Ideally, when a thermometer is used to measure the temperature of an object, the

Question

Ideally, when a thermometer is used to measure the temperature of an object, the temperature of the object itself should not change. However, if a significant amount of heat flows from the object to the thermometer, the temperature will change. A thermometer has a mass of 28.0 g, a specific heat capacity of c = 815 J/(kg · C°), and a temperature of 12.0° C. It is immersed in 119 g of water, and the final temperature of the water and thermometer is 40.9° C. What was the temperature of the water before the insertion of the thermometer? (See Table 12.2 for appropriate constants.)

Explanation / Answer

mt = mass of thermometer = 28 g = 0.028 kg

ct = specific heat of thermometer = 815 J/kgc

Tit = initial Temperature of thermometer = 12 c

mw = mass of water = 119 g = 0.119 kg

cw = specific heat of water = 4186 J/kgc

T = initial Temperature of water

Teq = equilibrium temperature = 40.9

using conservation of energy

heat lost by water = heat gained by thermometer

mw cw (T - 40.9) = mt ct (40.9 - Tit)

0.119 x 4186 (T - 40.9) = 0.028 x 815 (40.9 - 12 )

T = 42.22 C

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

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