Wednesday, May 9, 2012
Acids and Bases
Acids and bases differ in that acids release protons and bases recieve protons. They transfer these protons in the form of an H+ molecule, making them either basic or acidic from the transfer of that molecule. Solutions are determined to be either acidic or basic depending on their placement on the Ph scale. A solution's postition on the Ph scale can be determined by placing a Ph test strip in the solution, waiting for the strip to change color, and looking at the color key that (should) come with the strips. The key may have a number scale, which should read from 0 to 14. If a solution is below 7 on the scale, it is labeled as acidic. If a solution is above 7, it is labeled as basic. The severity of how acidic or basic it is. The lower on the scale it is, the more acidic it is. The higher on the scale a solution is, the more basic it is. Solutions on the number 7 mark are labeled as neutral, making them less likely to transfer H+ ions. Acids contain more hydrogen while bases contain more hydroxide ions because of their individual transfers of ions.
Beer's law lab
Beer's law states that the more concentrated a solution is, the darker it will appear because of the presence of more of the solute.
Purpose- Determine concentration of solutions based upon how dark the solutions are.
Materials- Nickel Nitrate, clear (clean) test tubes, pipets, distilled water, colorimeter (yes, that's its name), cuvettes and a computer to record data.
Procedure-
Create control for experiment by filling one cuvette with only distilled water and entering in the data from the colorimeter to the computer. Then, switch the colorimeter's settings to red light (as we're dealing with a green-colored solution). Next, add in different ratios of Nickel Nitrate to distilled water in different test tubes, but only so that the result is a total of 10mL of mixture (Ex: 2mL of Nickel Nitrate to 8mL of water, 4mL of Nickel Nitrate to 6mL of water and so on). Stir all test tubes full of the different concentrations of Nickel Nitrate so they are all properly mixed with the distilled water in the test tubes. Enter in all data from colorimeter to computer by pouring one cuvette with one of each of the different of mixtures created so there is one cuvette for each different mixture ratio. The data entered should have aslightly linear pattern, although we experienced one outlier in our data. In the case of an outlier, it is advised to draw a line of best fit into the graph to determine an estimated trend of concentration. Then, we were given 3 unknown mixtures that were prepared before the experiment and needed to apply our knowledge and data to determine the concentration and absorbance of each of them.
Absorbance for the 3 unknowns were:
1- .186
2- .551
3- .367
Concentration (in moles) were:
1- .155 M
2- .365 M
3- .26 M
Conclusion: Unknown mixtures' concentrations can be determined by the data recieved from known solutions and comparing their absorbance with the unknowns'. Thus, Beer's law is a reliable basis for this sort of experiment.
Purpose- Determine concentration of solutions based upon how dark the solutions are.
Materials- Nickel Nitrate, clear (clean) test tubes, pipets, distilled water, colorimeter (yes, that's its name), cuvettes and a computer to record data.
Procedure-
Create control for experiment by filling one cuvette with only distilled water and entering in the data from the colorimeter to the computer. Then, switch the colorimeter's settings to red light (as we're dealing with a green-colored solution). Next, add in different ratios of Nickel Nitrate to distilled water in different test tubes, but only so that the result is a total of 10mL of mixture (Ex: 2mL of Nickel Nitrate to 8mL of water, 4mL of Nickel Nitrate to 6mL of water and so on). Stir all test tubes full of the different concentrations of Nickel Nitrate so they are all properly mixed with the distilled water in the test tubes. Enter in all data from colorimeter to computer by pouring one cuvette with one of each of the different of mixtures created so there is one cuvette for each different mixture ratio. The data entered should have aslightly linear pattern, although we experienced one outlier in our data. In the case of an outlier, it is advised to draw a line of best fit into the graph to determine an estimated trend of concentration. Then, we were given 3 unknown mixtures that were prepared before the experiment and needed to apply our knowledge and data to determine the concentration and absorbance of each of them.
Absorbance for the 3 unknowns were:
1- .186
2- .551
3- .367
Concentration (in moles) were:
1- .155 M
2- .365 M
3- .26 M
Conclusion: Unknown mixtures' concentrations can be determined by the data recieved from known solutions and comparing their absorbance with the unknowns'. Thus, Beer's law is a reliable basis for this sort of experiment.
Crystal formation lab
This lab procedure was slightly trickier than the others in that it required a tid bit more finesse in going through the steps. Some of the smallest mistakes make the steps leading up to it all for nothing.
