Notes, abstracts, papers, exams and problems of Chemistry

Ionic Bonding

Bonding between a non-metal and a metal where electrons are transferred from the metal to the non-metal. This results in the non-metal forming a negative ion and the metal forming a positive ion. The structure is a giant ionic lattice with strong electrostatic forces between ions. A lot of energy is needed to break these forces, resulting in high melting and boiling points. Ionic compounds conduct electricity when aqueous or molten, as the ions are free to move around. They can be represented using dot and cross diagrams.

Covalent Bonding

Bonding between two non-metals. Covalent compounds do not conduct electricity as there are no charged particles. Small molecules are liquids or gases at room temperature due to weak intermolecular... Continue reading "Chemical Bonding and Structure" »

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" »

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

ADDITION

• and
• Also
• Besides
• In addition to
• Additonally
• likewise
• Moreover
• Furthermore
• Not only… but also
• Not only… but… as well
• both… and…

CONDITION

• if
• even if
• only if
• whether … or not
• unless
• provided (that)
• providing
• as long as
• in case
• in case of
• in the event of
• once

ALTERNATIVE

• or
• either… or…
• neither… nor...
• else
• otherwise

REASON

• As
• Because
• As a result of…
• As a consequence of...
• For
• For this reason
• since
• due to...
• owing to

COMPARATIVE

• as
• as… as…
• not as… as…
• not so… as…
• as if
• as though
• likewise
• similarly
• ...than

CONTRAST

• But
• however
• nonetheless
• Nevertheless
• yet
• still
• ...instead
• instead of
• despite
• On the contrary
• On the one hand...
• on the other hand
• In contrast
• although... even though
• though
• whereas
• while

EXPLANATION

• i.e.
• that is
• that is to say

EXAMPLE

• e.g.
• for example
• for instance
• like
• such

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

•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" »