Question

Part a:we can determine the purity of solid materials by using calorimetry. a gold ring (for pure gold, specific heat = 0.1291 j⋅g−1⋅k−1 ) with mass of 10.5 g is heated to 78.3 ∘c and immersed in 50 g of 23.7 ∘c water in a constant-pressure calorimeter. the final temperature of the water is 31.0 ∘c.

Answer 1

Thus, the question would probably ask if the ring of gold is actually pure gold. For this, first there is a need to calculate the specific heat capacity of the calorimeter. If this equivalent to the specific heat for pure gold, then the gold ring is pure fold.

Qwater = mCdt = (50 g) × (4.18 J/gC) (31 - 23.7) = 1525.7 J

On the basis of conservation of energy,

Qwater = Qcalorimeter = mCdT = 1525.7

1525.7 = (10.5) (C) (78.3 - 31)

C = 3.072 J/gC

As the specific heat of the calorimeter is not equivalent to that of the pure gold (0.1291 J/gC), then the gold ring is not pure.