Lecture 1
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
卡片预览 (24 张)
What is energy? What is work?
ENERGY is the ability to do WORK. Work is defined as the DISTANCE moved against an opposing FORCE.
Equation for work?
FORCE X DISTANCE = WORK
What is the first law of thermodynamics?
Energy is constant cannot be created nor destroyed by any physical and chemical changes.
When will a reaction not occur?
• Not enough energy= ACTIVATION ENERGY 2. Orientation of collisions= Correct molecules have to collide with each other.
What is the ENTHALPY CHANGE OF REACTION (ΔH)?
The difference in the change in energy between bond energies of reactants and products.
What is ΔHo?
Heat RELEASED or ABSORBED during a chemical reaction at STANDARD conditions.
Equation for ΔHo?
∆Ho = HProducts – Hreactants
Can you measure the actual enthalpy of a substance?
NO- only measure enthalpy change.
What are the standard conditions of a element?
1 Atmosphere 25oC
What is the standard conditions of a compound?
Gaseous Substance= Pressure of 1 Atmosphere. Pure substance in solid/ liquid= State it would have at 1 Atmosphere. Substance in solution= Concentration of 1 M.
EXOTHERMIC REACTION: What happens to the products? What happens to heat? Example: Temperature of the system... ΔH?
Products contain LESS energy than reactants. Products more stable. Heat is RELEASED to the surroundings. Eg. Burning/ Respiration. The temperature of the system will be observed to INCREASE. ∆H is NEGATIVE for an exothermic reaction.
ENDOTHERMIC REACTION: What happens to the products? What happens to heat? Example: Temperature of the system... ΔH?
Products contain MORE energy than the reactants. Products less stable. Heat is TAKEN IN from the surroundings. E.g photosynthesis. Temperature of system will DECREASE. ∆H is POSITIVE for an endothermic reaction.
Is bond breaking endothermic/ exothermic?
ENDOTHERMIC
Is bond making endothermic/ exothermic?
EXOTHERMIC
What is entropy? Entropy Symbol?
ENTROPY measures the amount of energetic DISORDER in a system. S
Equation for Change in Entropy?
∆S = Sfinal - Sinitial
Equation of the total change in entropy?
∆Stotal = ∆Ssystem + ∆Ssurroundings
What is the second law of thermodynamics?
Entropy tends to a maximum.
List examples of increases in entropy:
SOLIDS MELTING LIQUIDS BOILING NUMBER OF MOLECULES INCREASING. IONIC SOLIDS DISSOLVE TEMPERATURE INCREASE
What is Gibbs Free Energy?
The energy from a reaction FREE to do WORK.
Equation for Gibbs Free Energy:
ΔG = ΔH – TΔS
What does ΔG have to be for the reaction to be spontaneous, energy needed to be inputted and for the system to be at equilibrium?
ΔG < 0 Reaction will be SPONTANEOUS. ΔG > 0 Reaction needs ENERGY INPUT to happen. ΔG = 0 The system is in EQUILIBRIUM.
What is an Exergonic Reaction?
ΔG NEGATIVE
What is an Endergonic Reaction?
ΔG POSITIVE