Notes, summaries, assignments, exams, and problems for Chemistry

Thompson: A Marxist Historian

Thompson was a historian with a Marxist background whose interest in radical political works sets him apart from other authors we studied. He, like Hoggart, followed culturalism, a perspective that stresses human agency, or the active production of culture and not its passive consumption. His book The Making of the English Working Class really embodies the term, since in it he traces the development of the English working class between 1780 and 1832, more or less the time encompassed by the Industrial Revolution. The book can be seen as a rescue operation of the members (especially radicals) of the working class lost in a history led by the deaths of monarchs, statesmen, military leaders, and politicians. These... Continue reading "The Making of the English Working Class: A Radical Perspective" »

Distillation Tower Dynamics and Heat Transfer

After changing a process variable, the tower will reflect this change from top to bottom slowly. Each tray of a tower has a different temperature and vapor pressure than any other tray in the tower.

Flooding occurs when the liquid flow in the downcomers and onto the trays is too high, or when the vapor flow is too high. Heat is removed from the tower when hot or warm overhead and bottom products exit the tower, and through leaks in insulation.

Approximately 85% of the distillation tower heat is supplied by the reboiler. Heat sources for a distillation tower include:

• Radiant heat
• Sparging
• Reboilers

Tray Design and Liquid Flow

A downcomer is a device that allows liquid to flow from one tray to another between... Continue reading "Distillation Tower Operations and Furnace Fundamentals" »

Alkali Metals

Lithium

• Lithium is harder than other alkali metals.
• It has higher melting and boiling points than other alkali metals.
• It is the least reactive alkali metal.
• It is a strong reducing agent compared to other alkali metals.
• It is the only alkali metal that forms its monoxide.
• It is not capable of forming solid hydrogen carbonates, unlike other alkali metals.
• It does not react with ethyne to form ethynide, while other alkali metals do.
• It reacts slowly with bromine compared to other alkali metals.
• It is the only alkali metal that reacts with nitrogen to give lithium nitride (Li₃N).

Alkaline Earth Metals

Beryllium

• Beryllium is harder than other members of its group.
• It has higher melting and boiling points than other members of its group.
• Its electronegativity

Furnace Operations and Combustion Principles

Gas burners and fuel oil burners are the two primary types of furnace burners. Furnaces usually operate with 0.5 - 2.0% excess oxygen to maintain efficiency. During the process, furnace fuel and incomplete combustion form carbon dioxide and water.

Safety and Air Supply in Furnaces

Flame monitors ensure that a flame is lit in the burner at all times when the fuel safety shutoff valves are open. Balanced draft furnaces are the type of furnaces that use two fans: one inducing flow out of the stack and the other feeding air to the burners. To ensure complete combustion, secondary air is supplied to the furnace.

Extraction and Mass Transfer Processes

When the extract mixture has reached a point at which it... Continue reading "Industrial Furnace, Extraction, and Reactor Operations" »

Heat vs. Enthalpy

Enthalpy is a property of a system, sometimes termed "heat content." It represents the system's internal energy (U) plus the product of pressure and volume (pV).

Heat is energy in transit, transferred between systems. Enthalpy (H) is a state function defining the system's state.

Hess's Law and Enthalpy

Hess's law states that the total enthalpy change for a multi-step reaction equals the sum of enthalpy changes for each individual step. This principle, grounded in the conservation of energy, allows for calculating ΔH even when direct measurement is impossible. It enables the determination of standard enthalpies of formation, useful for designing complex syntheses.

Enthalpy and Reaction Types

Enthalpy determines whether a reaction... Continue reading "Heat vs. Enthalpy, Hess's Law, Reaction Types, and Chemical Properties" »

^{Correction fluid is a white liquid. The organic solvent was originally used as an ingredient in the product. This solvent is readily absorbed by the lungs via inhalation. It has been replaced by a safer alternative for painting over mistakes. A brush (which was later replaced by a foam applicator) is attached to the cap, so when the bottle is closed, the brush is immersed in the fluid. When unscrewed, the brush is covered in liquid which is then painted over the mistake. However, it is still possible to see that the product has been used, and also the original content if the paper is held up to a light.}

Functions of Language

• Expresiva or emotiva: expresses feelings
• Funcion apelativa: incites the receiver
• Representativa: provides information
• Poetica

Chemical Energy and Molecular Bonds

Chemical energy is the energy associated with chemical bonds and intermolecular attraction. The chemical energy of a set of reacting substances changes since bonds break and form new bonds, creating new products.

We call the energy exchanged in the form of heat between a system containing a chemical reaction and its surroundings the heat of reaction.

Exothermic and Endothermic Reactions

• Exothermic Reaction: The energy of the reactants is greater than that of the products and has a negative sign (e.g., combustion). These reactions release chemical energy via heat.
• Endothermic Reaction: The energy in the system grows. The exchange of energy via heat goes from the surroundings toward the system, so the heat of reaction

•Animals, plants, fungi, and most protists depend on mitochondria for energy to grow and survive

•There are more than 100 known mitochondrial disorders (including Luft syndrome)

•Defective mitochondria also contribute to many age-related problems (including Alzheimer’s)

•Aerobic respiration

•Form of cellular respiration in eukaryotes and many prokaryotes

•Oxygen is a reactant in the ATP producing process

•Anaerobic respiration

•Form of cellular respiration in some prokaryotes

•A molecule other than oxygen, such as sulfate or nitrate, is used in the ATP-producing process

•Photosynthesis stores energy from sunlight in electron-rich fuel molecules (such as sugars)

•Cellular respiration moves electrons from fuel to other molecules... Continue reading "Mitochondria, Respiration, and Photosynthesis: Energy Processes in Cells" »

ACID OR BASES: Substances that react with each other according to the following reaction