General Science - 3

Lime water is a saturated solution of calcium hydroxide, Ca(OH)2. It is commonly used in chemistry to test for the presence of carbon dioxide.

Transmutation is the conversion of one chemical element or isotope into another. This occurs through nuclear reactions, such as radioactive decay or bombardment.

Crude oil is a mixture of hydrocarbons with different boiling points. Fractional distillation separates these components based on their different boiling points.

Electric bulbs are filled with an inert gas, typically nitrogen or argon, to prevent the tungsten filament from oxidizing and burning out.

Nitrogen makes up about 78 percent of the atmosphere. Its presence dilutes oxygen, which is highly reactive, preventing fires from spreading too quickly and protecting biological tissues from oxygen toxicity.

Marsh gas is primarily composed of methane, which is produced by the anaerobic decomposition of organic matter in wetlands and coal mines.

Galvanization is the process of applying a protective zinc coating to steel or iron to prevent rusting. The zinc acts as a sacrificial anode.

Nitrogen fixation is the chemical process by which atmospheric nitrogen is converted into ammonia or related nitrogenous compounds in soil or aquatic systems.

Graphite is an allotrope of carbon, meaning it is composed entirely of carbon atoms. Sugar, acetic acid, and methane all contain hydrogen and oxygen in addition to carbon.

PVC (polyvinyl chloride) is a polymer made by the polymerization of vinyl chloride monomers.

A pH of 12 indicates a strongly basic solution. Sodium hydroxide (NaOH) is a strong base, while the others are either neutral or acidic.

A pH less than 7 indicates an acidic solution. Vinegar contains acetic acid, which makes the solution acidic.

Silicon is the second most abundant element in the Earth's crust, primarily found in the form of silica (silicon dioxide) in sand and rocks.

The atomic number is defined as the number of protons in the nucleus of an atom, which uniquely identifies the element.

The reaction between a fat or oil (like linseed oil) and a strong base (like caustic soda/sodium hydroxide) is called saponification, which produces soap.

Azo dyes are characterized by the presence of the azo group, which consists of two nitrogen atoms double-bonded to each other (-N=N-).

Nylon, cellulose, and starch are all polymers (long chains of repeating units). Glucose is a simple sugar (monosaccharide) and is not a polymer.

Chloromycetin (chloramphenicol) is a well-known antibiotic used to treat various bacterial infections.

Cinnabar is the bright red form of mercury(II) sulfide and is the main ore of mercury.

Exothermic reactions release energy in the form of heat to the surroundings.

Tetraethyl lead was historically added to gasoline to improve its octane rating and prevent engine knocking.

Oxygen is the most abundant element in the human body by mass, primarily because the body is composed largely of water (H2O).

Barbituric acid derivatives, known as barbiturates, are central nervous system depressants used as sedatives or hypnotics.

Turpentine is a fluid obtained by the distillation of resin harvested from living trees, mainly pines.