Chemical Reactions, Equilibria, and Industrial Processes
Hess’s Law
If a reaction can be performed in several steps, whether real or theoretical, the total enthalpy change is equal to the sum of the enthalpy changes of these intermediate reactions.
Standard Enthalpy of Reaction
From standard enthalpies of formation.
From bond enthalpies.
Standard Entropy of Reaction
Free Energy
Spontaneous
Theories of Chemical Reactions
Collision Theory
For a chemical reaction to occur, reactants (atoms, molecules, or ions) must collide. Effective collisions require:
- Sufficient
Atomic Structure and Chemical Reactions
Atomic Structure
Dalton’s Atomic Theory and Its Demise
Dalton’s atomic theory proposed that matter consists of indivisible particles called atoms. However, the discovery of the electron, a subatomic particle, challenged this theory.
Cathode Rays and the Electron
Cathode rays exhibit specific properties:
- They travel in a straight line from the cathode to the anode, producing fluorescence upon hitting the tube walls.
- They behave like a negatively charged electric current, deflecting towards the positive
Polymer Chemistry, Ceramics, and Composite Materials
Polymer Chemistry
For obtaining a polymer in polymer chemistry, hundreds of thousands of molecules (monomers) are chemically bound. Homopolymers are obtained if the polymer chain is formed by the union of identical monomers. If the polymer chain is formed by the union of different monomers, copolymers are obtained.
Polycondensation: The chain growth occurs by chemical reaction between two functional groups, in most cases with the loss of a small molecule, such as water or hydrochloric acid.
Polyaddition:
Read MoreImprovised Detonators and Explosives Construction
Detonators of delay, also known as time detonators, are useful in various applications. Here are some examples:
Mecha Time
It is relatively simple to create time detonators using fuses for ignition. One common method involves cigarettes, which burn for approximately eight minutes. By determining the burn time of a cigarette, you can plan its use as a delay fuse.
A similar method uses a rolled paper tube filled with coal dust and a leaf. Powdered coal mixed with finely ground materials can also serve
Read MoreElements and Nuclear Reactions: A Deep Dive
Nuclear Fission
By bombarding uranium atoms with neutrons, the nuclei are broken. This break, called nuclear fission, releases large amounts of energy. This process also releases more neutrons, which can break more uranium nuclei, creating a continuous chain reaction.
Nuclear Power Plants
The heat released in nuclear fission is enormous. However, to harness this energy, the chain reaction must be controlled. This is done in nuclear power plants. Nuclear power generation has risks, such as accidents
Read MoreChemical Bonds: Formation, Types, and Properties
Chemical Bonds
Chemical bonds form between atoms to achieve greater stability, often attaining a noble gas electron configuration. Bonds can be homoatomic (same atom) or heteroatomic (different atoms).
Ionic Bonds
Ionic bonds form between metals and nonmetals. Nonmetals gain electrons to form anions, achieving the nearest noble gas configuration. Metals lose electrons, forming cations. Stoichiometry depends on anion and cation charges.
Covalent Bonds
Covalent bonds form between nonmetals. Atoms share
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