Magnesium Oxide Lab

First we went over the pre-lab. For number....
1. Subtract the massof iron (85.65 g) from the mass of the iron oxide produced (118.37)
2. Using molar mass, (O= 16 G) Set up the conversion, which should be the number of grams you found in number one, (Oxygen) multiplied by one mole of oxygen over 16 g
3. Using the same method, you should be able to find the moles of iron (molar mass= 55.9)
4. Next set up the ratio of moles, which should be number of moles of iron over moles of oxygen. You should end up with 3/4, so the empirical formula should then be Fe3O4

In the lab, here is what we did.
Using a crucible, we heated the magnesium oxide with the Bunsen burner.
Every three minutes, you take the lid off and allow oxygen to get in the crucible, sometimes you could even see the metal glow when this would happen. After heating for a while, and cooling, we massed out the magnesium oxide product. The mass should go up, since we were adding oxygen through the experiment.

Empirical Formula

Today in class we went over some of the notes and discussed the empirical formula.
Sample Problem: 71.65% Cl, 24.27% C, 4.07% H
1. assume 100 grams
a. 71.65 g.*(1 mol./35.5 g.)
b. 24.27 g.*(1 mol./12 g.)
c. 4.07 g. *(1 mol./1g.)

2. convert grams to moles
a. 2.02 mol.
b. 2.02 mol.
c. 4.07 mol.

3. calculate ratio
a. 2.02/2.02=1
b. 2.02/2.02=1
c. 4.07/2.02=2.01=about 2

4. empirical formula is CClH2

5. relate empirical formula to molecular formula (molar mass)
(49.5 g.)*2=
98.96 g/mol.

The next scribe will be Bailey Monte

Hydrate Lab!

Today in class...

We started off by going over the quiz on Mole Conversions. For the rest of the class though, we did the Formula of a Hydrate Lab.

We started off by finding the mass of the empty test tube (to subtract it from the other masses later) and then the mass of the hydrate inside of the test tube

Next, we placed the test tube in the stand to heat it.
Then we began to heat the hydrate by using the Bunsen burner...

The blue hydrate eventually turned white, and it lost all of the water within it, the water left over towards the end of the tube can be seen below...


This new anhydrous salt was left, and we then had to find it's mass.


In the post lab, you should be able to use these masses to find moles of water lost during heating, the percent of water in the hydrate, the moles of anhydrous salt, and the ratio of moles of water lost per moles of anhydrous salt.

Percent Composition

Today in class we learned about percent compositions and took our quiz on molar mass and unit conversions.

To start class today we talked about percent composition. Percent composition is used to describe the make up of a compound by mass percentage. It compares the mass of each element present in 1 mole to the total mass of the compound.

In our notes we did this sample problem:

Find the mass percent of each element in C14H20N2SO4.

14(12)+20(1)+2(14)+32+4(16)=312 (The numbers in the parenthesis are rounded versions of the atomic mass)

This format is repeated for the rest of the components. The decimal answer you get is your mass percent.

% Composition of Bubble Gum

Yesterday in class we we began by briefly reviewing for our quiz which was pushed back until today. After our review of unit conversions and molar mass problems we began the Percent Composition of Bubble Gum Lab.

In this lab the purpose was to find out the percent sugar in bubble gum and write an empirical formula for bubble gum. The notes on empirical formulas will be displayed in a later post.

Here is the procedure for this lab:

1. Obtain a piece of bubble gum and its wrapper. Record the mass of the gum and its wrapper.

2. Unwrap the gum (save the wrapper). Chew the bubble gum. While Chewing the gum record the mass of the wrapper.

3. When the gum has lost its sweetness, place the chewed gum in the wrapper and record the mass of the gum and its wrapper.

Note: In this lab our class used Double Bubble chewing gum because as Mr. Lieberman said, "Double Bubble is the worlds greatest gum, for 15 seconds."

The calculations for this lab are due on Friday.

More Unit Conversions

Today we learned about conversions.

We started today looking at some more problems and explanations of molar mass and how to use it. Again molar mass is just the mass of 1 mole in grams. This is found on the periodic table and it is the atomic mass.

Look on the last post for examples of what the equations look like.

One of the most important things we learned today was that EVERYTHING must go through moles.

If it is Grams to Particles,it has to go through moles and if it is Particles to grams then it also has to got through moles.

We then did some learning checks problems like the Nutra-sweet problem. For problems like those to calculate the molar mass of something you take each element and treat it like its own part. For the Nutra- Sweet problem it would look like this

C14H18N2O5

(12x14) + (1x18) +(14x2)+(5x16). this is how you find the molar mass of a compound, then you complete the problem like a simple one.

