In the experiment of Investigating The Law Of Conservation Of Mass-Energy the difference in mass of products and the reactants had to be found.
Lab Written by: Niharika Baviriseaty
Lab members: Warda Baten
Sara Beski
Madison Breder
9/25/10 P-4
Investigating The Law Of Conservation Of Mass-Energy
Standard Equation:
Addition of two mass numbers along with uncertainty.
Question: Addition of mass of Compound A ± 0.01g + Compound B ± 0.01g = ?
Mass of compound A (BaCl2) = 5.54 ± 0.01g
Mass of compound B (CuSo4)) = 10.86 ± 0.01g
- Add both of the masses together or insert in this formula: Compound A ± 0.01g + Compound B ± 0.01g = ?
Mass of compound A (BaCl2) = 5.54 ± 0.01g
Mass of compound B (CuSo4)) = 10.86 ± 0.01g
5.54 ± 0.01g + 10.86 ± 0.01g = 16.4 g.
- To find the uncertainty in any type of addition or subtraction, you ...
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Mass of compound A (BaCl2) = 5.54 ± 0.01g
Mass of compound B (CuSo4)) = 10.86 ± 0.01g
- Add both of the masses together or insert in this formula: Compound A ± 0.01g + Compound B ± 0.01g = ?
Mass of compound A (BaCl2) = 5.54 ± 0.01g
Mass of compound B (CuSo4)) = 10.86 ± 0.01g
5.54 ± 0.01g + 10.86 ± 0.01g = 16.4 g.
- To find the uncertainty in any type of addition or subtraction, you just add both uncertainties of both numbers together.
Compound A uncertainty: ± 0.01g
Compound B uncertainty: ± 0.01g
Add both uncertainties: ±0.01 + ±0.01 = ±0.02
- Combine the mass of both compounds with uncertainty so the answer is 16.4 ± 0.02g.
Analysis:
2) I determined the difference between the mass of reactants and the mass of the products to be -0.75g ± 0.02g. The difference should be 0.00g ± 0.02g because in the conversation of mass, the mass is not destroyed or created. I suggest for this idea that we must have had made a mistake in the reading of the mass on the reading scale. If this mistake was avoided we might have gotten a closer reading to our approximation of the difference of mass to be 0 with an uncertainty of 0.02.
- In nuclear reactions, the measureable difference in mass of the reactants and the products is not the result of massing errors because in a nuclear fission some of the mass is turned into free neutrons that are turned into gamma rays. For an example: let’s take an example of nuclear fission where that happens, let’s say we have Uranium-235 and we add a neutron to it with some energy which creates Uranium-236. As you have given off energy, this makes the nucleus of Uranium-235 to split into Krytpton-92 and Barium-141. When you add the mass of Krypton-92 and Barium-141, you get a mass of 233. As we look at the reactants mass or Uranium which was 236. We see that we are missing 3 neutrons of mass; the three neutrons are given off as gamma rays.
235 92 U + 10n -→ 14456Ba + 9036Kr + 3 0 n
Conclusion
In the experiment of “Investigating The Law Of Conservation Of Mass-Energy” the difference in mass of products and the reactants had to be found. By the hypothesis of the difference in mass of products and reactants to be close to 0.00g with an uncertainty ± 0.01g. This was not true in the experiment as proven; we had a total mass of reactants to be 16.4 ± 0.02g and the total mass of products to be 17.57 ± 0.02g. The difference in mass of reactants and products was -0.75g ± 0.02g. In the next paragraph why the mass was disrupted will be answered.
The lack of accuracy of data is consistent with in any experiment but in this experiment, the hypothesis was proven wrong completely as it was not close to expected. The answer fro the lack of accuracy is because of the lack of reading in the mass of reactants and products. The balance scale used for this reading of mass might have been disrupted while processing this experiment. But the data had an uncertainty as every result will have some but even with the uncertainty, the accuracy is not even close. So in this experiment the point of accuracy and uncertainty was being understood.
To better prove this experiment, it would be a better effect to better measure the grams of how much compound A or compound B. To also read the balance scale would be a better improvement to the experiment or a better technology used one. In this experiment, the concept of conservation of mass was being understood. Conservation of mass is the mass of reactants and products is same number with some proven of uncertainty (± 0.01g). This effect of conservation of mass is similar to all products and reactants except nuclear reactions such as nuclear fission and nuclear fusion. In nuclear fission, there is a decrease in mass of products from reactants as some neutrons are given off as free energy. In nuclear fusion, the mass is increased of products as it takes more energy for the product to be made.