A 2.61 g sample of a substance suspected of being pure gold is warmed to 72.8 ∘C and submerged into 15.8 g of water initially at 24.9 ∘C. The final temperature of the mixture is 26.1 ∘C. What is the specific heat capacity of the unknown substance (in J/g*ºC) ?

Question

Chemistry

Priscilla Wolf

27 September, 20:20

A 2.61 g sample of a substance suspected of being pure gold is warmed to 72.8 ∘C and submerged into 15.8 g of water initially at 24.9 ∘C. The final temperature of the mixture is 26.1 ∘C. What is the specific heat capacity of the unknown substance (in J/g*ºC) ?

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Hannah · Answer 1

mg = 2.42 g

Tg = 72.2 deg. C

mw = 15.8 g

Tw = 24.5

Tf = 27 deg. C

Cw = 4.18 J/g. deg. C

Energy balance for insulated system,

ΔE = 0

ΔUw + ΔUg = 0

ΔUw = - ΔUg

Qin = Qout

mg*cg*ΔTg = mw*cw*ΔTw

2.42*cg * (72.2 - 27) = 15.8*4.18 * (27 - 24.5)

cg = 1.5095 J/g. deg. C or 1.5095 J/g. K