Question

ure of the object itself should not change. However, if a significant amount of heat flows from the object to speche heat capacey ofc-81SJ/(kg·C"), and a temperature of 12.0" С It is immersed ture will change. A thermometer has a mass of 36.0g, a and the final temperature of the water and thermometer is 41.29 C. What was the temperature of the water before t in 119 g of water, the insertion of the thermometer? (See Table 12.2 for appropriate constants.)

Answer 1

Given : M_t = 36 g or 0.036 kg , C_t = 815 J/kg°c , T_t = 12°c , M_w= 119 g or 0.119 kg , T_f = 41.2°c

Goal : Initial temperature of water (T_w)= ?

Constant : heat capacity of water (C_w)= 4186 J/kg°c

Solution:

According to the conservation of energy,

Heat loss by water = Heat gain by thermometer

M_wC_w(T_w-T_f) = M_tC_t(T_f-T_t)

(0.119)(4186)(T_w-41.2) = (0.036)(815)(41.2 - 12)

498.134(T_w-41.2) = 856.728

T_w - 41.2 = 1.72

T_w = 42.92°c

Answer : T_w = 42.92°c