Tuesday, May 13, 2014

Who Knew Chemisrty Had So Much Math?

One of the first few times we used math in chemistry was to convert things. We started with converting Joules to Kilojoules and cal to Cal, vice versa. Then we moved on to moles which was almost the same process; you put the measurements with the same units one on top and the other on the bottom so when you cross multiply to solve the same units would cancel each other out. Now we're doing solutions and while learning about solutions I learned there is a lot of math in chemistry. Mostly just multiplying and adding but there’s still a lot of math involved in the process. We've used the most math in figuring out the concentration of a solution or how to dilute a solution or find how many grams/milliliters of the substance you need. But before I get into all of that there are some things you should know. The definition of a solution is a mixture of two or more substances that consist of ions. Solvation is the process of surrounding solute particles with solvent particle; basically putting what you want to dissolve in water. Along with this definition there are factors that can affect it. To speed the solvation you can agitate the particles by shaking or stirring them, the particles size can also affect it because of the surface area, and also raising the temperature can speed up the reaction. The difference between Concentrated Solution and a Diluted Solution is the concentrate has more solute and the dilute has less solute, To see this we made a solution and then diluted it in a lab and for a practical on a quiz. For the lab we first had to get the concentration we would have and we were supposed to be trying to solve for the amount in gram of the substance we need to make that concentration in the solution. After that we did the math and found the number of grams. So we filled the flask half way with water, pour the substance in, capped the top and shook it. When we could see there were no more particles left we filled the rest of the flask you until the marked white line. This was all just for the concentrated solution. To make the diluted solution we got the concentration for our teacher then had to figure out how many ml if the concentrated solution we would need to get the new concentration. After we did the math we measured out the amount of mL we needed in a graduated cylinder, filled the flask half way with water, poured the concentrated solution form the graduated cylinder, capped it and shook it .The way we could tell it was diluted was because the dilute was always lighter that the concentrate.

Monday, March 31, 2014

Hydrate

When you see the word or suffix "Hydro" what does it make you think of? I automatically think about water. There are plenty of ways hydro is used in Chemistry. You can use it when you say hydrophobic (water fearing), Hydrophilic (water loving), or hydrate (water and compound combination). The official definition for a hydrate is a solid compound in which water molecules are trapped. When you write a hydrates formula you use a dot. You write the compound and after you put the dot then write the water formula and if there is more than one molecule of water then you write that number before the water compound. You have to write it like this because the mass of the water is included in the molar mass of the compound. So this way you won’t get the mass of the compound wrong. If you want to find the mass of the compound with the water then you find the mass of the compound then the mass of the water compound and add them together. If you want to find the mass of the compound without the water the first you have to find the mass of the compound with the water then find the mass of the water and subtract them. If you make the compound react to get a certain amount the you divide the mass of the compound only by the mass of the compound with the water the cross multiply that mass of what your trying to get from the reaction over "x" to see how much of the compound you will need to get that amount out of the reaction. We used this method in a hydrate lab. We had to determine the mass of CuSO subscript 4 with 5 water that would be needed to get 0.60 grams of anhydrous compound. First we had to mass the empty test tube then mass the compound in the test tube.
Once we got this measurement we subtracted then the set you the aporatious with the test tube and Bunsen burner. We moved the Bunsen burner around until all of the compound turned grey, let the test tube cool and remassed it.
My partner and I got the amount just right at 0.04 grams.

Tuesday, March 25, 2014

Isn't a Mole a type of rat?

