The oxygen in the universe formed through nuclear fusion reactions in stars acco

Question

The oxygen in the universe formed through nuclear fusion reactions in stars according to the process given below. (a) What is the Q for the reaction? (b) If a star consists of a mixture of equal numbers of helium and carbon atoms, and if the total mass of the star is 4.0 times 10^30 kg helium, how much mass energy would be produced if all the helium and carbon react to form oxygen? (d) If the total power output of the star is 1.0 times 10^30 W, how many years would the helium to carbon fusion process last?

Explanation / Answer

a) Q value for a reaction is the amount of energy released by that reactio

Q = (mi-mf) c2 = (12+4.002603-15.994915) × 1.66 ×10-27 × (3×108)^2 = 1.15 × 10-12 J

b) Assumin total number of He and C atoms will be equal in that star.

The number of reactions that can happen in star = Total mass/(mass of C + mass of He)

N = 4×1030/[(12+4.002603)× 1.66 ×10-27] = 1.51×1056.

Total mass energy E = N ×1.15 × 10-12 J = 1.51×1056 × 1.15 × 10-12 J = 1.74×1044 J.

d) Total output power P = 1030 W. Then time t = E/W = 1.74×1044/1030 s =   5.53 million years.

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.