explode into a mass of discoveries. he says the immigration + science= american success

fermilab was stationed in texas and in 1977 they discovered the first of three quarks. the second twenty years later. (called a lab on the prarie because its surrounded by bison.) Quarks are connected by Gluon.

Accelerator works by first taking the electron out of say a hydrogen atom, leaving the proton; the proton is then shocked, making it speed up, while maintaining control via massive magnets. speed increases until BAM, SMASH, KABOOM, instant entertainment and occasionally some new information.

Higgs photon is so important because it is believed to be the cause of mass in all particles. mass is what defines our universe. can explain how our universe began.

expected discovery time=ten years from 2004.

sadly that wont happen because in 2006 the united states government made a budget cut canceling the program.

have a good night yall ill be in touch.

Chapter 4 Sections 1 and 2

Chapter 4 Section 1

The Development of a New Atomic Model

Bohr Model of Hydrogen Atom (continued)

• When an electron falls to a lower energy level, a photon is emitted, and the process is called emission.
• Energy must be added to an atom in order to move an electron from a lower energy level to a higher energy level. This process is called absorption.

Photon Emission and Absorption

• E-photon = E-2( orbit 2) subtracted by E-1 is the Absorption
• E-photon = E-1 - E-3 is the Emission

Chapter 4 Section 2

The Quantum Model of the Atom

Electron waves

• French scientist Lonis de Broglie suggested that electrons be considered waves confined to the space around an atomic nucleus.
• It followed that the electron waves could exist only at specific frequencies.
• According to the relationship E=hv, these frequencies corresponded to specific energies - the quantized energies of Bohr's orbits.
• Electrons, like light waves, can be bent, or diffracted.
• Diffraction refers to the bending of a wave as it passes by the edge of an object or through a small a opening.
• Electron beams, like waves, can interfere with each other.
• Interference occurs when waves overlap.

The Heisenberg Uncertainty Principle

• German physicist Werner Heisenberg proposed that any attempt to locate a specific electron with a photon knocks the electron off its course,
• The Heisenburg Uncertainty principle states that it is impossible to determine simultaneously both the position and velocity of an electron or any other particle.

The Schodinger Wave Equation

• In 1926, Austrian physicist Erwin Schodinger developed an equation that treated electrons in atoms as waves.
• Together with Heisenberg uncertainty principle, the Schodinger wave equation laid in the foundation for modern quantum theory.
• Quantum Theory describes mathematically the wave properties of electrons and other very small particles.

FRIDAY, SEPTEMBER 25, 2009

Today was a very fun day.

We learned how you can see the rainbow in the visible spectrum coming off of other light emitting objects. Using the tools Dr. Bautista gave us, we would look at the light and the different elements she put up on her desk. We saw that different elements emitted different colors of the rainbow in the spectrum. This is because when you send energy through the element tube, the electrons in the element get excited. When they get excited, they jump from one energy level to the other. That jump emitts light. Depending on how far and from what enery levels the electrons come from and go to, different colors of the rainbow will be seen.

We also played with fire which i thought was the coolest part of the whole day. When you spray borax on a big open flame and a candle, the flame changes from its original color to green. When you spray stronium nitrate into a big open flame and a candle, the flame changes from its original color to a bright red. We also saw that when you spray these two chemicals in an big open flame and a candle, the flame from the candle is a whole lot bigger than the one emitted by the big open flame.

This pretty much wraps up what we did in class on Friday.

P.S. Dr. Bautista always said to clean up after you do lab!!!

