Experimental measurements of heat capacities are often represented in reference works as empirical formulas. For graphite, a formula that works well over a fairly wide range of temperatures is (for one mole)
where a = 16.86 J/K, b = 4.77 × 10–3 J/K2, and c = 8.54 × 105 J.K. Suppose, then, that a mole of graphite is heated at constant pressure from 298 K to 500 K. Calculate the increase in its entropy during this process. Add on the tabulated value of S(298 K) (from the back of this book) to obtain S(500 K).
CEM 141 Lecture 26: Carbon and Graphite Dr. Jian Hu 2 November 2016 Bonding in Diamond Electron configuration is [He] 2s 2p 2 Carbon uses hybrid orbitals for bonding in diamond # of atomic orbitals in = # of hybrid orbitals out 1 s orbital + 3 p orbitals create 4 sp orbitals (sp hybridization) Each electron will occupy one of the sp orbitals sp naturally form a tetrahedral structure 3 When two carbon atoms (with sp ) combine, they form a sigma molecular orbital When the hybrid orbitals combine, there is a large gap between the bonding and antibonding molecular orbitals The sp hybridized atomic orbitals give rise to strong directed bonds (sigma bon