Question

Learning Goal: To understand specific heat and heat of transformation and how they are related to temperature versus time graphs Energy can be added to a system either by doing work w an it or by adding heat tot Energy transfer by work equires a force to act through some distance Energy ansfer in the form of heat occurs between objects that are different temperatures with onergy spontaneously aveling from the higher temperature object to the lower mperature one. When energy is added to an isolated stem in the form of heat, either the temperature of the em will increase or the system will undergo a phase ange at a fixed temperature Review Refer to the temperature versus time graph Figure 2 when aning the questions in Port Chrough stienos system original at T-210°C is placed in 250 kg of The the where nergy is removed from it in the form of heat t o the showshoe the temperature of the system takes 10 min-600 ste doo O Chorwich reware Oro the bring incom e temperature of the resulting ce continues to dropreaching temperatures an hour. The town heat and he was on values for water may be helt specific heat of leat O'C) - 2100 J/(kg ) heat of fusion (ce to waterphase change at 0°C) LE - 33410J/kg specific heat of water ( 15 ) C4186J/(kr K) heat of Vapozon water to steam phase change at 100' L210J/kg specific heat of steam (1100 2010 J/(kg ) specific heat of a sample characterizes the rate at chit changes temperature per un mess when I receives way in the form of heat. The relationship between the gy input in the form of heat and the resulting rature change AT Part to lower its temperature to 2 of 2 > How much y must be transferred out of the system as heat Express your answer numerically in joules. View Available Hints) Hint 1. How to approach the problem Decide whether this is a single phase changing temperature shuation or a single-temperature changing phase situation, then calcube accordingly using the equations from the introduction. Look up specific heats and/or heats of transformation for water in the table Temperature (°C) 190 AED ROO? 0 10 20 30 40 50 60 Time (min)

Answer 1

Q = amount of heat transferred out to lower the temperature to 0oC = msw(T-0oC) [m = mass, sw = specific heat capacity of water, T = initial temperature]

=> Q = 0.250 x 4186 x (21 - 0) = 21976.5 J [answer]