First, we needed to add a large amount of Aluminun Potassium Sulfate to a glass beaker of distilled water (the experiment will only work with distilled water). I did not use an exact measurement of Aluminum Potassium Sulfate due to lack of time, so all that I can say is that I added a good sized amount to about 250mL of distilled water. Then, we stirred the water until the Aluminum Potassium Sulfate had fully dissolved and made the water cloudy white. Then, we put our glass beakers on top of hot plates (basically safer, more portable stove tops) and continued to stir. After stirring for about 15 minutes, the solution inside the beaker had turned clear, signifying that it was time for the next step. We took our beakers off of the hot plates to let them cool and form seed crystals at the bottom. Then, we chipped away at the newly formed seed crystals until we a had a respectable-sized chunk that we could tie on a piece of string for the second main part of the experiment. (Note: if the seed crystal is not properly tied to the string, it will fall and ruin the experiment; as what happened to me)
Next, we repeat step one, except we don't let seed crystals form at the bottom. Instead, when we tied a seed crystal with the string, we tied the other end to a small wooden stick (much like a tongue-depresser). The reason for this is to suspend the seed crystal so that it sits in the middle of the glass beaker full of solution. (Note: wait until the beaker has cooled enough to be held or the seed crystal will dissipate) This caused the cooling to make the Aluminum Potassium Sulfate in the water solidify around the seed crystal instead of just the bottom of the beaker. So, basically, we covered the seed crystal in another layer of crystal. The result was this:
This lab lead us to learn two important lessons: 1. Solutions can have predictable reactions when solids of that solution are introduced to the experiment that produced the solutions. By dissolving a solute and making it a part of a solution, it can solidify around a solid in the water in which it was made. 2. Some experiments need careful attention to procedure to produce the right end product.
First, we needed to add a large amount of Aluminun Potassium Sulfate to a glass beaker of distilled water (the experiment will only work with distilled water). I did not use an exact measurement of Aluminum Potassium Sulfate due to lack of time, so all that I can say is that I added a good sized amount to about 250mL of distilled water. Then, we stirred the water until the Aluminum Potassium Sulfate had fully dissolved and made the water cloudy white. Then, we put our glass beakers on top of hot plates (basically safer, more portable stove tops) and continued to stir. After stirring for about 15 minutes, the solution inside the beaker had turned clear, signifying that it was time for the next step. We took our beakers off of the hot plates to let them cool and form seed crystals at the bottom. Then, we chipped away at the newly formed seed crystals until we a had a respectable-sized chunk that we could tie on a piece of string for the second main part of the experiment. (Note: if the seed crystal is not properly tied to the string, it will fall and ruin the experiment; as what happened to me)
Next, we repeat step one, except we don't let seed crystals form at the bottom. Instead, when we tied a seed crystal with the string, we tied the other end to a small wooden stick (much like a tongue-depresser). The reason for this is to suspend the seed crystal so that it sits in the middle of the glass beaker full of solution. (Note: wait until the beaker has cooled enough to be held or the seed crystal will dissipate) This caused the cooling to make the Aluminum Potassium Sulfate in the water solidify around the seed crystal instead of just the bottom of the beaker. So, basically, we covered the seed crystal in another layer of crystal. The result was this:
Flash Memory
View my Prezi presentation about my research on the subject of flash memory and how it works. The presentation includes a short history of companies who utilize and distribute flash memory-related devices such as USB memory units and SD cards.Some questions to review said presentation include:
1.What company is credited with first utilizing flash memory in the 1980's? (Toshiba)
2. What part of USB devices store information? (storage chip)
3. What are common types of devices utilize flash memory?(Memory cards, memory sticks, SD cards, USB drives)
1.What company is credited with first utilizing flash memory in the 1980's? (Toshiba)
2. What part of USB devices store information? (storage chip)
3. What are common types of devices utilize flash memory?(Memory cards, memory sticks, SD cards, USB drives)
Friday, March 16, 2012
Silver nitrate precipitate lab
Purpose: Find how much silver is produced from 1g of silver nitrate.
Hypothesis: If silver nitrate is mixed with copper wire, then one gram of silver precipitate will form on the wire.
Materials: Silver nitrate solution, copper wire, distilled water, test tube, beaker, filter paper and small funnel.