After that we then had the rest of the class period to work with our partners on the Mole Workshop. Those problems are tricky they just need to be thought out and make sure to show your work. Remember that only one person in your pair needs to turn it in tomorrow but it is best if both partners do the work. I am sorry that I can not post the notes on here, I can not seem to find them on slideshare but if you have any questions just post it here or ask a teacher. This website http://www.chem1.com/acad/webtext/intro/MOL.html could also assist you.

Homework tonight: Finish the Mole Workshop and the other Mole worksheet

Study for the quiz tomorrow over dimensional analysis and unit conversions.

Test is coming up the 28th.

Alright well thats all I have have fun studying.

next scribe is Trevor. have fun

Bobby

I want a Number and Guacamole Named after Me

Hey sorry for the late post but this is for yesterdays.

To start of the day we went over the test we took on Friday and were told if we needed any help naming, the best thing to do was practice and more practice. After that we started looking at our notes about Avogadro's number. That number would be the mole. Is written in scientific notation as 6.02x10^23 or 602 billion trillion or 602,000,000,000,000,000,000,000. My recommendation is to keep it in scientific notation. The mole is only used when talking about Particles and molecules, things that are REALLY small. The mole is used in the same way that a dozen is used.

Ø 1 dozen cookies=12 cookies

Ø 1 mole of cookies=6.02x10^23

Ø 1 dozen cars=12 cars

Ø 1 mole of cars=6.02x10^23

The number will always be the same but the mass will be different. on a side note- mole is abbreviated as "mol" but in liebs class we feel that we deserve our own symbol that is shorter and more convenient so we chose a circle with a line through it. I would post the notes here but I can’t find them, they are not on slide share so I will just go on to conversions.

6.02x10^23/ 1 mol OR 1 mol/ 6.02x10^23 will always be used it depends on what you are trying to get. I will discuss which one to use in the section about general concepts below.
After we talked about Avogadro's number we went on to molar mass.

Molar mass is the mass of 1 mole in grams. This number is equal to the numerical value of the atomic mass found on the periodic table. For example:

Ø 1 mole of H atoms = 1.008g

Ø 1 mole of C atoms = 12.0g

Ø 1 mole of Bi atoms = 209.0g

As i am finishing up i will end with some general concepts to keep in mind when dealing with calculations involving moles

Ø For moles to particles, multiply by Avagadro's number (mole)

Ø For particles to moles, divide by Avagadro's number (mole)

Ø For grams to moles, divide by molar mass

Ø For moles to grams, multiply by molar mass

Well I am done for now - if you want to get a sense of how big a mole actually is you can check this out, http://www.youtube.com/watch?v=1R7NiIum2TI . This video is just showing how insanely big a mole is. Have fun

The next scribe is me. so until later tonight, have fun working on the worksheets we got and studying for the quiz tomorrow over conversions using moles and such and dimensional analysis.

Unit Conversions

In chemistry today we started our first day of chapter three. In this section we learned about unit conversions. D Liebs gave us notes and lectured us for the majority of the class. You can find the notes on Moodle. Anyway first we discussed unit factors. A unit factor is basically a ratio. For example, if you want to say, there are 5280 feet in 1 mile, you would write it as: 5280 ft/1 mile. This is an example of a unit factor.

Here is an example of a unit conversion problem:

Convert 45 miles per hour to feet per second. Well to solve this problem first set up this fraction:

45 mi/1 hr

Now we have to multiply this unit factor by many others so that we can get the units to be feet per second. To do this, first think how many seconds are in one hour. Well there are 3600 seconds in one hour, so set up the fractions next to each other like this:

45 mi/1 hr * 1 hr/3600 sec

Note that in the first unit factor the hours is in the denominator. But in the second unit factor the hours is in the numerator. You must set up the units like this so that when you multiply across, the units will cancel out.

Now you have to cancel out the miles. But we need to think about how many feet are in one mile because we are trying to get feet/second. So now we multiply the fractions like this:

45 mi/1 hr * 1 hr/3600 sec * 5280 ft/1 mi

Remember to put the miles in the denominator, because in the first fraction the miles are in the numerator. Okay the last step is to multiply all of the numerators together and then divide that number by all of the denominators. So you do:

45 x 1 x 5280=237600
237600 / 3600= 66

Now you cancel out the units and you are left with feet in the numerator and seconds in the denominator. So the answer is 66 ft/1 sec.
After D Liebs explained the notes and such he gave us the rest of the class period to work on the worksheets with solving unit conversions. I know I was supposed to post this a little while ago but Blogger was not working. I also wanted to put some real fractions in the blog but copy and paste does not work well in Blogger. Well that's all for today, the homework was the WebAssign and complete the unit conversions worksheets.

