Answer:
the specific heat of the unknown compound is [tex]c_u=0.412J/g \cdot C[/tex]
Explanation:
Generally the change in temperature of water is evaluated as
[tex]\Delta T = T_2 -T_1[/tex]
Substituting 16.1°C for [tex]T_1[/tex] and 27.4°C for [tex]T_2[/tex]
[tex]\Delta T = 27.4 - 16.1[/tex]
[tex]=11.3^oC[/tex]
Generally the change in temperature of unknown compound is evaluated as
[tex]\Delta T_u = T_3 -T_2[/tex]
Substituting 27.4°C for [tex]T_2[/tex] and 94.3°C for [tex]T_3[/tex]
[tex]\Delta T = 94.3 - 27.4[/tex]
[tex]=66.9^oC[/tex]
Since there is an increase in temperature then heat is gained by water and this can be evaluated as
[tex]H_w = mc_w \Delta T[/tex]
Substituting 179.1 g for m , 4.18 J/g.C for [tex]c_w[/tex](specific heat of water)
[tex]H_w = 4.18 * 179.1 * 11.3[/tex]
[tex]= 8459.6J[/tex]
Since there is a decrease in temperature then heat is lost by unknown compound and this can be evaluated as
[tex]H_u = m_uc_u \Delta T_u[/tex]
By conservation of energy law
Heat lost = Heat gained
Substituting 306.9 g for [tex]m_u[/tex] , 8459.6J for [tex]H_u[/tex]
[tex]8459.6 = 306.9 * c_u * 66.9[/tex]
Therefore [tex]c_u = \frac{8459.6}{308.9 *66.9}[/tex]
[tex]=0.412J/g \cdot C[/tex]