What is a mole? Is it a animal? It rhyms with hole so does it have something to do with a hole? The way a mole is used in science is to get a common relative mass. The measurement for one mole is 6.02 x 10 raised to the 23 power. You can use the mole for atoms, molecules, and formula units.The molar mass is mass of one mole. The molar mass of an element is the same as the mass on the periodic table. To get the hang of it we did a lab to help us understand it better. First we had to find the molar mass of the Na(HCO subcript 3) and CO subscript 2. On oder to do that we mass the atomic mass bu the number of the element used and add the elements together and that gave us the molar mass. Then we found the theoretical percent of carbon dioxide/ sodium hydrogen carbonate. After we had to get about 4.0 grams of sodium hydrogen carbonate and put it in the Erlenmeyer flask. Next we put 40 mililiters of 3.0 M acetic acid into a 50 mililiter beaker, placed both the flask and th beaker on a tray and massed everything. After we massed everthing we took it all back to our station and poured the acetic acid into the flask slowly and waited for it to stop bubbling so that we knew the reaction had stopped. So we remassed everything subtracted the original mass from the mass of what was left after the reaction to get the mas of what was lost in the expirement. This experiment helped with the understanding of a mole because at the end we had to figure out how many moles where in the compounds and how many atoms or grams where in the one mole of the substance.

Monday, March 24, 2014

What kinds of attractions are these?

There are all different forces of attraction, There's an attraction between friends. magnets, a relationship, molecules, or atoms. In this particular blog I'm going to talk about the forces between molecules and atoms. The first is INTRAmolecular forces this creates an attraction between atoms, and is the stronger of the two. The attraction can be Ionic, Covalent, or Metallic. Ionic Bonds are strong and can be made only between metals and non-metals
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Covalent  bonds happen between non-metals and are fairly weak

The Metallic bonds are a bond between the same type of atom. 
The INTERmolecular creates an attraction between molecules, this is the weaker of the two. INTERmolecular forces come in four different types: Ionic, Dispersion, Hydrogen Bonds, and Dipole-Dipole Forces. Ionic forces in a molecule are like the forces that hold a atom together, they only happen between a metal and a non-metal. Dispersion the the weakest force because it temporary. The bond can only take place between Non-Metal Molecules. When molecules are attracted together by dispersion an electron cloud forms at one end of the molecule making it slightly negative, while the molecule next to it becomes slightly positive on one end so they don't repel from each other. Hydrogen Bonds are the strongest. Hydrogen bonds can only take place between a Hydrogen atom and a Florine, Oxygen, or Nitrogen.
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Dipole-Dipole Forces are permanent and the second strongest compared to Hydrogen Bonds. They only happen between polar molecules which means the the molecule as a whole is not symmetric. They also arrange themselves so the slightly negative end of the molecule is attracted to the slightly positive end of the other molecule
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Sunday, February 9, 2014

These Aren't the Same Shapes You Learned in Kindergarten

In Chemistry we have been learning a lot about chemical bonds and how it plays into their shape. To help us learn what element will bond with another element we use the periodic table. The periodic table is organized for this. There are s,p,d,f orbitals on a atom determines how many electrons an atom will contain. To know how many elements will bond with each other or if they will bond at all you have to pay attention to which row it is in on the periodic table. Besides the transitional elements the rows tell how many valence electrons the atom has. All atoms want to have a full valence electron shell of 8 electrons. Without the 8 electrons in the outer shell the atoms are unstable and want to bond to be stable. The only naturally stable atoms are those of noble gases. Although atoms want to be stable there are some that have a few exceptions. Hydrogen is stable with the first energy level being full with 2 electrons, Beryllium is stable with four valence electrons, Boron is stable with 6 valence electrons, and Sulfur can make more than 4 covalent bonds- when atoms share electrons. The way to draw out a chemical bond is with the Lewis structure.
With this we learned what the central atom would be, how many bonds it will make, and what it would bond with. First you count how many electrons the the compound will make. The write the symbol for the element. To show the elements are bonded you draw a line. There could be one to three lines.
One line represents a single bond, two lines represent a double bond , and three lines represent a triple bond. You have to try to make all the atoms stable and if there are any electrons left over you attach them t the central atom by adding 2 dots. Once you have drawn out the Lewis structure it helps you determine the shape of the atom.
You deteremine the shapes by the amount of bonds or the amount of extra left over electrons, Each shape has a different name that has all to do with the shape.