Next scribe is................................................ Robert S.

Covalent Compounds and Acids

Today in class, we picked up two worksheets: Naming Practice and Naming Covalent Compounds. You can find these here.We went over any questions we had on the Naming Compounds sheet. For 6 i. Mr. Lieberman made a mistake! The actual answer is Co2(Co3)3. All the numbers should be little and on the bottom. After getting all of of questions answered, we buddied up to work on the naming compounds.
Here are the main points of covalent compounds.

• They only bond with eachother if they are nonmetals.
• The first word is the elements name
• If there are more than one atoms in any of the elements, you put a prefix in front of it.
• 1= mono (You don't use that) 2= di 3=tri 4= tetra 5=penta 6=hexa We only need to know up to 6
• The second word always ends in "ide"
• Examples: DiSulfur Dichloride= S₂Cl₂ Sulfur Dioxide= SO₂

After doing the worksheet we went to the notes. We started off learning about Binary Molecular Compounds (Covalent Compounds). The rules are above. We then looked at acids. If the compound starts with an H, then it's an acid. Click here for the notes.

After learning all of these things we had a little game to practice naming bonds.

Warning: There is a pop quiz tomorrow. It will be on measurements. Just kidding. It will be on naming bonds. That's it for today. If you have any questions, just email Mr. Lieberman or look back at your notes/book. The scribe for tomorrow is Justin J!

Naming Compounds

Hello. Today in class we learned about naming compounds. We were given two worksheets in class. We started out class by working on the worksheets with a partner and then we later discussed them in class.

The worksheets were about naming and writing ionic compounds.
Here are some patterns that take place in ionic compounds:

• All compounds are made up of a nonmetal and metal.
• The 1st element listed in the compound is the metal. It always ends in "um" (ex: sodium chrloride)
• The 2nd element listed in the compound is the nonmetal. It always ends in "ide" (ex: calcium chloride)
• Compounds always have a neutral charge.
• The 1st element listed is also always a positive ion.
• The 2nd element listed is always a negative ion.

If you follow these rules, you will easily be able to write or identify compounds.

The rules change a little bit if the compound involves a transition metal.

Here is how the rules change:

• The 1st element listed is still the metal but it no longer ends in "um" (ex: iron (II) chloride)
• Roman numerals are placed after the transition metal. The roman numerals indicate what the charge of the transition metal must be in order to make the charge of the compound neutral. (ex: iron (II) chloride. Since the charge of chloride is -2, iron must have a charge of +2 in order to make the compound neutral.)

The rest of the rules stay the same for transition metals. You can tell the the compound involves a transition metal if there are roman numerals written in the name.

That is basically all we learned in class today. If you need more help, I would suggest reviewing the notes or rereading the book. The homework for monday is to finish the worksheets and do the chemthink about ions. There is also a test on thursday.

The next scribe is Lauren C.!

Ions

Today in D Liebs' class we learned all about the wonderful world of ions. We started off class watching a video on what happens when you mix sodium and chlorine to make table salt.
Next we started looking at the notes on ions. Most of this is covered in the ChemThink that is due Monday. Since the notes were not online yet, I will just have to inform you myself.
Ions

• When atoms or molecules gain or lose electrons, they become charged particles called ions
• Positive Ions = cations
• Negative ions = anions
• There is never a change in the number of protons

Noble Gas Connections

• Atoms that are close to a noble gas form ions that contain the same number of electrons as the neighboring noble gas atom

Names of Compounds-Cations

• Monatomic cations take the name from the metal from which they form
• If more than one charge is possible, a Roman numeral is used to denote the charge

Names of Compounds-Anions

• Monatomic anions are named by adding -ide to the stem of the name of the element from which they form

Oxoanions

• When a nonmetal forms two oxoanions, -ate is used for the one with the larger number of oxygens, -ite is used for the one with the smaller number of oxygens
• When a nonmetal forms more than two oxoanions, prefixes are used. -per (largest # of oxygens) -hypo (smallest # of oxygens)

Ionic Compounds

• Combine the name of the cation with the name of the anion

That raps up the notes covered today. Along with the homework assigned earlier of the WebAssign( due tomorrow), The ChemThink (due Monday), the book problems given at the beginning of every chapter, and the extra problems 17-24 (both due on the day of the test), we got two new worksheets today. If you are still confused about Ions, you can read section 3.1 in the textbook.
The next scribe will be Paige H.

