= in the change in Gibbs free energy equals the change ΔG ΔH – TΔS (Δ= change – in enthalpy minus the temperature times the change in entropy) Use the chart on p. 2 of the Laws of Thermodynamics to see that, for example, when the is positive and is positive, the chemical process will be spontaneous only at high ΔS ΔH temperatures. Carnot cycle a thermodynamic cycle that converts thermal energy into work the – – system goes through a series of different states and returns to the initial state work is – done on the surroundings study the diagram and the states on p. 3 of the Laws of – Thermodynamics Heat engine converts energy in the form of heat to mechanical work – Heat capacity the amount of heat required to raise the temperature of 1 g of a substance – 1 K (or 1 oC). molar heat capacity heat capacity /mol – specific heat capacity heat capacity/g x K or heat capacity/g x oC – Equation: = Cp x m x ΔH ΔT Cp = heat capacity (J/g K) x M = mass (g or Kg) T = temperature (oC or K) How many joules of heat are required to heat 100 g of aluminum from 20 K to 100 K? The heat capacity for aluminum is 0.908 J/gK. First we need to write down our given values. Cp=0.908 J/gK = 100 K 20 K = 80 K ΔT – Mass = 100 g The equation for calculation is: = Cp x m x ΔH ΔT. Then we substitute the values as follows:. = (0.908 J/gK) (100 g) x (80 K) ΔH = 7264 Joules. ΔH How much heat is required to heat 200 g of gold from 35 to 65 oC. The heat capacity of gold is 0.1291 j/gK? Cp = 0.1291 J/gK
ΔG = ΔH – TΔS (Δ= change in – the change in Gibbs free energy equals the change in enthalpy minus the temperature times the change in entropy) Use the chart on p. 2 of the Laws of Thermodynamics to see that, for example, when the ΔS is positive and ΔH is positive, the chemical process will be spontaneous only at high temperatures. Carnot cycle – a thermodynamic cycle that converts thermal energy into work – the system goes through a series of different states and returns to the initial state – work is done on the surroundings – study the diagram and the states on p. 3 of the Laws of Thermodynamics Heat engine – converts energy in the form of heat to mechanical work Heat capacity – the amount of heat required to raise the temperature of 1 g of a substance 1 K (or 1 oC). molar heat capacity – heat capacity /mol specific heat capacity – heat capacity/g x K or heat capacity/g x oC Equation: ΔH = Cp x m x ΔT Cp = heat capacity (J/g x K) M = mass (g or Kg) T = temperature (oC or K) How many joules of heat are required to heat 100 g of aluminum from 20 K to 100 K? The heat capacity for aluminum is 0.908 J/gK. First we need to write down our given values. Cp=0.908 J/gK ΔT = 100 K – 20 K = 80 K Mass = 100 g The equation for calculation is: ΔH = Cp x m x ΔT. Then we substitute the values as follows:. ΔH = (0.908 J/gK) (100 g) x (80 K) ΔH = 7264 Joules. How much heat is required to heat 200 g of gold from 35 to 65 oC. The heat capacity of gold is 0.1291 j/gK? Cp = 0.1291 J/gK
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