The Photo electric effect (cont'd)

• The particle description of light
• German physicist, Max Planck, purposed the following relationship between quantum of energy and the frequency of radiation
• E = h(v)
• E is the energy in joules
• v is the frequency of radiation emitted (not a v but the sign for new)
• h is the fundamental physical constant now known as Plank's constant, h=6.626 x 10^-34 [J x S]

• A photon is a particle of electromagnetic radiation having zero mass and carrying a quantum of energy
• The energy of a particular photon depends on the adiation
• E[of the photon]= h(v)

• The hydrogen atom line emission spectrum
• The lowest energy state of an atom is its ground state
• A state in which an atom has a higher potential energy than it has in its ground state is an excited state
• When investigators passed electric current through a vacuum tube containing hydrogen gas at low pressure, they observed the emission of a characteristic pink glow
• When a narrow beam of the emitted light was shined through a prism, it was separated into four specific colors of the visible spectrum
• 4 bands of light were part of what is known as hydrogen's line-emission spectrum
• Bohr Model of the Hydrogen Atom
• Niels Bohr purposed a hydrogen atom model that linked the atom's electron to photon emission
• According to the model, the electron can circle the nucleus only in allowed paths, or orbits
• The energy of the electron is higher when the electron is in orbits that are successively further from the nucleus

Homework tonight: comment on my awesome blog-age; and HW #10 pg 124, numbers 10-14

9/22/09

Dr. B hates the colts because of Peyton Manning. In the beginning of class, Dr. B passed back the lab and explained why one of us had points taken off and for what reasons. Most of the points taken off were from the average by mistaking the number of significant figures. She also answered any questions on the lab.

Properties of Light

The wave description of light

• Electromagnetic radiation is a form of energy that exhibits wave like behavior as it travels through space.
• Together, all the forms of electromagnetic radiation form te electromagnetic spectrum.
• Electromagnetic spectrum is arranged from long to short wavelength or from low to high frequency.
• As the wavelength decreases the frequency increases.
• Wavelength- the distance between corrosponding points on adjacent waves.
• Frequency- the number of waves that pass a given point in a specific time, usually one second.
• Frequency and wavelength are mathematically related to each other.

The equation for finding the speed of light is c: v(λ)

• In the equation, c is the speed of light(in m/s), λ, is the wavelength of the electromagnetic wave(in m), and v is the frequency of the electromagnetic wave(in s^-1)

One can measure an ocean wave's frequency ,v, by observing how often the water level rises and falls out.

The Photoelectric Effect

• The photoelectric effect refers to the emission of electrons form a metal when light shines on the metal.

The Particle Description of Light

• A quantum of energy is the minimum quantity of energy that can be lost or gained by an atom.

Photoelectric effect

Electromagnetic radiation strikes the surface of a metal, ejecting electrons from the metal and causing an electric current(This idea is used in a light bulb).

Conversion Answers

1. a. 3.7X10^-4 moles Pd
b.150 moles Fe
c. .040 moles Ta
d. 5.38X10^-5 moles Sb
e. 41.1 moles Ba
f. 3.51X10^-6 moles Mo
2. a. 52.10 g. Cr
b. 1.5X10^4 g. Al
c.8.23X10^-7 g. Ne
d. 300 g. Ti
e. 1.1 g. Xe
f. 2.28X10^5 g Li
3. a. 1.02X10 ^25 atoms Ge
b. 3.700X10^23 atoms Cu
c.1.82X10^24 atoms Sn
d. 1.2X10^30 atoms C
e. 1.1X10^14 atoms K
f. 1.943X10^14 atoms Zr
4. a.10.00 moles Co
b. .176 moles W
c.4.995X10^-5 moles Ag
d. 1.6X10^5 moles Pu
e. 7.66X10^-7 moles Rn
f. 1X10^-11 moles Ce.
5. a.2.5X10^-19 atoms Au
b.5.10X10^22 atoms Mo
c.4.96X10^20 atoms Am
d.3.011X10^26 atoms Ne
e. 2.03X10^18 atoms Bi
f. 9.4X10^16 atoms U

9-16-09: Atomic, Formula, and Molecular Weight Problem Set

Note: All atomic masses should be rounded to two decimal places before calculation, except Hydrogen (H), Helium (He), Lithium (Li), and Beryllium (Be), which should be rounded to three decimal places.

Part I. Answer the following questions. Use the periodic table to find atomic weights.

