Stoichiometry Lab Report
Hugh Kim
Lab Report: Stoichiometry Lab
1. Prelab
Part1.
1) Create no waste = The principle that encourages chemists to not create waste at the first place rather than cleaning it up afterwards effectively shifts the chemistry more environmentally conscious, as creating no waste would make the experiment efficient; the reactants will be reduced to only the essential ones and the product will be maximized, a change that would make the experiment economic. Also, if chemists aim to engender no waste, this principle would solve the problem of disposal; as waste is often disposed by throwing it away in the nature, less waste possible will inflict less harm to the environment. Also, sometimes, the left over from the experiment …show more content…
causes disposal problems, as the experiments creates wastes that are hard to eliminate such as those with toxicity. For instance, during drug manufacturing, it often coproduces 100kilograms of waste for 100 kilogram of the desired product; however, if the green principle is applied, the waste can be reduced to 1/10. Thus, when choosing from two possible chemical processes chemists should consider preferring one that leaves less waste over the others, as leaving no waste contributes tremendously to environmentally conscious experiments.
2) 127.092g Cu/171.103g Reactants X 100 = 71.27%
63.546g Cu/95.546g Reactants X 100 = 66.50%
3) (a) the first process
(b) Atom economy informs the experimenters about the efficiency and economical aspect of the experiment. As high atom economy indicates that the experiment created more desired product and less waste, a indication of a green experiment. Thus, according to the principles of green chemistry, as the experiment with high atom economy creates less waste, makes the energy usage efficient, and gets rid of all nonessential additives( reducing non-essential reactants), a process with the high atom economy means that it is greener than other experiments. In essence, an experiment with high atom economy leads people to not waste any atoms; thus, people will utilize the rare and scarce resources more efficiently, and reduces the amount of waste that could harm the environment.
(c) The principle of using materials that break down in the environment also effectively leads the experiments to be greener, as left over reactants would not cause any disposal problems. Also, if the experiment yields biodegradable products from environmentally friendly reactants, this would also eliminate the concern of disposal problem such as waste of energy for disposing unsafe materials and would create smaller amount of toxic products. Also, biodegradable products will decrease the exposure of inherently dangerous chemicals to other animals or plants.
4) Peer review is crucial part of experiments.
Peer review is a process of rendering other people with the knowledge of the subject to check the process and the result that the experimenter has yielded. Thus, receiving peer reviews before publication is significant, as peers with different perspectives can point out and inform the experiments about the errors, any possible source of obfuscation, misleading parts and parts that the experimenter might have not considered. It also generally increases the quality of the report after the discussion with peers. Thus, chemists whose process could be propagated and could be used by others, wrong instructions could lead people to cause mistakes, and dangerous accidents. Thus, to reduce those risks, peer review could offer great benefits of making the experiments more secure. In essence, the results without any peer reviews has a higher chance of containing errors, a phenomenon that should be prevented before reporting the results of chemical …show more content…
process.
Part2.
CuSO 4-xH2O (s) -> CuSO4(s) + xH2O(g)
Initial mass: 0.1457g
Final mass: 0.0931g
0.1457g – 0.0931g = 0.0526g
0.0526g/0.1457g = 36.10% H2O
0.1457g X 63.9% = 0.0931g CuSO 4
0.0931g CuSO 4 X (1mol CuSO 4/63.546g+32.06g+64g) = 0.000583 mol CuSO 4
0.0526g H 2O X (1mol H2O/( 2(1.008g)+16g))= 0.00292 mol H2O
0.00292 mol H2O / 0.000583 CuSO4 =5.00
Thus, there is 5H2O
1) Chemical substance is a form of matter that has definite chemical composition and properties. It cannot be separated into smaller components without the chemical reaction that break the bonds.
Mixture is a combination of few different substances which are mixed physically but not chemically bonded.
Mixture is a combination of substances, like pebbles and dirt in water, but they still retain their own chemical compositions and did not react with each other chemically.
2) Separation of mixtures is often done based on chemical properties or physical properties like size, shape, mass, density, adsorption, solubility, volatility or chemical affinity between the components of the mixture.
