Thermodynamics

• The first law of thermodynamics states that energy cannot be created or destroyed, also known as conservation of energy.
• The surroundings are everything else in the system.
• Energy can be transferred from systems to surroundings, but it cannot be created or destroyed.
• The first form of energy that can be transferred is heat, represented by the letter Q.
• If heat is put into the system, the system will gain that heat and Q will be positive.
• If heat is transferred out, the system will lose that heat and Q will be negative.
• The system can gain or lose energy as a result of work, represented by the letter W.
• If the system gains work, it's positive and if it loses work, it's negative.
• The entropy of the universe increases for a spontaneous process, represented by the letter Delta S.
• The entropy of the system plus surroundings has to be positive for the entire universe to increase entropy.
• The third law of thermodynamics states that a perfect Crystal, represented by the letter T, at zero degrees Kelvin has zero entropy.
• Entropy is temperature dependent, so as temperature goes up, entropy goes up.
• When a substance cools down to the minimum point, its entropy is zero.
• Entropy is temperature dependent, so as temperature goes down, entropy decreases.
• Entropy is correlated with Randomness or disorder but it's not the same thing or equivalent to it.
• Entropy is related to the number of microstates, represented by the letter S.
• Microstates are the number of unique states that a system can exist in, with more microstates meaning more entropy.
• If a system has one microstate, the natural log of one is zero, resulting in zero entropy.
• Boltzmann's constant, represented by the letter K sub B, is used in the equation for entropy.
• The universal gas constant, represented by the letter R, is different from Boltzmann's constant as it is for the moles of a substance, while Boltzmann's constant is for an individual atom or molecule of a substance.
• When a substance cools down to zero Kelvin, it reaches its lowest possible energy state, which is related to entropy.
• In a crystal lattice structure, nine atoms being all identical with no movement gives us one microstate, resulting in zero entropy.
• Adding temperature to a crystal lattice structure causes the molecules to start vibrating, leading to more microstates and more entropy.
• Adding an impurity to a crystal lattice structure allows one atom to go in nine different positions, resulting in nine different microstates and more entropy.
• Mixtures have more entropy than pure substances.
• The numerator in the equation for entropy is the heat transferred for a reversible process divided by temperatures in kelvin.
• Solids have the least amount of entropy as they have the most order, while gases have the most entropy as they have the least order.
• The factors affecting entropy include phase (solid, liquid, gas), temperature, and volume.
• Solids have the most order and least amount of entropy, while gases have the least order and most entropy.
• The higher the temperature, the more entropy.
• The greater the volume, the more entropy.
• Entropy, represented by the letter 'S', is a measure of disorder or randomness in a system.
• The larger the volume, the more locations atoms and molecules could be in, leading to more microstates and more entropy.
• More moles of a substance also means more entropy.
• The number of particles in a system affects its entropy.
• More complex molecules result in more entropy.
• Gases have more entropy than any other phase.
• If the reactant goes from order to disorder, Delta s is positive.
• Complexity is a factor in predicting Delta s.
• If the solid in a system changes to a liquid, there is an increase in entropy.