1. A silver atom weighs approximately 9 times as heavy as an atom of carbon-12. What is its atomic weight? Answer: ≈108 amu

2. Approximately how many times heavier than a carbon atom is an atom of neodymium (Nd)? Answer: 12.01 times heavier

3. Approximately how many nitrogen atoms would weigh the same as one atom of iron? Answer: ≈ 4 nitrogen atoms

4. Look at the atomic weight of chlorine in the periodic table. Suppose you are told that there are two isotopes of chlorine, namely chlorine-35 and chlorine-37. Which do you think is more abundant in nature, Cl-35 or Cl-37? Why? Answer: Cl-35, because the average atomic weight for chlorine is closer to 35 than 37.

5. There are three isotopes of hydrogen: H-1 (hydrogen), H-2 (deuterium), and H-3 (tritium). Look at the atomic weight of hydrogen on the periodic table. Which of the three isotopes do you think is most abundant in a sample of hydrogen. Answer: H-1 (Hydrogen)

Part II. Calculate the formula weight of each of the following compounds (answers in bold).

1. Na₂O₂ 77.98

2. PCl₅ 208.24

3. K₂SO₄ 174.26

4. Al(NO₃)₃ 213.01

5. C₁₂H₂₂O₁₁ 342.34

6. Ca₃(PO₄)₂ 310.18

7. K₂Cr₂O₇ 294.19

8. Pb(CH₃COO)₄ 443.376

9. Ba(CIO₄)₂ 336.227

10. NH₄HCO₃ 79.06

Homework Answers

17a. 6.94g of Li
b. 26.98g of Al
c. 40.1g of Ca
d 55.85 molar mass Fe
e. 12.01g C
f. 107.9g of Ag

18a. 1 mol of Ne
b. .5oomol of Mg
c.1.57x10^23 mol Pb
2.81x10^-13mol O

19. 39.95amu

20. 10.00amu

21a. 9.03x10^23 atoms of Na
b. 4.068x10^27
c. 1.50x10^30amu Si

22a. 9.5g F
b. 6.06g Mg
c. 2.7x10^-10g Cl
d. 1.12x10^-3g br
e. 7.6x10^-21g W
f. 3.0x10^-22Au

23a. 3.008x10^23 amu B
b. 1.5x1024 amu S
c. 2.31x10^22 amu k
d. 7.872x10^19 amu Pt
e. 3.0x10^11 amu Au

24a. 80g Al
b. 29.5g Li
c. 19.3g n
d. 1590g Au
e. 410g Cu
f. 8240000000g S
g. 3.5x10^-9g Hg

25. Particle Symbol Mass # Actual Mass Relative Charge
Electron e- -
Proton p 1 1.673 x 10^-24 g +
Neutron n 1 1.675 × 10^-24 g neutral

26a. It's 1/12 of a carbon-12 atom's mass
b. Mass compared with mass of carbon-12 atom

27a. Its dense core
b. Ernest Rutherford
c. Protons and neutrons

28a. 1.0005 mol Ca
b. 0.5002 mol Na
c. 0.100017 mol Ni
d. 4.68 mol S
e. .0474 mol Fe
f. 6.95x10^-5 mol Ag
g. 37.4 mol S
h. 8x10^-23 mol Ba

29. If two or more different compounds are composed of the same two elements, then the ratios of the masses of the second element combined with the mass of the first element is always a ratio of small whole numbers.
Ex. CO and CO2

30a. 144amu
b. 6 amu

31. Negativly charged particles in an atom that ornit the nucleus

Chemistry Notes for Mon., Sep.14

Relative Atomic Masses

• The standard used by scientists to compare unites of atomic mass is the carbon-12 atom, which has been arbitrarily assigned a mass of exactly 12 atomic mass units, or 12 amu.
• One atomic mass unit, or 1 amu, is exactly 1/12 the mass of a carbon-12 atom.
• The atomic mass of any atom is determined by comparing it with the mass of the carbon-12 atom.

Average Atomic Masses of Elements

• Average Atomic Mass is weighted average of the atomic masses of the naturally occurring isotopes of an element.

Calculated Average

• The average atomic mass of an element depends on both the mass and the relative abundance of each of the element's isotopes.

Copper consists of 69.15% copper-63, which has an atomic mass for 62.929601 amu, and 30.85% copper-65, which has an atomic mass of 64.9227794 amu.