3) The two methods of calculating the efficiency of a reaction, percent yield and atom economy, is same in the aspect that high number of both equations indicate that the product is generated economically and efficiently, reducing the waste as much as possible and maximizing the desired product. On the other hand, percent yield calculates the efficiency of the experiment while atom economy calculates the efficiency of the equations. In other words, percent yield shows how close the actual yielded result in real experiment is to the ideal result and atom economy shows which equations or processes will generate more desired products efficiently in an ideal condition.
2. Procedure
Materials:
Mixture of NaHCO3 and Na2CO3 with unknown ratio
Crucibles
Analytical balance
Clay triangle
Ring stands
Bunsen burner
[1] Weigh the crucible
[2] By using the analytical balance, put 2.00g of the mixture into the crucible
[3] Put the Clay triangle on the ring stand, and then ignite the fire of Bunsen burner.
[4] Heat the crucible for 2 minutes, turn the fire off and cool it down for 1minute and 30 seconds.
[5] Weigh the mass with analytical balance, and record the decreased amount of mass
[6] Repeat the step [4] and [5], until mass would not reduce after the mixture is heated.
[7] Record the mass of the ultimate result, subtract the mass of crucible from the result and then figure out the amount of evaporated H2O and CO2.
3. Data and Results
-Result of the experiment
Mass of the mixture before Heating
Mass of the mixture after 1ST heating
Mass after 2nd heating
Mass after 3rd heating
Mass after 4th heating
2.00g
1.611g
1.607g
1.605g
1.605g-- (a) used in step 2
-Result of the calculation
Mass of NaHCO3 in the mixture
Mass of Na2CO3 in the mixture
1.070g –(b) = step4
0.930g
-Percentage of NaHCO3 of the sample = 53.50% --(c) = step 5
To figure out the percentage of NaHCO3 in the original mixture, one needs an equation.
In step1, one set up x as a mass of NaHCO3 in the original mixture. Thus, equation that shows that the total mass of NaHCO3 and Na2CO3 is 2.00g. In the second step, by using gravimetric analysis, one converts x into the mass of Na2CO3 that has been produced from heated NaHCO3, and states that the total mass of produced Na2CO3 and the Na2CO3 in the original mass is 1.605g, the result that the experimenter gained from the experiment. In the step4, one figures out the x, the mass of NaHCO3 is 1.070g. In step5, the percentage of NaHCO3 is being calculated by using the number that one gained from step4.
2NaHCO3(s) Na2CO3(s) + CO2(g) + H2O(g)
1) 2.00g = xg NaHCO3 + (2.00g –xg) Na2CO3
2) According to the equation above, xg NaHCO3 X (1mol NaHCO3/84.01g NaHCO3) X (1mol Na2CO3/2mol NaHCO3) X (105.99g Na2CO3/1mol Na2CO3) + (2.00g – xg NaHCO3) = 1.605g –(a)
3) 0.6308x + 2.00g – x = 1.605g
4) x = 1.070g NaHCO3 --(b)
5) %NaHCO3 = (1.070g/2.00g) X 100% = 53.50%
--(c)
4. Lab Review
-1- What is the quality of the science in the lab report?
Was the investigation conducted well?
Were sufficient trials run to instill confidence in the results reported?
Is there evidence that the data were collected carefully?
Yes. But one cannot be sure as the trial procedure is not clearly suggested.
Yes, the mixture was sufficiently heated, until its mass would not decrease anymore
No, as the procedure only says “heat mixture to a constant mass”, whether the experimenter or the creator of the lab report collected the data meticulously or not is not suggested. More detailed procedure will definitely show readers that the data suggested are carefully collected.
Are the explanations of chemistry in the lab report correct?
Yes, the picture of the equation correctly visualizes the process of the decomposition of NaHCO3. Though, little more explanation of the process itself would facilitate the understanding of the reader of the lab report.
Are the calculations done correctly?
Yes.
Does the report account for any problems in the investigation?
Yes, the conclusion says that the experimenter spilled some of the mixture few times and the balance might have been off.
-2- What is the quality of the reporting the scientist did the lab report?
Does the lab report communicate the investigation effectively?
Is the procedure detailed enough that it can be reported to verify the results?
Were the materials and equipment specified sufficiently?
Are the calculations presented clearly?
No, there is no any sufficient explanation about the process of the experiment itself. Also, the procedure is so simple and insufficient that readers might not be able to correctly execute the experiment. Though, mathematical processes in trial 1 and 2 aids readers to understand the method that is used to gain the mass of NaHCO3 in the mixture.