The Periodic Table of Elements.

Most of class today was spent talking about the Periodic Table of Elements. After we spent the first ten minutes of class working on an isotopes worksheet with partners. I can't get the PDF on my computer, but the page with the download on it can be found here. The worksheet is due with the test, per usual. Some hints for the sheet are: protons never change amount, mass number is the protons plus the neutrons, and always include the mass number when writing the isotopic symbol.

While working on the worksheet, Mr. Liebs played some songs for us regarding the periodic tale that might help us remember the elements names. The first one is by the famous math professor Tom Lehrer.


The second is less comprehensive but is still good, and is by They Might Be Giants.


We then went on to talk about how the periodic table is divided up. More simply divided tables will show the distinction between metals, metalloids, and non-metals.(I would post a picture but blogger's not allowing me to. A good link to one can be found here.)

A more detailed table will show more of the families, which consist of alkali metals, alkaline earth metals, transition metals, halogens,and the noble gases. (Again a good picture may be found here.)

We also started to take notes on the founder of the original periodic table, Dmitri Mendeleev. What's more impressive than his table was his prediction of elements that had yet to be discovered, and some of their properties. He left spaces in his table for his predictions, many of which were very accurate. Just for kicks and giggles, Mendeleev's orginal table looked like this.

And that pretty much wraps up today. The homework is ChemThink: Atoms-Ions, Webassign Reading Sheet and questions 17-24 in the book. The next scribe is Sarah G. Have fun.

Periodic Table of Aliens

Hey everyone!

Today, we started a “Periodic Table of Aliens” with our partners.

Basically, we arranged Aliens in an 8 x 5 chart by organizing the groups (columns) and periods (rows) with similar features.

Since there is only one way for the chart to work, you should have ended up with something like this:

(If you didn't, you probably want to fix that by tomorrow...)

Here's how it was done:

The Periods (rows)~

The periods were simply grouped together by the shape of their bodies: The first row is triangle, second row is circle, third row is rectangle, fourth row is oval, and the fifth row is upside down triangle)

And it would specifically be in that order because of the number of stripes/squiggly lines/cones/lines/etc. on their bodies: all the triangular-bodied aliens, which is the first row, had only one (let's say, cone) on their head.

The Groups (columns)~

Organizing the groups were pretty simple once you've figured out that there were similar features for each column.

1. Number of cones on their head

2. Number of sticks on their head

3. Start with short legs, then start getting longer

4. Number of stripes across their body

5. Number of stripes on top of their head. (Side Note: You should notice that one seems to be missing in the last row; the directions state that there are two missing from the whole chart, so it's okay)

6. Number of squiggles on their head

7. Number of rectangles on their head

8. Number of legs (starting with 2 legs and one is missing from this column too)

The aliens are specifically charted in this order by the number of fingers they're holding up. (If they were holding 1 finger, they'd be in the first column; 3 fingers, the third column, etc.)

After you get this chart done, there are other questions in the packet, so make sure to get that done. In addition to this Period Table of Aliens, you also have the Oleic Acid Lab due tomorrow and a WebAssign coming up on Oct. 8 (Friday).

And that's all for today!

The next scribe is.... Faith S.

Metal, Nonmetal, Metalloid Lab

Hey you guys, sorry I am putting this up a little late!

Today's class period was spent doing the metal, nonmetal, and metalloid lab. If you were absent on Friday when we got the lab you can get it here.

In this lab we tested 8 elements; aluminum (Al), carbon (C), Iron (Fe), Magnesium (Mg), silicon (Si), Sulfur (S), tin (Sn) and zinc (Zn) for 4 psychical properties and their chemical property.



For Each of these 8 elements we looked at their appearance and looked for luster(if they were shinny or dull). We also tested for their malleability. Which means when we hammered them, were they flat or did they break. And last we tested for their electrical conductivity.


What you see here is the malleability test being conducted.


This is the object we used to see (well actually hear) the electriacl conductivity. (If anyone has any cards with sound in them, you can brign them in to Mr. Lieberman)

After looking at the physical properties were tested their chemical properties by taking a little bit of each of the elements and putting them into 2 test tube. Then we add hydrochloric acid to one test tube and observed the changes and to the other test tube we add copper chloride and also observed the changes and made note of these in our data table.

Your homework for tonight is to work on the lab which is due on Wednesday, to do the webassign for tomorrow and to do the chemthink which is due next Monday.

That was all for today!
and the next scribe is.................. Rachel K. Good Luck!