The average atomic mass of copper can be calculated by multiplying the atomic mass of each isotope by its relative (abundance expressed in decimal form) and adding the results.

You must learn how to do this because it will be a test question.

(0.6915)*(62.929601)=43.5158909

(0.3085)*(64.927794)=20.03022445

43.5158909+20.03022445=63.54611535, which is rounded to 63.55 amu

Relative Mass to the Number of Atoms

The Mole

• The mole is the SI unit for the amount of substance.
• A mole(abbr. mol)is the amount of substance that contains as many particles as there are atoms in exactly 12g of carbon-12.

Avogardo's Number

• Avogardo's Number ~ 6.0221415*10^23 ~ is the number of particles in exactly 1 mole of a pure substance.

Molar Mass

• The mass of 2 mole of a pure substance is called the molar mass of that substance.
• Molar mass is usually written in units of g/mol.
• The molar mass of an element is numerically equal to the atomic mass of the element in atomic mass units.

Gram/Mole Conversions

• Chemist use molar mass as a conversion factor in chemical calculations.
• For example, the molar mass of helium is 4.00g the 1mol He.
• To find how many grams of helium there are in 2 moles of helium, multiply by the molar mass.

2.00 mol He * 4.00gHe/1 mol He = 8.00 g He

Conversions with Avogardo's Number Avogardo's Number can be used to find the number of atoms of an element from the amount in moles or to find the amount of an element in moles from the number of atoms.

• In these calculations, Avogardo's number is expressed in units of atoms per mole.

Amount of Element in moles*Molar Mass of Element/1 mol = Mass of Element in grams

Mass of Element in grams*1 mol/Molar Mass of Element= Amount of Element in moles

Mass of Elem. in grams*1 mol/Molar Mass of Elem.* 6.022 x 10^23 atoms/1 mol=Number of Atoms of Elem.

Number of Atoms of Elem.* 1 mol/6.022 x 10^23 atoms * Molar Mass of Elem.= Mass of Elem. in grams

Number of Atoms of Elem.* 1 mol/6.022 x 10^23 atoms = Amount of Elem. in Moles

Amount of Elem. in Moles* 6.022 x 10^23 atoms / 1 mol = Number of Atoms of Elem.

Example

• What's the mass in grams of 3.50 mol of the element Copper, CU?

(3.50 mol CU * 63.55 g CU)/ 1 mol CU = 222 g CU

9/11/2009

Oxygen atom on periodic table

8

O

15.9994

[He] 2s^2 2p^2

Isotopes

Isotopes are atoms of the same element that have different masses.

The Isotope of a particular element all have the same number of protons and electrons but different numbers of neutrons.

Most of the elements consist of mixtures of Isotopes .

Mass Number

Mass number is the total number of protons and neutrons that make up the nucleus of an isotope.

-The Atomic mass is a decimal

Designating Isotopes

Hyphen Notation: The mass number is written with a hyphen after the name of the element.

- Uranium – 235

Nuclear symbol: The superscript indicates the mass number and the subscript indicates the atomic number

- Mass Number Þ235 U

- Atomic NumberÞ92

The number of neutrons is found by subtracting the atomic number from the mass number.

- Mass number – Atomic number= Number of Neutrons

- 235 – 92 = 143 for U

Nuclide is a general term for a specific Isotope of and element.

9-9-09 The Atom

Discovery of the Atomic Nucleus

• 1911- Ernest Rutherford, Hans Geiger, and Ernest Marnden conducted the golden foil experiment.
• Discovered a very densely packed bundle of matter with a positive charge in the atom. Rutherford named it the nucleus

Composition of the Atomic Nucleus

• Made of protons and nuetrons
• Protons have a positive charge equal in magnitude to the chare of an electron
• Atoms/elements are electrically nuetral because they contain an equal number of protons and electrons
• Nuetrons have no charge
• Nuclei of atoms of different elements diifer in number of protons and nuetrons and therefore the amount of positive charges they posses.
• The amount of protons determines that atom's identity

Forces in the Nucleus

• When 2 protons are extremely close, there is a strong attraction between them. This attraction also exists between close neutrons or a proton and a nuetron that are close to each other.
• The forces that cause these attractions are nuclear forces.

