PENENTUAN MASSA MOLAR BEBERAPA JENIS LOGAM MENGGUNAKAN HUKUM DULONG-PETIT

Abstract

The research about molar mass of some metals using calorimeter and Dulong-Petit’s law has been done. The metals used are Aluminium, Iron, Brass and Copper organized in a cubic form with mass of 2.79 g, 7.51 g, 8.38 g and 8.63 g respectively. The measurement of the heat capacity of calorimeter was conducted first as many as 7 times in order to include in the specific heat capacity. The specific heat capacity measurement of the metals was conducted first as many as 10 times for each metal. Molar mass of metals is then calculated using the specific heat capacity and law of Dulong-Petit. Research data shows that the temperature change of the water in calorimeter decreases overtime until it reaches the equilibrium while the temperature change of the metal and water mixture in the calorimeter increases overtime until it reaches the equilibrium temperature. Heat capacity of calorimeter measured is 67.35 J/0C. Specific heat capacities for metals Aluminium, Iron, Brass and Copper are 0.90 J/g0C, 0.47 J/g0C, 0.39 J/g0C and 0.38 J/g0C respectively. Calculation of the molar mass using the specific heat capacity and the law of Dulong-Petit are 27.96 g/mol, 53.53 g/mol, 64.54 g/mol and 66.40 g/mol respectively. Compared to the mass molar metal written on the Chemical Periodic Table, these discrepancies were found of 3.63% for Aluminium, 4.15% for Iron, and 1.58% for Copper.