Calculating Energy from Nuclear Reactions

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Discussion Overview

The discussion revolves around calculating the energy evolved from a nuclear reaction involving radon-222, polonium, and helium. Participants are attempting to derive the energy per mole based on given molar masses and the mass-energy equivalence principle.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant presents a calculation for the energy evolved using the mass-energy equivalence formula ΔE = Δmc², providing molar masses for radon, polonium, and helium.
  • Another participant suggests checking the calculations, specifically pointing out an error related to the speed of light.
  • A subsequent reply acknowledges the mistake and provides a corrected value for ΔE, but seeks guidance on how to convert this energy into kJ per mole.
  • A participant introduces an unrelated analogy about pricing apples, which does not directly contribute to the nuclear energy calculation.
  • Another participant questions the definition of a Joule and prompts a check on the units used in the calculations.

Areas of Agreement / Disagreement

The discussion remains unresolved, with participants correcting each other’s calculations and seeking further clarification on how to proceed with the energy conversion, indicating a lack of consensus on the final answer.

Contextual Notes

There are limitations regarding the assumptions made in the calculations, particularly in the application of the mass-energy equivalence and the treatment of units. The discussion also reflects uncertainty in the conversion process from Joules to kJ per mole.

Who May Find This Useful

This discussion may be useful for students or individuals interested in nuclear physics, energy calculations, or those seeking to understand the application of mass-energy equivalence in practical scenarios.

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1. It has been found by experiment that the molar mass of the Rn nucleotide is 221.9703 g and that of the Po nucleotide is 217.9630 g. The molar mass of helium is 4.00150 g. Given this information, and the information from the class, calculate the energy evolved, in kJ, for the following nuclear reaction of 400.0 g of radon-222.

2. ΔE = Δmc^2 where c is speed of light

# of mol (n) = mass/molar mass


The Attempt at a Solution


Δm = 221.9703 - (217.9630 + 4.00150)
= 5.8 x 10^-3

ΔE = 5.8 x 10^-3 (3.0 x 10^8)
= 1740000 J

n = 400.0/ 221.9703
= 1.803 mol

How do I get the energy to be kJ/mol? My teacher said the answer should be ---- x 10^8 kJ.
 
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Check your math - you are off by c.
 
Oh yes sorry! I forgot to square c!

But then I ended up getting:
ΔE= 5.22 x 10^14

What do I do now with ΔE and the number of moles of radon to figure out the energy per mole in kJ?
 
If two apples cost $4, what is a price in dollars per apple?
 
Also, what is a Joule? Check your units.
 

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