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solniwko [45]
3 years ago
8

179.1 g of water is in a Styrofoam calorimeter of negligible heat capacity. The initial T of the water is 16.1oC. After 306.9 g

of an unknown compound at 94.3oC is added, the equilibrium T is 27.4oC.
What is the specific heat of the unknown compound in J/(goC)?
Chemistry
1 answer:
taurus [48]3 years ago
4 0

Answer:

the specific heat of the unknown compound is c_u=0.412J/g \cdot C

Explanation:

Generally the change in temperature of water is evaluated as

                \Delta T = T_2 -T_1

Substituting 16.1°C for T_1 and 27.4°C for T_2

                \Delta T = 27.4 - 16.1

                       =11.3^oC

Generally the change in temperature of  unknown compound is evaluated as

                  \Delta T_u = T_3 -T_2

Substituting 27.4°C for T_2 and 94.3°C for T_3

                                    \Delta T = 94.3 - 27.4

                                           =66.9^oC

Since there is an increase in temperature then heat is gained by water and this can be evaluated as

               H_w = mc_w \Delta T

Substituting 179.1 g  for m , 4.18 J/g.C for c_w(specific heat of water)

             H_w = 4.18 * 179.1 * 11.3

                   = 8459.6J

Since there is a decrease in temperature then heat is lost by unknown compound and this can be evaluated as

                    H_u = m_uc_u \Delta T_u

By conservation of energy law

       Heat lost  = Heat gained  

Substituting 306.9 g  for m_u , 8459.6J for H_u

           8459.6 = 306.9 * c_u * 66.9

  Therefore     c_u = \frac{8459.6}{308.9 *66.9}

                           =0.412J/g \cdot C

                   

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