No, procedure only states “heat mixture to a constant mass”, which certainly isn’t a sufficient procedure to follow. Thus, if the reader attempts to do the same experiment, experimenter can make errors, as detailed procedure is not included or possibly reader might not even able to do the experiment as he or she might not know what to utilize and how to gain the desired result.
No, the materials and equipment required for the experiment is not specified at all.
Yes, but explanation of the process of the calculation in words would help the readers understand the process better.
Are any of the sections of the lab report weak, and how can they be strengthened?
For example: Is the procedure clear? Are the data reported effectively?
The purpose of the lab is not suggested; only the goal of experiment is stated without any sufficient explanation why this experiment is important, such as theories or lessons that could be proven or gained by this experiment. Also, the procedure is so vague and short that it would cause the readers to not be able to follow or do the experiment due to the insufficient explanation or extremely simple procedure. Explanations about the calculations in words would’ve improved the lab a lot, as they would facilitate the understanding of the reader. Though, the data is effectively reported by the given chart.
-3- How green is the chemical process that is reported?
What is the atom economy of the chemical reaction?
To calculate this, you must identify the desired product.
Show your calculation.
The desired product is Na2CO3, as the that is the only product that is able to obtain without any tools to collect gas state substances like carbon dioxide and water (and the tools were not required), and the goal of the lab is to turn bicarbonate into carbonate so as to know the mass of NaHCO3 in the mixture by figuring out the mass of water and carbon dioxide.
The atom economy is
Equation: (105.98g/168.14g) X 100 = 63.030%
** additional data**
Trial1: 4.473g – 3.836g = 0.637g = original amount of Na 2CO3 in the mixture. Thus, 3.057g – 0.637g = 2.42g of Na2CO3 was created from decomposition of Na2CO3.
As the original amount of NaHCO3 is 3.836g, the atom economy is (2.42g/3.836g) X 100 = 63.1%
Trial2: Using the same way
(3.322/5.267g) X 100 = 63.072%
Provide an argument based on a different principle of Green Chemistry for or against the “greenness” of the chemical process reported in the lab report.
As the rest of the products except Na2CO3 is water and carbon dioxide, it could be said that this experiment is quite green; the product is not toxic and biodegradable. Though, CO2 could negatively affect the nature, but not in a significant degree. Also, as the rest of products are just going to evaporate without any harm to the environment, a fact that shows that there is no disposal problem, the experiment technically leaves no waste even though the atom economy is only 63.1%. In essence, as the experiment leaves no waste, the products are not toxic, the products do not harm humans or environment significantly, the only energy needed is heat, and the products are biodegradable and mostly environmentally friendly, this experiment is quite green. Though, it is true that CO2 could have some negative influence towards environment, but it is not significant.
5. Post-Lab
(1)
MgSO4*xH2O(s) -> MgSO4(s) + xH2O(g)
a. 3.648g – 1.782g = 1.866g
1.866g H2O
1.866gH2O X (1mol H2O/[2(1.008g)+16g]) = 0.1036mol H2O
1.782g MgSO4 X (1mol MgSO4/120.3683g) = 0.01480mol MgSO4
0.1036 / 0.01480 = 7
Thus the ratio is 1:7
b. [120.4/(7(18.02)+120.4)]X100 = 48%
(2)
Process A =
C6H16N + OH- -(+heat) C3H6 + N(CH3)3 + H2O
Process B=
CH3CH2CH2OH (+heat+H2SO4) C3H6 + H2O
Process A= (42.078/119.206) X 100 = 35.299%
Process B=(42.078/60.094) X 100 = 70.020%
According to the atom economy, process B generates relatively more desired products. In fact, process B is twice efficient if only the ratio of amount of reactants and the desired product is considered. Also, process B actually can be regarded as a process that leaves no waste, as the only byproduct is water.
6. Citation
Editor: Smith, Jennifer, Chemistry AP lab worksheet. “Stoichiometry”
Mercersburg Academy, Pennsylvania.
The following experiments followed the instructions of “Types of Reactions lab” created by Jennifer Smith, a Chemistry AP teacher in Mercersburg Academy.
"Chemical Reactions and Stoichiometry." The Concord Consortium. N.p., n.d. Web. 07 Nov. 2013.
"Resource Type: Virtual Labs." ChemCollective: Virtual Labs. N.p., n.d. Web. 07 Nov. 2013.