The Sizes of Atoms

• radius-- distance from center of the nucleus to the outer portion of its electron cloud
• Atomic radii are expressed in picometers (pm).
• atomic number(Z)- the number of protons in each atom of an element

Pre Lab Stuff

Hey y'all. Having a good day? I guess not, since you're doing homework right now. Well you should get excited! We're doing a lab soon! YES!!!

POPCORN LAB- PROBABLY THURSDAY!
Pen. ALL pen! No PENCIL!


Popcorn packs come in little plastic packages. Take off the plastic, and mass the pack. Remember-

• this side up!
• Wait until 1 second between pops to stop popping

Clear the extra seconds off the microwave.
Mass at room temperature.
Open the bag a little.
Wait for it to completely cool ROOM temperature!
2 reasons for the kernels that don't pop

• not enough moisture

• hole in kernal
• http://www.rediff.com/getahead/2005/apr/19corn.htm
  

The Microwave was first used for popcorn. Excited the water molecule to boil, turns it to vapor, causes starch to expand. The starch, when cooled, turns to its sold form. We will be calculationg percent water/mositure in the popcorn.

(How Popcorn Works) http://dsc.discovery.com/videos/how-stuff-works-popcorn.html

Table 1
1. Mass of popcorn before popping
2. Mass of popcorn after popping (and cooling)
3. Mass of H2O in popcorn ( 1-2 )
4. % of H2O in popcorn (by mass) ( 3/1 * 100 )


Go to the white board (table 2) and write Group #, and # for data.

Table 2
Group #---Brand of Popcorn---% H2O by Mass
1
-
-
15


After everyone's finished:
1. Calculate Average
2. Calculate standard deviation (http://hubpages.com/hub/stddev)
3. Use your data for % error
4. Google % H2O in popcorn (http://en.wikipedia.org/wiki/Popcorn)

We will pick our own groups

PRE-LAB
Title of Lab

• write under the blue bar.

Purpose of Lab

• finding the percent of water by mass in popcorn.

Materials

• Popcorn Bag, Microwave, Balance Good Attitude

Procedure

• Bullets fine.
  
• Everyone's is different.
  
• Concise.
  
• Easy to follow
• Only lab notebook, pen, calculator, and good attitudes allowed at lab station

Data Tables

• Draw lines around- Use Rulers
• Give yourself Room.
• Double Spaced
• Error Correction- No white out/ Scribble. Draw one line through the incorrect measurement, then write the correct measurement underneath it.

Pre-Lab Questions

• What is the formula for standard deviation?
• Only the answer is needed
  

LAB
See information at Top^ DUH!

POST LAB

Calculations

• Do 'em well
• You can do them outside of class (She actually expects it)

Post Lab Questions

• Just answers needed
• Pg. 64-65
• 2nd one under Conclusions
• Both under extensions

Conclusion

• discusses mistakes made
• did you achieve goals?
• could any improvements be made in this lab?
• Minimum of 3 complete sentences
  

ENTIRE LAB DUE NEXT TUESDAY

Here are some great websites!

http://funnyjunk.com/movies/2219/Popcorn+In+Ultra+Slow+Motion/
http://www.youtube.com/watch?v=9N4ckFN96-k
(^ possibly the greatest video ever posted on this blog ^)

I love you guys. School's tough this year, but persevere.

9/4/09

We watched a movie today: KABOOM!

• Ground zero is a test range for the FBI to test high-powered explosives.
• Detenation of an explosive is the rapid rearrangement of atoms.
• Sidney Hawford - internationally known explosive engineer
• Things needed for an explosive: 1)means of ignition 2)fuel source 3) oxygen
• Roger Bacon - investigated gunpowder, made of saltpeter, sulphur, and charcoal; also found a wat to get better quality of saltpeter
• 1 million frames/second is required to catch the detenation of an explosive on film
• Alfred Nobel - invented the detenator; Nitroglycerin - extremely dangerous explosive used in dynamite; Dynamite - mixed nitroglycerin with inert absorbants; Blasting gel - same amount of explosiveness as nitroglycerin, but as safe as dynamite

