Acid and Bases

If people think anything like i do, they probably think what makes an acid an acid, and what makes a base a base? An acid is a substance that reacts with a base. Acids are known as being sour. They react with metals like calcium and bases like sodium carbonate. Acids donate hydrogen ions. Acids can also be dissolved in water when the balance between hydrogen ions and hydroxyl is shifted. A base is a substance that can accept hydrogen ions or donate electron pairs. Bases also become less basic when mixed with acids. Bases can be dissolved in water due to the balance between hydrogen ions and hydroxyl ions shifting the opposite way.

       To measure how acidic or basic a liquid is, scientists us a pH scale. Even though there are many types of ions n a solution, pH focuses on concentrations of hydrogen ions and hydroxide ions. The scale goes from 0 to 14, and distilled water is right in the middle of the scale at 7. Acids are found closer between 0 and 7. Bases are further away from 7 to 14. Most liquids usually have a pH somewhere near 7, either below or above the mark. When looking at the pH of chemicals, numbers are extreme! Some substances may value with a pH of one and the next could be a 14.

Here is a pH scale-

Beers Lab

This was again a pretty quick one day lab for me. We used a nickel nitrates solution and water. Then we had 3 different unknown nickel nitrate solutions. We had 5 test tubes and put a certain amount of solution and a certain amount of water in it. The first tube had 2 mL of 0.40 M NiSO4, and 8 mL of distilled water. The second tube had 4 M NiSO4, and 6 mL of Distilled water. The third tube had 6 mL of 0.40 M NiSO4, and 4 mL of distilled water. the fourth had 8 mL os 0.40 M NiSO4, with 2 mL of distilled water and five with ten mL of 0.40 M NiSO4, with no distilled water. After we did all of that, we put some of the solutions into Cuvettes and then into the colorimeter. What the colorimeter did was tell how much light would reflect from the solution. The darker the solution, the more absorbency it had and not much light could pass through. But the lighter the solution, the more light could go through it, because it had a lower absorbency. When we put the Cuvettes in the colorimeter, it graphed and told us on the computer the absorbency.
       We did this lab based off of Beer's Law. Beer's Law states that the absorbance is directly proportional to the concentration of a solution. If you were to plot the absorbance versus the concentration, the graph would be n a pretty straight line.

Crystals!

With it being closer to the end of the year, everything has been crazy! I was gone for pretty much the whole lab, but when Mr. Ludwig got back I made it up, with all of the other people who missed it too.
    The procedures for this labe were:

1. Obtain a good amount of distilled water and put it in a beaker.
2. Put aliminun potassium sulfate annd mix in distilled water until it is supersaturated.
3. After stirring, there were still crystals in the bottom of the beaker, so we then set it on a hotplate to let the crystals disolve, while stirring every couple minutes.
4. While the the aliminum potassium sulfate is on the hotplate, keep adding potassium sulfate until it is supersaturated as well.
5. Then we were supposed to let the mixture cool over night, but I did it all in one day, so i let it get cool enough to add my sea crystal on the string.
6. I then let the crystal sit over night in the potassium sulfate solution.

      The Next day that I came into class, My crystal had grown bigger, and a much smaller crystal had grown on the string a little ways from the bigger crystal that was tied to the string. I had a lot of fun learning how to make crystal :)

Chem Project

http://prezi.com/vnmleb_p6agw/alternative-fuels/

This is a link to my Chem presentation. I did mine on alternative fuels :)

Evaporation and Intermolecular Attractions

The procedures we did in this lab were:
1. We got a mac and plugged the temperature probe into the mac so we could record the data.
2. We got the probes and wrapped a piece of filter paper over it and wrapped a rubber band around it to keep it to stay there.
3. Then we next put the 2 probes in different solutions such as methanol and ethanol for about 15 seconds then put them out over the countertop and it evaporated up the solution as the rest of the program finished running.
4. We next did the same thing, but put the probes in 2 different substances which were Propanol and Butanol. We repeated the steps with taping them to the edge of the countertop and let the program finish running. The last two ones that we did were pentane and hexane. We did the same thing but it was weird in the hexane, it dissolves rubber, so while the probe was soaking up in the hexane solution for a while, the rubber band started to dissolve.

Data Analysis:
1. Most of these substances contain hydrogen bonds which is very apparent for 1- Butanol and n-pentane. Their weights all together were pretty much the same, but the temperature change was very different.  Hydrogen bonds were definitely the cause because 1- Butanol has hydrogen bonds, but n-pentane doesn't. That is why n-pentane evaporated the best.
2. Methanol had the weakest intermolecular forces out of all the ones that we tested. Where 1-Butanol was the strongest. Methanol had the weakest bonds because it's temperature change. Methanol changed 17.38 degrees, which is why it evaporated faster than all of the other solutions. 1- Butanol had a very low change rate, and that is why the bonds were so strong. So pretty much the lower the change in temperature, the stronger force it has.
3. Alkanes. n-hehane had the weakest intermolecular forces, and n-pentane had the strongest molecular forces. N-hexane changed 10.00 degrees, and n-pentane only changed 7.28 degrees.


Green- Ethanol, Red- Methanol



Red- 1-propanol, Green-1-Butaol






Red- n-pentane, Green- n-hexane

Silver Nitrate/ Copper Lab

 The first day of this lab we weighed out exactly one gram of silver nitrate and got a piece of copper and measured that out to be 3.444 grams. We put the silver nitrate in a test tube with water and coiled up the coper to make it fit in the test tube. Then we shook it up a little to mix the copper nitrate up. We then put a  parafilm cover over the top of it and let it sit over the weekend. The result was that the water turned blue from the copper and the silver nitrate built up around the coiled copper. The second day we took the copper out and poured it into a little filter with a beaker on the bottom and washed the nitrate off the copper.n The 3rd day, we weighed the copper and recorded its mass, then weighed the filter paper and recorded it's mass.   Mass of everything.
Silver Nitrate: 1.369 grams.
Copper Coil before: 3.68 grams
Copper Coil after: 3.26 grams
Copper Reaction: .423 grams
Filter Paper: 1.389 grams
Filter paper and silver together: 1.892 grams
Silver production in moles: .0032 moles
Copper Consumption: .0036 moles.

Hydrates Lab

     The equation that we used for this lab was CuSO4*5H2O. We chose to do the lab with the blue crystals instead of the epsom salt lab. We first weighed four little blue crystals in a plastic tray boat and got that it weighed 4.07g. We then put the crystals in a test tube and heated the crystals over a bunsen burner and while heating them, the crystals started to turn white as the water started coming off of them. After letting them cool off for a while, we weighed the crystals again and got 3.66g. When the crystals were squirted with distilled water they turned back to blue.
     The predicted weight that we got was about 10%. That was pretty different from the actual % we got which was 36%, because of the crystals that were stuck together and didn't get the water out of all the way. We subtracted the weight after heating from the weight before heating and that is how we got the 10% prediction. With the equation CuSO4*5H2O we multiplied the total CuSO4 mass by the 5 parts water. the total water mass is 90g, and the total mass was 249.6g. By dividing the 90g by the 249.6g, that is how we got the 36%.