Lab Report: Stoichiometry Lab
1. Prelab
Part1.
1) Create no waste = The principle that encourages chemists to not create waste at the first place rather than cleaning it up afterwards effectively shifts the chemistry more environmentally conscious, as creating no waste would make the experiment efficient; the reactants will be reduced to only the essential ones and the product will be maximized, a change that would make the experiment economic. Also, if chemists aim to engender no waste, this principle would solve the problem of disposal; as waste is often disposed by throwing it away in the nature, less waste possible will inflict less harm to the environment. Also, sometimes, the left over from the experiment …show more content…
causes disposal problems, as the experiments creates wastes that are hard to eliminate such as those with toxicity. For instance, during drug manufacturing, it often coproduces 100kilograms of waste for 100 kilogram of the desired product; however, if the green principle is applied, the waste can be reduced to 1/10. Thus, when choosing from two possible chemical processes chemists should consider preferring one that leaves less waste over the others, as leaving no waste contributes tremendously to environmentally conscious experiments.
2) 127.092g Cu/171.103g Reactants X 100 = 71.27%
63.546g Cu/95.546g Reactants X 100 = 66.50%
3) (a) the first process
(b) Atom economy informs the experimenters about the efficiency and economical aspect of the experiment. As high atom economy indicates that the experiment created more desired product and less waste, a indication of a green experiment. Thus, according to the principles of green chemistry, as the experiment with high atom economy creates less waste, makes the energy usage efficient, and gets rid of all nonessential additives( reducing non-essential reactants), a process with the high atom economy means that it is greener than other experiments. In essence, an experiment with high atom economy leads people to not waste any atoms; thus, people will utilize the rare and scarce resources more efficiently, and reduces the amount of waste that could harm the environment.
(c) The principle of using materials that break down in the environment also effectively leads the experiments to be greener, as left over reactants would not cause any disposal problems. Also, if the experiment yields biodegradable products from environmentally friendly reactants, this would also eliminate the concern of disposal problem such as waste of energy for disposing unsafe materials and would create smaller amount of toxic products. Also, biodegradable products will decrease the exposure of inherently dangerous chemicals to other animals or plants.
4) Peer review is crucial part of experiments.
Peer review is a process of rendering other people with the knowledge of the subject to check the process and the result that the experimenter has yielded. Thus, receiving peer reviews before publication is significant, as peers with different perspectives can point out and inform the experiments about the errors, any possible source of obfuscation, misleading parts and parts that the experimenter might have not considered. It also generally increases the quality of the report after the discussion with peers. Thus, chemists whose process could be propagated and could be used by others, wrong instructions could lead people to cause mistakes, and dangerous accidents. Thus, to reduce those risks, peer review could offer great benefits of making the experiments more secure. In essence, the results without any peer reviews has a higher chance of containing errors, a phenomenon that should be prevented before reporting the results of chemical …show more content…
process.
Part2.
CuSO 4-xH2O (s) -> CuSO4(s) + xH2O(g)
Initial mass: 0.1457g
Final mass: 0.0931g
0.1457g – 0.0931g = 0.0526g
0.0526g/0.1457g = 36.10% H2O
0.1457g X 63.9% = 0.0931g CuSO 4
0.0931g CuSO 4 X (1mol CuSO 4/63.546g+32.06g+64g) = 0.000583 mol CuSO 4
0.0526g H 2O X (1mol H2O/( 2(1.008g)+16g))= 0.00292 mol H2O
0.00292 mol H2O / 0.000583 CuSO4 =5.00
Thus, there is 5H2O
1) Chemical substance is a form of matter that has definite chemical composition and properties. It cannot be separated into smaller components without the chemical reaction that break the bonds.
Mixture is a combination of few different substances which are mixed physically but not chemically bonded.
Mixture is a combination of substances, like pebbles and dirt in water, but they still retain their own chemical compositions and did not react with each other chemically.
2) Separation of mixtures is often done based on chemical properties or physical properties like size, shape, mass, density, adsorption, solubility, volatility or chemical affinity between the components of the mixture.
3) The two methods of calculating the efficiency of a reaction, percent yield and atom economy, is same in the aspect that high number of both equations indicate that the product is generated economically and efficiently, reducing the waste as much as possible and maximizing the desired product. On the other hand, percent yield calculates the efficiency of the experiment while atom economy calculates the efficiency of the equations. In other words, percent yield shows how close the actual yielded result in real experiment is to the ideal result and atom economy shows which equations or processes will generate more desired products efficiently in an ideal condition.
