Burns produced by steam at 100°C are much more severe than those produced by the

Question

Burns produced by steam at 100°C are much more severe than those produced by the same mass of 100°C water. To verify this, answer the questions below. Specific heat of water = 1.00 kcal/(kg · °C); heat of vaporization = 539 kcal/kg; specific heat of human flesh = 0.83 kcal/(kg · °C). (a) Calculate the quantity of heat that must be removed from 6.40 g of 100°C water to lower its temperature to 46.0°C. kcal (b) Calculate the quantity of heat that must be removed from 6.40 g of 100°C steam to condense it and lower its temperature to 46.0°C. kcal (c) Calculate the mass of human flesh that the quantity of heat produced in each case can raise from the normal 37.0°C to 46.0°C. (Flesh is badly damaged at 50.0°C.) water kg steam kg

Explanation / Answer

(a)
Q = m*c *dt
Q = 6.4 * 10^-3 * 1.0 Kcal * (100 - 46)
Q = 0.3456 Kcal.

(b)
Q = m*c *dt + m*Lv
Q = 6.4 * 10^-3 * 1.0 * (100 - 46) + 6.4*10^-3 * 539 Kcal
Q = 3.7952 Kcal.

(c)
In 1st case,
m1 * 0.83 * (46.0-37.0) = 0.3456
m1 = 0.0463 Kg
m1 = 46.3 g

In 2nd case,
m2 * 0.83 * (46.0-37.0) = 3.7952
m2 = 0.508 Kg
m2 = 508.1 g

Related Questions

Navigate

• Browse (All)
• Browse B
• Subjects

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