Thermo-Chemistry

1. Thermo-Chemistry Group 3: Double X

2. Overall Group Consensus First Half of Thermo-Chemistry Questions: How is an isolated system created? It seems that it would be difficult to halt energy flow between a system and its surroundings. With regards to open and closed systems, would a system still be considered closed if the only the volume of the area increased, for example in like a piston? How do you determine energy flow if the pressure or volume isn't constant? • Enthalpy is a state function of internal energy, constant pressure and constant volume that helps us determine the flow of energy in a reaction. If the change in enthalpy is positive, the system gained heat from its surroundings, so system endothermic. If the change in enthalpy is negative, the system lost heat to its surroundings, so the system is exothermic. • Kinetic energy is the energy involved with movement and potential energy is the energy stored leading up to a movement. • Endothermic enters system exits solution and exothermic exits system enters solution. • First Law of Thermodynamics: The energy of the universe is constant, in other words, energy is neither created nor destroyed. • In an endergonic reaction, energy is gained from reaction whereas in an exergonic reaction, energy is lost to the surrounding.

3. Overall Group Consensus Second Half of Thermo-Chemistry Questions: How does multiplying the coefficient of a reaction change the delta H of a reaction? Why does the chemical reaction depend on the amount of matter? Does the standard enthalpy change of zero relates to thermodynamic energy, in that first law of thermodynamic stated energy cannot be destroyed nor created? If so where does delta h occur? Does enthalpy relate to Gibb's free energy in any way? • The change of H in the reaction is the change in H products minus the change in H reactants. • Hess's law states that if a reaction is carried out in a series of steps, delta H for the overall reaction reaction equals the sum of the enthalpy changes for the individual steps. • Because enthalpy is a state function, the enthalpy change, delta H, associated with any chemical reaction depends only on the amount of matter that undergoes change and on the the initial state of the reactants and the final state of the product.

4. Overall Group Consensus Thermo-Chemistry Questions: How is an isolated system created? It seems that it would be difficult to halt energy flow between a system and its surroundings. How do you determine energy flow if the pressure or volume isn't constant? Does enthalpy relate to Gibb's free energy in anyway? • If the change in enthalpy is positive, the system gained heat from its surroundings, so system endothermic. If the change in enthalpy is negative, the system lost heat to its surroundings, so the system is exothermic. • Endothermic enters system exits solution and exothermic exits system enters solution. • First Law of Thermodynamics: The energy of the universe is constant, in other words, energy is neither created nor destroyed. • Because enthalpy is a state function, the enthalpy change, delta H, associated with any chemical reaction depends only on the amount of matter that undergoes change and on the the initial state of the reactants and the final state of the product. • The change of H in the reaction is the change in H products minus the change in H reactants.