Question

What is the reaction energy Q of this reaction? Use c2=931.5MeV/u. Express your answer in millions of electron volts to three significant figures. View Available Hint(s) QQ Q = nothing MeV Part B Using fission, what mass m of uranium-235 would be necessary to supply all of the energy that the United States uses in a year, roughly 1.0×1019J? Express your answer in kilograms to two significant figures.

Answer 1

To calculate the reaction energy Q, use the formula Q = (mass difference) * c². To find the mass of uranium-235 needed to supply the energy used by the United States in a year, divide the given energy by the energy released per fission reaction of uranium-235.

Step-by-step explanation:

To calculate the reaction energy Q, we can use the formula Q = (mass difference) * c², where c is the speed of light. Given that c² = 931.5 MeV/u, we can calculate the energy in MeV. The mass difference for a reaction is usually given in atomic mass units (u). To convert u to kg, we need to divide by Avogadro's number and then multiply by the molar mass in kg.

To calculate the mass of uranium-235 needed to supply the energy used by the United States in a year, we need to divide the given energy (1.0 x 10^19 J) by the energy released per fission reaction of uranium-235 (200 MeV) and convert the result to kilograms.

Answer 2

Energy= 2.7758 × 10^-11 J ;

71.112×10^-6 kJ.

Mass defect in Kilogram= 3.0885×10^-28 kg.

That is; 3.1×10^-28 kg(to two significant figure).

Step-by-step explanation:

(Note: Check equation of reaction in the attached file/picture).

STEP ONE: we have to calculate the Mass defect.

Mass defect= Mass of reactants -- Mass of products.

Mass of the products: (140.9144+91.9262+3.060) u.

= 235.8666 u.

Mass of reactants: (1.0087+235.0439) u= 236.0526 u.

Therefore, the Mass defect= (236.0526 -- 235.8666) u

= 0.1860 u.

STEP TWO: Converting the Mass defect to energy;

0.18860 × 1.6605 × 10^27 kg

= 3.0885× 10^-28 kg

STEP THREE: Calculating energy released . Recall(from the question) c^2= 931.5 Mev/u. This is also equals to 9×10^16 m/s.

E=Mc^2.

Where E= energy released, c= speed of light, M= Mass.

Slotting in the values;

E= 3.0885×10^-28 kg × 9×10^16 m/s.

E=2.7758 × 10^-11 J.

Know that;( 1g of uranium × 1 mol of uranium ÷ 235.0439 g of uranium) × (6.002×10^23 atom of uranium/ 1 mol of uranium) × 2.7758× 10^-11.

=7.1112×10^-10 J

= 71.112×10^6 kJ.