

Welcome to our Chem Class. This site will be as meaningful and rich as YOU make it. You'll be surprised.




During the lab, we practices converting problems involving the atoms mass in grams. Each elements atomic mass on the periodic table is the amount of mass measured in grams per mole. For example, Al has an atomic mass of 26.98.
26.98g of Al = 1 mole of Al
Another way of saying this is that for every 26.98g of Al, there is one mole of Al.
We also were able to add up the masses of two different atoms such as (H2O) two Hydrogen and one Oxygen so that we were able to figure out that there are 18.02g in a single H2O molecule. Like the concept Al's mass of 26.98g being a mole, 18.02g of H2O is equal to 1 mole as well.
Next Scriber: Dan





After we finished our lab, we took a short quiz together with our lab group on things that we have learned recently. Tomorrow, Mr. Paek will try to find the "weakest link" in each group, and ask that person to explain how we got our answers.



Don't forget to read pages 253-258 in the book and answer question number 7 on page 258.
Also we have 2 web assigns.
The lab todaywas the Rutherford Simulation Lab, in the lab we took a piece af paper with six circles on it, and six small squares at the center of each circle. We layed a piece of carbon paper on top, and with a partner, bounced a marble on top of the paper 110-120 times. After we finished, we counted the number of dots: in the circles, in the squares, and out side of the circles.
Using the collected information we found various data, like the percentage of dots that landed in the circles, for example me and my partner got 69 dots in the circle, out of 120 dots. to get the percent divide the number dots in the circle to the number of total dots: 69/120=.575 or 57.5%.
then using the total area of the paper, 93.5in. sq., and the percent of dots that landed in the circle, we found an estimated area of all 6 circles. We did this by multiplying the area of the paper times the percentage in decimal form: 93.5*.575=53.76in. sq.
Using the information we just found, we divided by six to find the next question, which was, what is the area of one circle: 53.76/6=8.96in. sq.
Then we solved to find the radius. To do this divide bothe sides by pi, then the square of your answer. To solve for diameter, multiply the answer you just got by 2. 8.96/3.14159=2.85 then the square of 2.85= 1.689in is your radius. 1.689*2= 3.378in is your diameter.
For problem 7, use a similar process to find the area of a square, like finding the area of a circle. First divide the number of dots in the squares by 120, i got 2/120=1.56, then divided by 6 to get one squarer alone. 1.56/6=.259in. sq.
to find the length of a side, take the square root of the area of one square.
Question Answers:
What does the paper represent?
the gold foil
What does the circle represent?
the atom
What does the marble represent?
the alpha-particle
What does the square represent?
the nucleus of the atom
The true diameter of each circle is 3.2 inches. find your percent error. to do this subtract your value minus the true value, then divide by the true value, and multiply by 100.
>>> (3.378)-(3.2)=.178/3.2=.055625*100=5.5625%
What could account for your own error in this lab?
>>>answers may differ. ex: not enough data collected.
Modern View-electrons can be in ground or excited states and can jump between levels. When electrons drop levels (high to low) they give of a beam of light! Its like bees in a beehive and bees are electrons moving around the nucleus like a cloud. Similar to the picture above
Niel Bohr from 1914 discovered that electons(-charge) "ORBIT" around positive nucleus in different- ORBITALS(levels). Electrons can jump up and down these levels. As seen above.
Ernest Rutherford from the early 1900's shot alpha particles(+ charge) through gold foil as shown in the picture above. Most of them went through but some deflected and these some were - charged particles!
John Dalton was an english schoolteacher from the early 1800's. He thought that each element was mad of elements, an atom of one element would be identicle to an atom of the same element. Also atoms do not include the existence of the nucleus, dosen't explain the existence of ions or isotopes, and dose not talk about subatomic particles (electrons, protons, and neutrons). His view of the atom looked something like the picture above.![]() |
| Black container that contained the bead. There were 12 different containers with differents line patterns inside of them. (scroll down all the way for more details) |
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| Black box lab |
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| We did this sheet in class. The sheet had four atom scientists' names and we had to fill out information about them. The information can be found on the colored sheets pictured below. |
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| These are the colored sheets of paper with the information on four atomic scientists. (Dalton, Rutherford, Thomson, Bohr) |
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| 2nd part of the black box lab |