Question

Brewed coffee is often too hot to drink right away. you can cool it with an ice cube, but this dilutes it. or you can buy a device that will cool your coffee without dilution - a 150 g aluminum cylinder that you take from your freezer and place in a mug of hot coffee. part a if the cylinder is cooled to -20âc, a typical freezer temperature, and then dropped into a large cup of coffee (essentially water, with a mass of 500 g) at 85âc, what is the final temperature of the coffee?

Answer 1

In order to answer this question you need to know the specific heat of aluminum and water. The source below says 0.900 J/g K and 4.186 J/g K respectively. Let T be the final temperature to be found: (0.900 J/g K) x (270 g) x (T - (-20))K = (243T + 4860) J gained by the Al (4.186 J/g K) x (500 g) x (85 - T)K = (177905 - 2093T ) J lost by the coffee Set the two expressions for heat gained/lost equal to each other: 243T + 4860 = 177905 - 2093T Solve for T algebraically: T = 74.1 °C