Question

A chemist places a 100 g cube of each of the metals listed in the table on a separate hot plate. All of the hot plates are identical. Each hot plate is set on medium heat, and all of the cubes have the same initial temperature. Based on the specific heat values in the table, rank the metals in terms of how quickly they will reach the target temperature of 80°C. Use "1" to indicate the fastest and "5" to indicate the slowest.

Answer 1

The lower the specific heat the faster the temperaature will change.


You can learn it from the formula:


Q = m * Cs * ΔT


You can solve for ΔT


ΔT = Q / ( m * Cs)


Given the heat (Q) and m (100 g) are equal for the five samples:


 ΔT = [Q / m] / Cs. = constat / Cs


So you see the inverse relation between the change of temperatura and the specific heat.


So, the order of change of temperature is given by the specific heat: the lower the specific heat the faster the change of temperature. 


With that analysis you can calculate the order in which the cubes will reach the target temperature.

Answer 2

The answer is

Fe: 4

Al: 5

Cu: 3

Sn: 2

Pb: 1