584 Heat and the First Law of ThermodynamicsP20.19Qmc Tm L==Cu CuNvapN22∆ej100293 7734800414....kg 0.092 0 cal g CCcal gkg⋅°−°==bgafmm*P20.20The original gravitational energy of the hailstone-Earth system changes entirely into additionalinternal energy in the hailstone, to produce its phase change. No temperature change occurs, eitherin the hailstone, in the air, or in sidewalk. ThenmgymLyLg=×⋅FHGIKJ=×333 109811340 1054...Jkg±mskg m sJm222P20.21(a)Since the heat required to melt 250 g of ice at 0°C exceedsthe heat required to cool 600 g ofwater from 18°C to 0°C, the final temperature of the system (water + ice) must be 0°C.(b)Let mrepresent the mass of ice that melts before the system reaches equilibrium at 0°C.QQmLm cTmmfwwicoldhotC±Jkg±kg±Jkg CCCg, so the ice remainingggg=−° −×=−⋅°°−°−=03 33 100 6004186018 0
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This note was uploaded on 12/14/2011 for the course PHY 203 taught by Professor Staff during the Fall '11 term at Indiana State University .