2. Procedure
Materials:
Mixture of NaHCO3 and Na2CO3 with unknown ratio
Crucibles
Analytical balance
Clay triangle
Ring stands
Bunsen burner
[1] Weigh the crucible
[2] By using the analytical balance, put 2.00g of the mixture into the crucible
[3] Put the Clay triangle on the ring stand, and then ignite the fire of Bunsen burner.
[4] Heat the crucible for 2 minutes, turn the fire off and cool it down for 1minute and 30 seconds.
[5] Weigh the mass with analytical balance, and record the decreased amount of mass
[6] Repeat the step [4] and [5], until mass would not reduce after the mixture is heated.
[7] Record the mass of the ultimate result, subtract the mass of crucible from the result and then figure out the amount of evaporated H2O and CO2.
3. Data and Results
-Result of the experiment
Mass of the mixture before Heating
Mass of the mixture after 1ST heating
Mass after 2nd heating
Mass after 3rd heating
Mass after 4th heating
2.00g
1.611g
1.607g
1.605g
1.605g-- (a) used in step 2
-Result of the calculation
Mass of NaHCO3 in the mixture
Mass of Na2CO3 in the mixture
1.070g –(b) = step4
0.930g
-Percentage of NaHCO3 of the sample = 53.50% --(c) = step 5
To figure out the percentage of NaHCO3 in the original mixture, one needs an equation.
In step1, one set up x as a mass of NaHCO3 in the original mixture. Thus, equation that shows that the total mass of NaHCO3 and Na2CO3 is 2.00g. In the second step, by using gravimetric analysis, one converts x into the mass of Na2CO3 that has been produced from heated NaHCO3, and states that the total mass of produced Na2CO3 and the Na2CO3 in the original mass is 1.605g, the result that the experimenter gained from the experiment. In the step4, one figures out the x, the mass of NaHCO3 is 1.070g. In step5, the percentage of NaHCO3 is being calculated by using the number that one gained from step4.
2NaHCO3(s) Na2CO3(s) + CO2(g) + H2O(g)
1) 2.00g = xg NaHCO3 + (2.00g –xg) Na2CO3
2) According to the equation above, xg NaHCO3 X (1mol NaHCO3/84.01g NaHCO3) X (1mol Na2CO3/2mol NaHCO3) X (105.99g Na2CO3/1mol Na2CO3) + (2.00g – xg NaHCO3) = 1.605g –(a)
3) 0.6308x + 2.00g – x = 1.605g
4) x = 1.070g NaHCO3 --(b)
5) %NaHCO3 = (1.070g/2.00g) X 100% = 53.50%
--(c)
4. Lab Review
-1- What is the quality of the science in the lab report?
Was the investigation conducted well?
Were sufficient trials run to instill confidence in the results reported?
Is there evidence that the data were collected carefully?
Yes. But one cannot be sure as the trial procedure is not clearly suggested.
Yes, the mixture was sufficiently heated, until its mass would not decrease anymore
No, as the procedure only says “heat mixture to a constant mass”, whether the experimenter or the creator of the lab report collected the data meticulously or not is not suggested. More detailed procedure will definitely show readers that the data suggested are carefully collected.
Are the explanations of chemistry in the lab report correct?
Yes, the picture of the equation correctly visualizes the process of the decomposition of NaHCO3. Though, little more explanation of the process itself would facilitate the understanding of the reader of the lab report.
Are the calculations done correctly?
Yes.
Does the report account for any problems in the investigation?
Yes, the conclusion says that the experimenter spilled some of the mixture few times and the balance might have been off.
-2- What is the quality of the reporting the scientist did the lab report?
Does the lab report communicate the investigation effectively?
Is the procedure detailed enough that it can be reported to verify the results?
Were the materials and equipment specified sufficiently?
Are the calculations presented clearly?
No, there is no any sufficient explanation about the process of the experiment itself. Also, the procedure is so simple and insufficient that readers might not be able to correctly execute the experiment. Though, mathematical processes in trial 1 and 2 aids readers to understand the method that is used to gain the mass of NaHCO3 in the mixture.
