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21 Nuclear Chemistry Solutions to Exercises 4.3 S kg X 1.673 1 proton X 1000 1kg = 2.594 10³⁶ = 3 10³⁶ 21.82 1000 Mwatts 1 1 Mwatt 10⁶ watts 1 watt 1J X 1 3 10⁻¹¹ atom J 6.02214 10²³ atoms / X 235 1 mol g U 3600 1 hr S 24hr 1d 365 1 yr d X 100 40 (efficiency) = 1.03 X 10⁶ = 1x U/yr 21.83 2 10⁻¹² curies 3.7 10¹⁰ dis/s = 7.4 X 10⁻² = 7 10⁻² dis/s 7.4 75 10⁻² kg dis/s 8 dis 10⁻¹³ J X 1 1 10⁻² rad J/g X 3600 hr S 24 1d hr 365 d = 2.49 10⁻⁶ = 2 10⁻⁶ rad/yr 1 yr Recall that there are 10 rem/rad for alpha particles. 2.49 10⁻⁶ rad 10 rem = 2.49 X 10⁻⁵ = 2 10⁻⁵ rem/yr 1 yr 1 rad Integrative Exercises 21.84 Calculate the molar mass of that contains 29.6% ³⁶Cl. Atomic mass of the enhanced is 0.296(36.0) + 0.704(35.453) = 35.615 = 35.6. The molar mass of is then (22.99 + 35.615 + 64.00) = 122.605 = 122.6. Calculate N, the number of ³⁶Cl nuclei, the value of k in and the activity in dis/s. 53.8mg 1000 1g mg 122.605 1 mol g X 1 mol 1 mol Cl 6.022 mol 10²³ Cl Clatoms 29.6 36 Clatoms = 7.822 X 10¹⁹ = 7.82 10¹⁹ 36 atoms 100 Clatoms k = = 3.0 0.693 10⁵ yr 365 24 3600 S = 7.32 10⁻¹⁴ = 7.3 10⁻¹⁴ 1 yr rate = kN = (7.32 10⁻¹⁴ 10¹⁹ nuclei) = 5.729x 10⁶ = 5.7 10⁶ dis/s 21.85 Calculate the amount of energy produced by the nuclear fusion reaction, the enthalpy of combustion, of C₈H₁₈, and then the mass of C₈H₁₈ required. Am for the reaction 4 + 2 ie is: 4(1.00782) 4.00260 amu - 2(5.4858 10⁻⁴ amu) = 0.027583 = 0.02758 amu = = 0.027583 amu X 6.02214 1g 10²³ amu 1000 1kg (2.9979246 10⁸ m/s)² = 4.11654 = 4.117 J/4 ¹H nuclei 666