Chemistry

Antoine Lavoisier discovered the role of oxygen in combustion, established the Law of Conservation of Mass, and wrote the first modern list of elements. [Memory Trick: He set the 'Laws' of chemistry, acting as a shiny 'Lavoisier' (advisor) of science.]

Heavy water contains the hydrogen isotope deuterium (which has a neutron in its nucleus). It slows down neutrons in nuclear reactors. [Memory Trick: 'D' stands for 'Double' heavy hydrogen isotope = D2O.]

Diamond possesses extreme hardness because of strong covalent bonds in its giant 3D crystal lattice. [Memory Trick: Carbon under immense pressure shines as a brilliant, unbreakable 'Diamond'.]

The gastric juices of the stomach contain hydrochloric acid (~0.5%), yielding a highly acidic pH level of 1.5 to 3.5. [Memory Trick: 'H'ighly 'C'orrosive 'L'iquid inside our belly = HCl.]

The pH scale goes from 0 (extremely acidic) through 7 (neutral water) up to 14 (extremely alkaline/basic). [Memory Trick: It ends at '14' (double of lucky number 7) which represents maximum alkaline strength.]

Carbon dioxide is denser than oxygen and acts as a heavy blanket over the fire, choking off the oxygen fueling the combustion. [Memory Trick: CO2 acts as a heavy 'C'hemically 'O'xygen '2' blocker.]

Nitrogen covers about 78% of dry atmosphere, while oxygen is second at ~21%, and argon third at ~0.93%. [Memory Trick: 'N'itrogen occupies the 'N'inety percent vicinity (almost 80%) of the atmosphere.]

Iron rust is a slow electrochemical oxidation process where iron reacts with water and oxygen to yield hydrated iron(III) oxide. [Memory Trick: Rust requires 'hydration' (water) + 'oxygen' (ferric oxidation) = Hydrated Ferric Oxide.]

Solder is traditionally a fusible alloy made of lead (Pb) and tin (Sn), possessing a low melting temperature. [Memory Trick: 'S'older joints are formed easily when a hot 'P'en ('P'b) melts a 'S'hinny 'n'ail ('S'n).]

Sulfur dioxide and nitrogen oxides react with water vapor in the atmosphere to formulate sulfuric and nitric acids, falling as acid rain. [Memory Trick: Industrial 'S'moke ('S'O2) and vehicle 'N'oise ('N'Ox) dissolve to melt structures with acid rain.]

Galvanizing covers iron or steel with a thin zinc layer, which acts as a sacrificial anode, corroding in place of the underlying metal. [Memory Trick: Galvan'z'ation wraps a shield of 'z'inc around the iron joint.]

Noble gases have a full outer shell of 8 valence electrons (stable octet, or duet for Helium), requiring zero donation/acceptance of electrons. [Memory Trick: Nobles are rich and 'completely satisfied' (full octet), so they don't interact with others.]

Plaster of Paris is calcium sulfate hemihydrate. When mixed with water, it rehydrates to form gypsum, setting into a hard solid. [Memory Trick: Plaster has only 'half' ('Hemi') a splash of water, while Gypsum has 'double' ('Di').]

Baking soda is sodium hydrogen carbonate (sodium bicarbonate). Under heat, it releases CO2 gas bubbles, expanding baked dough. [Memory Trick: When we cook at home, we buy ('Bi'-carbonate) baking soda to bake fluffy buns.]

Washing soda is sodium carbonate decahydrate, which cleans fabric by softening water and binding magnesium/calcium ions. [Memory Trick: No need to 'Bi' anything, just pure 'Sodium Carbonate' to wash clothes.]

Bleaching powder is calcium hypochlorite (calcium oxychloride). It releases active chlorine to sterilize organic stains and bacteria. [Memory Trick: 'Ca'lcium 'O'xy 'Cl2' (Chloride) = CaOCl2 which smells like chlorine pools.]

Liquefied Petroleum Gas (LPG) consists mainly of propane and butane gases under pressure, mixed with ethyl mercaptan for leak detection smells. [Memory Trick: Our kitchen 'PG' cylinders contain 'P'ropane and 'B'utane.]

Biogas is formed by anaerobic breakdown of organic waste, yielding roughly 50-75% methane (CH4) gas. [Memory Trick: Swamps and cows produce lots of 'Methane' (CH4) gas.]

Vinegar is basically a dilute solution of acetic acid (CH3COOH) generated through ethanol fermentation by acetic acid bacteria. [Memory Trick: 'A'cetate ('A'cetic) sounds like 'A'cidic vinegar salad dressing.]

Pencil lead contains no poisonous lead. It consists of a mixture of solid clay and soft graphite (a layered carbon allotrope that easily rubs off onto paper). [Memory Trick: Draw a 'graph' with 'Graphite' pencil leads.]

Mercury (Hg or quicksilver) has a very low freezing point (-39 °C), keeping it liquid at room temperature. It is widely used in traditional thermometers. [Memory Trick: 'Mercury' is the hot fluid planet inside clinical thermometer tubes.]

Bromine is the only nonmetallic chemical element that is a liquid at room temperature. It has a choking, pungent odor. [Memory Trick: 'Bro'mine is the red liquid 'Bro' of shiny gray metal Mercury.]

Wrought iron is highly pure iron containing slag fibers, making it malleable, rust-resistant, and easily welded. [Memory Trick: Iron that has been 'wrought' (worked/beaten) is cleaned of carbon residues, leaving it extremely pure.]

In 1828, Friedrich Wöhler successfully synthesized urea, proving carbon organic compounds could be produced synthetically from inorganic ammonium cyanate. [Memory Trick: 'Urea' is found in urine, proving human waste molecules could be made in a lab!]

Chlorofluorocarbons release chlorine atoms under UV light in the stratosphere, destructively cataloging ozone molecules. [Memory Trick: 'C'hlorine 'F'reezer 'C'hemicals = CFCs.]