Use the References to access important values if needed for this question. In th

Question

Use the References to access important values if needed for this question. In the laboratory a "coffee cup" calorimeter, or constant pressure calorimeter, is frequently used to determine the specific heat of a solid, or to measure the energy of a solution phase reaction. A chunk of niekel weighing 18.15 grams and originally at 98.30 °C is dropped into an insulated cup coataining 83.83 grams of water at 20.42 °C The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.74 J°C. ted Using the accepted value for the specific heat of nickel (See the References tool), calculate the final temperature of the water. Assume that no heat is lost to the surroundings. Submit Answer Retry Entire Group 7 more group attempts remaining MacBook Air

Explanation / Answer

1) heat lost by metal(Ni) = heat gained by water

mass of metal(Ni)*s1*DT1 = mass of water*s2*DT2 + C*dT2

mass of metal(Ni) = 18.15 g

s1 = specific heat of metal(Ni) = 0.44 j/g.c

DT1 = 98.3-x

mass of water = 83.83 g

S2 = specific heat of water = 4.18 j/g.c

DT2 = x-20.42

C = Calorimeterconstant = 1.74 j/c

18.15*0.44*(98.3-x) = 83.83*4.184*(x-20.42)+1.74*(x-20.42)

x = final temperature = 22.145 C

2) heat liberated (q) = m*s*DT + C*dT

        m = mass of solution = 10.62+119.90 = 130.52 g

        s = specific heat of solution = 4.184 j/g.c

       DT = 25.76-22.81 = 2.95 c

       C = calorimeter constant = 1.64 j/c

   q = 130.52*4.184*2.95+1.64*2.95

     = 1.615 kj

no of mol of CsBr dissolved = w/Mwt

                          = 10.62/212.81

                          = 0.05 mol

DHsol = -q/n

       = -1.615/0.05

       = -32.3 kj/mol

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