MEASURING ENTHALPY CHANGES
{"Image DocumentName": "MEASURING ENTHALPY CHANGES", "Image ImageDescription": "Calorimetry involves the practical determination of enthalpy changes. usually involves heating (or cooling) known amounts of water. water is heated up reaction is EXOTHERMIC. water cools down reaction is ENDOTHERMIC. Calculation The energy required to change the temperature. of a substance can be calculated using... q = m x c x DT. where q = heat energy kJ. m = mass kg. c = Specific Heat Capacity kJ K -1 kg -1 [ water is 4.18 ] DT = change in temperature K. Example On complete combustion, 0.18g of hexane raised the temperature of. 100g water from 22\u00b0C to 47\u00b0C. Calculate its enthalpy of combustion. Heat absorbed by the water (q) = 0.1 x 4.18 x 25 = kJ. Moles of hexane burned = mass / Mr = 0.18 / 86 = Enthalpy change = heat energy / moles = / ANS = 5000 kJ mol -1.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}