September 3, 2009

Law of Conservation of Mass (picture on the right)



a) an atom of carbon and an atom of oxygen can combine chemically to form a molecule of carbon monoxide; the mass of the carbon monoxide molecule is equal to the mass of the oxygen atom plus the mass of the carbon atom


b) the reverse holds true as well











Law of definite proportions and Law of multiple proportions (picture on left)
a) carbon monoxide molecules are always composed of one carbon atom and one oxygen atom
b) carbon dioxide molecules are always composed of one carbon atom and two oxygen atoms; note that a molecule of carbon dioxide contains twice as many oxygen atoms as does a molecule of carbon monoxide

Dalton's Atomic Theory

• all matter is composed of extremely small particles called atoms
• atoms of a given element are identical in size, mass, and other properties
• actually atoms of a given element have the same number of protons not mass
• atoms of different elements differ in size, mass, and other properties
• atoms cannot be subdivided (chemically, they can in a nuclear reaction however), created, or destroyed
• atoms of different elements combine in simple whole number ratios to form chemical compounds
• in chemical reactions atoms are combined separated, or rearranged

Modern Atomical Theory

• atoms are divisible into smaller particles such as protons, neutrons, electrons, etc.
• a given element can have atoms with different masses (isotopes)
• all matter is composed of atoms

Structure of the atom

• atom is the smalles particle fo an element that retains that element's chemical properties
• nucleus is the very small region located at the center of the atoms
• the nucleus is made up of at least one charged particle called a proton and usually of one or more neutral particles called neutrons
• surrounding the nucleus are negatively charged particles called electrons which are found in electron clouds
• all these are called subatomic particles

Discovery of electron

cathode rays and electrons-- experiments in late 1800s shoewd that cathode rays were composed of negatively charged particles called electrons

charge and mass of electron: JJ Thomson's cathode ray tube experiments measured the charge to mass ratio of an electron

Robert A. Milikan's oil drop experiment measured the charge of an electron

later scientists were able to combine the findings of these two experiments to figure out the mass of an electron

?

Why did Griff not post?

September 2, 2009

Chapters 1 & 2 Test
Answers to Monday's test:

Dr. Bautista: Griff had some trouble getting this to post yesterday so you guys can comment on this one or tonights posting!

1. periodic chart*
2. glue gun melts a glue stick
3. 3
4. 19.3 g/cm^3
5. g/m^2
6. 91.4 cm
7. 4.05 g
8. centimeter
9. 10,080 min.
10. equation graphs as a straight line
11. meter
12. vitamin C (absorbic acid)
13. the smallest unit of matter that maintains its chemical identity
14. 0.036 g.
15. 3
16. 4.3 x 10^-7
17. 9.30 x 10^-3
18. to gain knowledge
19. 4.5 g
20. millimeter
21. discarding data inconsistent with the hypothesis
22. any substance that has a definite composition
23. compound*
24. 1.246 x 10^8
25. precise, but not accurate
26. melting
27. salt crystals formed as the liquid evaporated
28. 0.202 g
29. brittle
30. long after the basis resaerch is complete
31. liquid
32. 4.1 cm^3
33. density
34. volume

1* If you answered "None of the above", and it would change your quarter grade, see Dr. Bautista at the end of the quarter and she may change it. 23* Compound is the answer given by the book but Dr. Bautista said it could be "element" so this question didn't count for anyone.

NOTES

Foundations of Atomic Theory:

- The transformation of a substance or substances into one or more new substances is called a chemical reaction

3 Laws:

The Law of Consecutive Mass

- Mass is neither created nor destroyed during ordinary chemical reactions or physical changes.

The Law of Definite Proportions

- A chemical compound contains the same elemens in exactly the same proportions by mass regardless of the size of the sample or source of the compound.

The Law of Multiple Proportions

- If 2 or more different compunds are composed of the same 2 elements, then the ratio of the masses of the 2nd element combined with a certain mass of the 1st element is always a ratio of small whole numbers.

P.S. -Our first lab will most likely be at the end of next week