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Published byDana Harris Modified over 8 years ago
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+ Chemical Energy
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+ Hmmm… Can you list 5 energy sources that do not directly produce carbon dioxide?
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+ Cellular Respiration C6H12O6 + 6O2 6CO2 + 6H2O What type of reaction does this look like? Where would energy go in this reaction?
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+ Fossil Fuels Why can fossil fuels be considered as a stored solar energy source?
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+ Types of Energy Kinetic Energy = energy of motion Thermal Energy = heat = movement of particles Potential Energy = stored
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+ Heat Heat = thermal = kinetic energy (using the definitions from the previous slide, explain to your partner how this could be)
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+ q = mc Δ t (heat formula) q = heat, kinetic energy (J or kJ) m = mass c = specific heat capacity – amount of energy involved in changing the temperature of 1g of a substance by 1 o C Δ t = change in temperature
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+ Think About THIS! If you are heating water and metal at the same temperature, which one will heat up faster? Why? How do we relate that to Heat Capacity?!
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+ EXOTHERMIC CHANGE System loses energy
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+ ENDOTHERMIC CHANGE System gains energy
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+ Example: Calculate the energy released when 250mL of water cools down from 98.0C to 25.0C. (c for water = 4.19J/g/C)
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+ Example 2: Calculate the heat capacity of a pot that water is heated in when the energy required to heat the 300gram pot from 12C to 112C is 11.7kJ.
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+ Remember: Endothermic reactions energy is ABSORBED (surroundings get cooler) Exothermic reaction energy is RELEASED (surroundings get warmer)
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+ Enthalpy Enthalpy involves only changes in POTENTIAL ENERGY changes in bond energy
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+ 3 types of enthalpy changes (Ep) phase change – intermolecular bonds (forces) chemical change – intramolecular bonds (ionic / covalent) nuclear change – protons and neutrons are altered
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+ For tomorrow… How can we relate HEAT or Thermal energy to ENTHALPY????
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