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The following information is given for magnesium at 1 atm: boiling point = 1.090

ID: 534461 • Letter: T

Question

The following information is given for magnesium at 1 atm: boiling point = 1.090 times 10^3 degree C Delta H_vap(1.090 times 10^3 degree C) = 5.424 times 10^3 J/g melting point = 649.0 degree C Delta H_fus(649.0 degree C) = 368.3 J/g specific heat solid = 1.017 J/g degree C specific heat liquid = 1.339 J/g degree C A 34.10 g sample of solid magnesium is initially at 631.0 degree C. If 1.223 times 10^4 J of heat are added to the sample at constant pressure (P = 1 atm), which of the following are true. Choose all that apply. The sample is at a temperature of 649.0 degree C. The sample is at a temperature greater than 649.0 degree C. The sample is a solid. The sample is a solid in equilibrium with liquid. The sample is a liquid.

Explanation / Answer

Heat required to raise temp of Mg from 631 to 6490C = m*C*dT = 34.10*1.017*(649-631) = 624.2346 J

Net heat supplied = 12230 J

Heat remaining after raising temp to 6490C = 12230-624.2346 = 11605.7654 J

Heat required to melt Mg = m*L = 34.10*368.3 = 12559.03 J

Since this much heat is not available, so

the sample is a solid in equilibrium with the liquid.