Question

(a) A student drops two metallic objects into a 120 g steel container holding 150 g of water at 25◦C. One object is a 200 g cube of copper that is initially at 85◦C, and the other is a chunk of aluminum that is initially at 5◦C. To the student’s surprise, the water reaches a final temperature of 25◦C, precisely where it started. What is the mass of the aluminum chunk? Specific heats of water, steel, copper, and aluminum are 4190J/kg ◦C, 420J/kg ◦C, 385J/kg ◦C, and 900J/kg ◦C, respectively.

(b) A 40 g block of ice is cooled to −78◦C. It is added to 560 g of water in an 80 g copper calorimeter at a temperature of 25◦C. Determine the final temperature. (If not all the ice melts, determine how much ice is left). Remember that the ice must first warm to 0◦C, melt, and then continue warming as water. The specific heat of ice is 0.5000 cal/g ◦C = 2.099 J/kg ◦C and latent heat of melting of ice is 3.33 × 105 J/kg.

Answer 1