A) A temperature difference of 45 K is maintained between the sides of a 2.1-cm

Question

A) A temperature difference of 45 K is maintained between the sides of a 2.1-cm thick slab of plywood. What is the rate of heat transfer through a 30-cm2 area of the slab? ___ W

A) A temperature difference of 45 K is maintained between the sides of a 2.1-cm thick slab of plywood. What is the rate of heat transfer through a 30-cm2 area of the slab? ___ W

A large pot is placed on a stove and 1.2 kg of water at 14°C is added to the pot. The temperature of the water is raised evenly to 100°C just before it starts to boil. (a) B) What amount of heat is absorbed by the water in reaching 100°C? (b) The water then boils until all of it has evaporated, turning to water vapor at 100°C. How much heat does the water absorb in this process?

  (a) _____  J
  (b) ______ J

Explanation / Answer

(A)

       Rate = k•A•(T1 - T2)/d

          = (0.13)(0.003)(45)/(0.021)      (0.13 W/m.K - Thermal Conductivity of Plywood)

      Rate = 0.8357 W

(B)

(a) water 14°C to water 100C

H = (1200)(4.181)(100 - 14)   (4.181 J/g/C = specific heat of water)

H = 431 479 J


(b) water 100C to vapor 100C

H = (1200)(2260)          (2260 J/g - heat of vaporization of water)

H = 2 712 000 J

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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