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## Heat of reaction equations

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**Heat of reaction equations**Using simultaneous equations**Simultaneous equations**GIVEN: ΔH A + B = C -50 D + E = F +24 F + C = H ???**Simultaneous equations**GIVEN: ΔH A + B = C -50 D + E = F +24 F + C = A+ B + C + D ???**Simultaneous equations**GIVEN: ΔH A + B = C -50 D + E = F +24 A+ B + E + D= H -26**INTERPRETING DATA**• In any reaction, the heat taken in or given out is determined by the direction of the reaction. • Always work left to right ΔH A + B = C - 50**INTERPRETING DATA**• In any reaction, the heat taken in or given out is determined by the direction of the reaction. • Always work left to right ΔH A + B = C - 50 C = A + B ......**INTERPRETING DATA**• In any reaction, the heat taken in or given out is determined by the direction of the reaction. • Always work left to right ΔH A + B = C - 50 C = A + B +50**INTERPRETING DATA**• In any reaction, the heat taken in or given out is determined by the direction of the reaction. • Always work left to right ΔH A + B = C - 50 C = A + B +50 • If the direction of the reaction is reversed, the sign of the energy is changed (- to + or + to –)**Using this to solve an unknown reaction**• Q6(e) The combustion of Butene C4H8 is described by the following balanced equation. C4H8 + 6O2 4CO2 + 4H2O ΔH = –2710 kJ mol–1 The standard heats of formation of water and carbon dioxide are –286 and –394 kJ mol–1, respectively. Calculate the heat of formation of C4H8**What have we been told??**• Q6(e) The combustion of Butene C4H8 is described by the following balanced equation. • C4H8+ 6O2 4CO2 + 4H2O ΔH = –2710 kJ mol–1 This is the energy given out when butene is burned in oxygen**What have we been told??**• Q6(e) The combustion of one of Butene C4H8 is described by the following balanced equation. C4H8 + 6O2 4CO2 + 4H2O ΔH = –2710 kJ mol–1 The standard heats of formation of water and carbon dioxide are –286 and –394 kJ mol–1, respectively. Calculate the heat of formation of C4H8**What have we been told??**The standard heats of formation of water and carbon dioxide are –286 and –394 kJ mol–1, respectively. ΔH = kJ mol–1 H2 + ½O2 H2O -286 C + O2 CO2 -394**What do we need to know?**4C + 4H2C4H8 ΔH = ??? Using all the given info one has to manipulate the given formulas to leave the needed one. The question seeks to answer if the formation of butene is exothermic or endothermic**What’s next?**Write down all the info you have. ΔH = kJ mol–1 H2 + ½O2 H2O -286 C + O2 CO2 -394 C4H8 + 6O2 4CO2 + 4H2O –2710**What’s next?**Write down all the info you have. ΔH = kJ mol–1 H2 + ½O2 H2O -286 C + O2 CO2 -394 C4H8 + 6O2 4CO2 + 4H2O –2710 4C + 4H2C4H8 ΔH = ???**What’s next?**ΔH = kJ mol–1 H2 + ½O2 H2O -286 C + O2 CO2 -394 C4H8 + 6O2 4CO2 + 4H2O –2710 4C + 4H2C4H8 ΔH = ???**What’s next?**ΔH = kJ mol–1 H2 + ½O2 H2O -286 C + O2 CO2 -394 C4H8 + 6O2 4CO2 + 4H2O –2710 4CO2 + 4H2O C4H8 + 6O22710 reverse 4C + 4H2C4H8 ΔH = ???**What’s next?**ΔH = kJ mol–1 H2 + ½O2 H2O -286 C + O2 CO2 -394 C4H8 + 6O2 4CO2 + 4H2O –2710 4CO2 + 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 x4 4C + 4H2C4H8 ΔH = ???**What’s next?**ΔH = kJ mol–1 H2 + ½O2 H2O -286 C + O2 CO2 -394 C4H8 + 6O2 4CO2 + 4H2O –2710 4CO2 + 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144 x4 4C + 4H2C4H8 ΔH = ???**What’s next?**4C + 4H2C4H8 ΔH = ??? ΔH = kJ mol–1 4CO2 + 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144**What’s next?**4C + 4H2C4H8 ΔH = ??? ΔH = kJ mol–1 4CO2+ 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144**What’s next?**4C + 4H2C4H8 ΔH = ??? ΔH = kJ mol–1 4CO2+ 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144**What’s next?**4C + 4H2C4H8 ΔH = ??? ΔH = kJ mol–1 4CO2+ 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144**What’s next?**4C + 4H2C4H8 ΔH = ??? ΔH = kJ mol–1 4CO2+ 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144**What’s next?**4C + 4H2C4H8 ΔH = ??? ΔH = kJ mol–1 4CO2+ 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144**What’s next?**4C + 4H2C4H8 ΔH = ??? ΔH = kJ mol–1 4CO2+ 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144**What’s next?**4C + 4H2C4H8 ΔH = ??? ΔH = kJ mol–1 4CO2+ 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144 4C**What’s next?**4C + 4H2C4H8 ΔH = ??? ΔH = kJ mol–1 4CO2+ 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144 4C**What’s next?**4C + 4H2C4H8 ΔH = ??? ΔH = kJ mol–1 4CO2+ 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144 4C + 4H2**What’s next?**4C + 4H2C4H8 ΔH = ??? ΔH = kJ mol–1 4CO2+ 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144 4C + 4H2**What’s next?**4C + 4H2C4H8 ΔH = ??? ΔH = kJ mol–1 4CO2+ 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144 4C + 4H2 C4H8**What’s next?**4C + 4H2C4H8 ΔH = ??? ΔH = kJ mol–1 4CO2+ 4H2O C4H8 + 6O22710 4C + 4O2 4CO2 -1576 4H2 + 2O2 4H2O -1144 4C + 4H2 C4H8 -10