Question

Loren has the samples of elements that are listed below at room temperature. He exposes the samples to the same heat source until each sample reaches a temperature of 90.0°C.

10 g of Al(s) (C subscript p. = 0.897 J/(gi°C))
10 g of Ag(s) (C subscript p.= 0.234 J/gi°C )
10 g of Fe(s) (C subscript p. = 0.450 J/gi°C)
10 g of Zn(s) (C subscript p. = 0.387 J/gi°C )

From first to last, which lists the order in which these samples will reach 90.0°C?
Al, Fe, Zn, Ag
Ag, Zn, Fe, Al
Al, Fe, Ag, Zn
Ag, Al, Zn, Fe

Answer 1

Ag, Zn, Fe, Al

Reason: q = m Cp ΔT. With equal masses and same ΔT, the sample with the smallest Cp (Ag) needs the least heat and reaches 90.0°C first; the largest Cp (Al) takes the longest.