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20 Cards in this Set
- Front
- Back
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What is thermodynamics?
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The science of heat and work. Its principles apply to energy use.
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What's energy?
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Energy is the capacity to do work.
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Kinetic energy? Potential energy?
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Kinetic energy is energy associated with motion. Potential energy is stored, and becomes kinetic upon movement.
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First law of thermodynamics?
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Energy can neither be created nor destroyed. It gets transfered.
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System? Surroundings?
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The system is what is being studied or observed. The surroundings includes anything that is outside of the system. This shows how heat is transfered.
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Thermal equilibrium?
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When two objects reach the same temperature. Heat always transfers from hot to cold.
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Different types of heat transfers.
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When the system takes in heat, it is endothermic, whereas when heat is released from the system, it's exothermic.
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Energy units?
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The SI unit for thermal energy is measured in joules. 1 J equals 1 kg*m^2/s^2 (similar to the units for pressure). One calorie = 4.184 joules.
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Specific heat capacity?
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The specific heat capacity is the quantity of heat required to raise the temperature of 1 gram of a substance by 1 kelvin. It is measured in J/g*K. This is used in energy equations.
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Formula to calculate the energy transfered of an object.
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q (heat) = C (specific capacity) * m (grams) * Change in T (kelvin)
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How to measure change in temperature?
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Change = Final T - Initial T
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Energy and change in state.
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Whenever an object changes in state (ie. Liquid to gas), energy is transfered during the process.
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Enthalpy?
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The heat content of a substance at constant pressure. ΔH. In equations, it's the same as q.
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Reaction changes and energy.
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If a chemical reaction is reversed, then the sign (+/-) of the energy is switched. Multipliers to the chemical reaction (ie. A+B->C to 2A+2B->2C) also applies to the reaction's energy.
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Entropy?
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Disorder of a reaction. Positive entropy = spontaneous, negative entropy = non-spontaneous. It is never 0, for that signifies that a reaction did not take place.
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Second law of thermodynamics?
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A spontaneous process is one that results in an increase of entropy in the universe.
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Third law of thermodynamics?
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Entropy is 0 when K = 0.
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General entropy question (that nobody uses).
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ΔS (universe) = ΔS (system) + ΔS (surroundings)
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Gibbs free energy?
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Denoted as G, it refers to the free energy in a chemical reaction. ΔG at negative means reaction is spontaneous. ΔG at positive means reaction is not spontaneous. ΔG at 0 means the reaction is at equalibrium.
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Gibbs free energy equation?
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ΔG = ΔH - TΔS.
ΔH = enthalpy T = Temperature in Kelvins ΔS = Entropy |