Procedure: Pour 1g of silver nitrate solution into the test tube, leaving enough room left for the copper wire. Carefully put on 30cm of copper wire into the test tube and tape over the opening of the tube. Let the wire sit in the solution for 24 hours. Upon return, position the funnel over the opening of the beaker and roll the filter paper to create a cone to catch any precipitate that may have formed from the reaction. Next, carefully remove the tape from the test tube and pour out the excess solution into the filter paper cone. Then, lightly spray the copper wire with distilled water, getting off any precipitate from the wire and into the paper cone. Once all remaining precipitate is in the filter paper, weigh the wire and the precipitate separately.
Conclusions: 0.35g of silver was produced from the reaction and 0.247g of copper was lost. Our original hypothesis was proven wrong, due to a miscalculation in stoichiometric equations which led us to the aproximate result of 1g of precipitate.
Hypothesis: If silver nitrate is mixed with copper wire, then one gram of silver precipitate will form on the wire.
Materials: Silver nitrate solution, copper wire, distilled water, test tube, beaker, filter paper and small funnel.
Procedure: Pour 1g of silver nitrate solution into the test tube, leaving enough room left for the copper wire. Carefully put on 30cm of copper wire into the test tube and tape over the opening of the tube. Let the wire sit in the solution for 24 hours. Upon return, position the funnel over the opening of the beaker and roll the filter paper to create a cone to catch any precipitate that may have formed from the reaction. Next, carefully remove the tape from the test tube and pour out the excess solution into the filter paper cone. Then, lightly spray the copper wire with distilled water, getting off any precipitate from the wire and into the paper cone. Once all remaining precipitate is in the filter paper, weigh the wire and the precipitate separately.
Conclusions: 0.35g of silver was produced from the reaction and 0.247g of copper was lost. Our original hypothesis was proven wrong, due to a miscalculation in stoichiometric equations which led us to the aproximate result of 1g of precipitate.
Thursday, March 15, 2012
Molar calculations
One mole is equal to 6.02 times 10^23. This number was introduced by Amedeo Avogadro to simplify a unit of atoms. An element's atomic weight is how many grams of weight are present in one mole of that atom. Percentages of elements present in a molecule of a substance, such as aluminum chloride, can be found by going through some simple mathematical steps; as shown below:
Wednesday, March 14, 2012
Popcorn lab
Purpose: find out how much of unpopped popcorn kernals' mass is made up of water.
Hypothesis: When popcorn kernals are popped, atleast one third of the total mass of the kernals will be lost due to loss of water caused by high temperature.
Materials: Glass beaker, vegetable oil, unpopped popcorn kernals, Bunsen burner, and foil.
Procedure: First, weigh the popcorn kernals and record the total weight befor reaction takes place. Next, fill the glass beaker with a small amount of oil to pop the kernals in. Put kernals in the beaker and cover the top with aluminum foil to keep heat inside the beaker. Poke holes in the foil to let pressure from the heated air escape. Then, place the beaker above a bunsen burner so that the flame heats the beaker evenly. Light the flame and wait for the kernals to pop. Then, remove the popped kernals and weigh them and record the difference in weight.
Results: One gram of weight was missing from the kernals.
Conclusion: The original hypothesis of one third of weight being lost from the reaction proved false. Though only a small amount of weight was lost from the lost water from the kernals, it was still apparant that the weight difference was caused by evaporated water trapped in the kernals. Based on the original weight of 6.5g of the kernals and the loss of 1g from teh experiment, it can be calculated that about 15.38% of the unpopped kernals' weight comprised of water.
Hypothesis: When popcorn kernals are popped, atleast one third of the total mass of the kernals will be lost due to loss of water caused by high temperature.
Materials: Glass beaker, vegetable oil, unpopped popcorn kernals, Bunsen burner, and foil.
Procedure: First, weigh the popcorn kernals and record the total weight befor reaction takes place. Next, fill the glass beaker with a small amount of oil to pop the kernals in. Put kernals in the beaker and cover the top with aluminum foil to keep heat inside the beaker. Poke holes in the foil to let pressure from the heated air escape. Then, place the beaker above a bunsen burner so that the flame heats the beaker evenly. Light the flame and wait for the kernals to pop. Then, remove the popped kernals and weigh them and record the difference in weight.
Results: One gram of weight was missing from the kernals.
Conclusion: The original hypothesis of one third of weight being lost from the reaction proved false. Though only a small amount of weight was lost from the lost water from the kernals, it was still apparant that the weight difference was caused by evaporated water trapped in the kernals. Based on the original weight of 6.5g of the kernals and the loss of 1g from teh experiment, it can be calculated that about 15.38% of the unpopped kernals' weight comprised of water.
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