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17 Cards in this Set
- Front
- Back
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Exothermic reaction |
A reaction in which heat is released from the system |
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Endothermic reaction |
A reaction in which heat is gained by the system |
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Breaking chemical bonds is... |
Endothermic |
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Activation energy |
The minimum amount of energy required by the reactants in order to form products |
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Standard conditions |
100 kPa 298 K 1 mol/dm3 |
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Enthalpy change of combustion |
Te exothermic Heat change which accompanies the complete combustion of one mile of a substance |
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Enthalpy change of combustion |
The change in energy when 1 mol of a substance is made from its elements in their normal states |
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Enthalpy change of formation of an element |
0 |
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Enthalpy change of neutralisation |
The exothermic heat change that accompanies the production of one mole of water when an acid reacts with a base or alkali |
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Why is experimental determination of Enthalpy change of combustion very inaccurate |
Incomplete combustion Loss of heat to surroundings |
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Explain average bond Enthalpy |
The endothermic heat change to break one mole of covalent bonds in gaseous molecules averaged over a range of molecules with that bond |
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Equation for calculating the Enthalpy change of the reaction using bond enthalpies |
Bonds broken- bonds made= change in Enthalpy |
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Hess' law |
The total Enthalpy change from reactants to products is the same independent of the route taken |
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Boltzmann distribution |
The distribution of energies of molecules at a particular temperature, often shown as a graph |
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Area under curve (Boltzmann) |
Equal to the total number of molecules in the sample. AREA DOES NOT CHANGE with conditions |
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How many molecules in a system with zero energy? |
NONE |
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When drawing a Boltzmann curve why does it never touch the X axis |
Because there is no maximum energy for a molecule |
