Exam 2
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)
CH6 Energy
The capacity to do work
CH6 Types of Energy (2)
Kinetic: the energy of motion Potential: stored energy
CH6 What is the form of energy that most other forms can be converted to?
Heat energy
CH6 What is heat energy measured in?
Calories
CH6 Calories
One calorie = heat energy required to raise the temp of 1 g of water 1 degree C 1 kilocalorie (kcal) = 1000 calories = 1 food calorie
CH6 How is potential energy, stored in chemical bonds, transferred from one molecule to another?
They are transferred by way of electrons
CH6 Redox Reactions
First, remember that redox comes from reduction-oxidation (reduction-gaining an electron; oxidation-losing an electron) This is both oxidation and reduction occurring at the same time These reactions are always coupled to one another
CH6 First Law of Thermodynamics
Energy cannot be created or destroyed, it can only be converted from one form to another Ex: sunlight energy –> chemical energy (through photosynthesis)
CH6 Second Law of Thermodynamics
Without external energy input, all systems naturally become more disorderly over time Ex: think of a room becoming messy over time-this seems to require zero energy, whereas cleaning it (making it orderly) requires work
CH6 Entropy
Disorder Written as “S”
CH6 Free Energy
The energy available to do work Written as “G” (Gibb’s Free Energy) Free energy = Enthalpy – (Temp X Entropy) G = H - TS
CH6 Enthalpy
Energy contained in a molecule’s chemical bonds
CH6 What effect do chemical reactions have on free energy?
Chemical reactions create changes in free energy ΔG = ΔH - T ΔS (Δ is the symbol “delta,” it represents a change)
CH6 In a chemical reaction, what happens when the products have MORE free energy than the reactants?
ΔG is positive (the change in free energy is a positive change); energy is gained
CH6 In a chemical reaction, what happens when the products contain LESS free energy than the reactants?
ΔG is negative (the change in free energy is negative); energy is lost
CH6 Endergonic Reaction
Requires free energy (positive ΔG) An “energy requiring” reaction *ender/enter ~ energy enters
CH6 Exergonic Reaction
releases free energy (negative ΔG) An “energy yielding” reaction *exo/exit ~ energy leaves
CH6 Activation Energy
Energy needed to get a reaction started by destabilizing chemical bonds *even exergonic reactions require some energy just to get started
CH6 Catalysts
Substances that lower the activation energy of a reaction
CH6 ATP
Adenosine triphosphate, the energy currency of the cells Structure: ribose (a 5-C sugar) adenine (a nucleotide) three phosphates
CH6 Where does ATP store energy?
In its phosphate bonds
CH6 Phosphates are highly _____
Phosphates are highly electronegative
CH6 What happens because of the electronegativity in phosphates? (What are some characteristics/properties they have due to their electronegativity?) (3)
They naturally repel each other Much energy is required to keep them bound to each other Much energy is released when the P bonds are broken
CH6 What happens when the bond between phosphates is broken by hydrolysis?
*First of all, hydrolysis is the chemical breakdown of a compound due to its reaction with water When this occurs, energy is released ATP = ADP + Pi