Question

A chemist carefully measures the amount of heat needed to raise the temperature of a 1.98 kg sample of C4H1N from -2.5 °C to 16.2 °C. The experim shows that 9.72 x 10* J of heat are needed. What can the chemist report for the molar heat capacity of C H N ? Round your answer to 3 significant digi -1 -1 J. mol.K! x 6 ?

Answer 1

Heat Capacity ) is defined as the amount of Heat required to apply to a given a mass to increase it's tenperatere And the formula for Heat capacity is (ca mqoat / ma mass of sample Cg) q, heat supplied (I) ST Temperature change (K) Ginen ma 1.98 kg q z 9.72 x60" I oT a T₂-T, T, = initial temperature = -2.5°C+273 470.5 K erature a 16. 2°C + 273 = 2 89.2k AT = T, -T, 2 289.2 - 270.5 -118.7 K 7 a toto put in the formular; CoC 1.9867) (9.727/095 ] (18.7k) C> 1359.89 kg I KX/09 This is in units of kg Ik but the Answer we need to report in Imortit # calculate moles of 1.98 kg of GH, N. M artens - Molas mass y CGH, N = 4XC + 11xHAN z (4x/2) + (1/41)+14 56+11+ 14 = 81 g mole'

# moles z weight ar gram olan mars #moles a 1.980/000 g 81 g mol | #moles = 24.44 mole = 24.44 moles have capacity = 359.89*109 leg I k. 1 mole cheat capacity is » 359.894 104 for 24.44 7|14.728/0" Imole'k.! Again this cheat capacity is for 187 K Temperature change. for 118.7 k) Temperature chenye, heat capacity is 1 14.72x704 I molék for Ik Temperature change; 14.72x10" , a Imoletk 18.7 = 0.797810* J moletky 7.87 x 203 I moltkt / Answer is