No, procedure only states “heat mixture to a constant mass”, which certainly isn’t a sufficient procedure to follow. Thus, if the reader attempts to do the same experiment, experimenter can make errors, as detailed procedure is not included or possibly reader might not even able to do the experiment as he or she might not know what to utilize and how to gain the desired result.
No, the materials and equipment required for the experiment is not specified at all.
Yes, but explanation of the process of the calculation in words would help the readers understand the process better.
Are any of the sections of the lab report weak, and how can they be strengthened?
For example: Is the procedure clear? Are the data reported effectively?
The purpose of the lab is not suggested; only the goal of experiment is stated without any sufficient explanation why this experiment is important, such as theories or lessons that could be proven or gained by this experiment. Also, the procedure is so vague and short that it would cause the readers to not be able to follow or do the experiment due to the insufficient explanation or extremely simple procedure. Explanations about the calculations in words would’ve improved the lab a lot, as they would facilitate the understanding of the reader. Though, the data is effectively reported by the given chart.
-3- How green is the chemical process that is reported?
What is the atom economy of the chemical reaction?
To calculate this, you must identify the desired product.
Show your calculation.
The desired product is Na2CO3, as the that is the only product that is able to obtain without any tools to collect gas state substances like carbon dioxide and water (and the tools were not required), and the goal of the lab is to turn bicarbonate into carbonate so as to know the mass of NaHCO3 in the mixture by figuring out the mass of water and carbon dioxide.
The atom economy is
Equation: (105.98g/168.14g) X 100 = 63.030%
** additional data**
Trial1: 4.473g – 3.836g = 0.637g = original amount of Na 2CO3 in the mixture. Thus, 3.057g – 0.637g = 2.42g of Na2CO3 was created from decomposition of Na2CO3.
As the original amount of NaHCO3 is 3.836g, the atom economy is (2.42g/3.836g) X 100 = 63.1%
Trial2: Using the same way
(3.322/5.267g) X 100 = 63.072%
Provide an argument based on a different principle of Green Chemistry for or against the “greenness” of the chemical process reported in the lab report.
As the rest of the products except Na2CO3 is water and carbon dioxide, it could be said that this experiment is quite green; the product is not toxic and biodegradable. Though, CO2 could negatively affect the nature, but not in a significant degree. Also, as the rest of products are just going to evaporate without any harm to the environment, a fact that shows that there is no disposal problem, the experiment technically leaves no waste even though the atom economy is only 63.1%. In essence, as the experiment leaves no waste, the products are not toxic, the products do not harm humans or environment significantly, the only energy needed is heat, and the products are biodegradable and mostly environmentally friendly, this experiment is quite green. Though, it is true that CO2 could have some negative influence towards environment, but it is not significant.
5. Post-Lab
(1)
MgSO4*xH2O(s) -> MgSO4(s) + xH2O(g)
a. 3.648g – 1.782g = 1.866g
1.866g H2O
1.866gH2O X (1mol H2O/[2(1.008g)+16g]) = 0.1036mol H2O
1.782g MgSO4 X (1mol MgSO4/120.3683g) = 0.01480mol MgSO4
0.1036 / 0.01480 = 7
Thus the ratio is 1:7
b. [120.4/(7(18.02)+120.4)]X100 = 48%
(2)
Process A =
C6H16N + OH- -(+heat) C3H6 + N(CH3)3 + H2O
Process B=
CH3CH2CH2OH (+heat+H2SO4) C3H6 + H2O
Process A= (42.078/119.206) X 100 = 35.299%
Process B=(42.078/60.094) X 100 = 70.020%
According to the atom economy, process B generates relatively more desired products. In fact, process B is twice efficient if only the ratio of amount of reactants and the desired product is considered. Also, process B actually can be regarded as a process that leaves no waste, as the only byproduct is water.
6. Citation
Editor: Smith, Jennifer, Chemistry AP lab worksheet. “Stoichiometry”
Mercersburg Academy, Pennsylvania.
The following experiments followed the instructions of “Types of Reactions lab” created by Jennifer Smith, a Chemistry AP teacher in Mercersburg Academy.
"Chemical Reactions and Stoichiometry." The Concord Consortium. N.p., n.d. Web. 07 Nov. 2013.
"Resource Type: Virtual Labs." ChemCollective: Virtual Labs. N.p., n.d. Web. 07 Nov. 2013.