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Saponification is the hydrolysis of an ester (like fats and oils) using a strong alkali (like sodium hydroxide) to produce soap (a metallic salt of a fatty acid) and glycerol

The basicity of an acid is the number of replaceable hydrogen ions per molecule of the acid. Since one molecule of tetraoxosulphate(VI) acid ($H_2SO_4$ ) can furnish two hydrogen ions, its basicity is 2

The molar mass of FeS is $56 + 32 = 88 g/mol$ . The mass of sulfur in 35.2 g of FeS is calculated as: Mass of $S = (\frac{32}{88}) \times 35.2 g = 12.8 g$ .

Halogens are the elements in Group 17 of the periodic table, including fluorine, chlorine, bromine, iodine, and astatine. Chlorine is a representative example

Crude oil is separated into fractions through fractional distillation. However, to produce higher-quality gasoline with a better octane rating, processes like cracking (breaking down large hydrocarbon molecules) and reforming (rearranging molecules) are used to produce more branched and aromatic hydrocarbons

Hard water contains dissolved calcium and magnesium salts. These ions react with soap to form an insoluble precipitate called scum, which prevents the soap from lathering and can stain clothes and fixtures. This leads to a waste of soap.

The modern standard for relative atomic mass is based on the carbon-12 isotope, which is assigned a mass of exactly 12 atomic mass units. The relative atomic mass of an element is the average mass of its atoms compared to one-twelfth the mass of a carbon-12 atom

Chromatography, such as paper or column chromatography, separates components of a mixture based on their differing affinities for a stationary phase and a mobile phase

A supersaturated solution contains more dissolved solute than a saturated solution at that temperature. It is a metastable state, and the excess solute will often crystallize out if disturbed

Thomson proposed the plum pudding model of the atom in which electrons were embedded in a sphere of uniform positive charge

Rust is a hydrated form of iron(III) oxide, with the chemical formula $Fe_2O_3 \cdot nH_2O$ . Corrosion, including rusting, is an electrochemical process where iron reacts with oxygen and water

Carbohydrates are classified into monosaccharides, disaccharides, and polysaccharides. Glucose is a simple sugar, a monosaccharide, which is the basic unit of more complex carbohydrates like starch and cellulose

Air is a mixture because its components, like nitrogen, oxygen, and argon, are not chemically bonded to each other. They can be separated physically, for example, by fractional distillation of liquid air

Air is a mixture because its constituent gases, such as nitrogen, oxygen, argon, etc., are not chemically combined and can be separated by physical methods like fractional distillation of liquefied air. The composition of air also varies slightly depending on the location and conditions, which is characteristic of a mixture, not a compound

The atomic number (Z) equals the number of protons and, in a neutral atom, the number of electrons. The mass number (A) is the sum of protons and neutrons. For this element, protons = 17, electrons = 17. $Neutrons = Mass Number - Atomic Number = 35 - 17 = 18$

Galvanization is a form of cathodic protection where a layer of a more reactive metal, usually zinc, is applied to a steel or iron surface. The zinc corrodes preferentially, protecting the iron underneath from rusting

The compound $HOOC-COOH$ has two carbon atoms and two carboxyl functional groups. The IUPAC naming for dicarboxylic acids is based on the parent alkane name with the suffix "-dioic acid." For a two-carbon chain, the parent alkane is ethane, so the name is ethanedioic acid, commonly known as oxalic acid

Brass is an alloy primarily composed of copper and zinc. Bronze is an alloy of copper and tin. Steel is an alloy of iron and carbon

Aluminium is a very reactive metal and cannot be extracted by reduction with carbon. It is extracted commercially by the electrolysis of its purified ore, bauxite, which is dissolved in molten cryolite

A chemical change, also known as a chemical reaction, involves the rearrangement of atoms and molecules to form new substances with different chemical compositions and properties. This process requires the breaking and forming of chemical bonds