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  2. Number - Wikipedia

    en.wikipedia.org/wiki/Number

    A real number can be expressed by a finite number of decimal digits only if it is rational and its fractional part has a denominator whose prime factors are 2 or 5 or both, because these are the prime factors of 10, the base of the decimal system. Thus, for example, one half is 0.5, one fifth is 0.2, one-tenth is 0.1, and one fiftieth is 0.02.

  3. Petroleum - Wikipedia

    en.wikipedia.org/wiki/Petroleum

    Petroleum also makes up 40 percent of total energy consumption in the United States, but is responsible for only one percent of electricity generation. [53] Petroleum's worth as a portable, dense energy source powering the vast majority of vehicles and as the base of many industrial chemicals makes it one of the world's most important commodities .

  4. Water (data page) - Wikipedia

    en.wikipedia.org/wiki/Water_(data_page)

    of fusion at 273.15 K, Δ fus H: 6.01 kJ/mol Entropy change of fusion at 273.15 K, 1 bar, Δ fus S: 22.0 J/(mol·K) Std enthalpy change of vaporization, Δ vap H o: 44.0 kJ/mol Enthalpy change of vaporization at 373.15 K, Δ vap H: 40.68 kJ/mol Std entropy change of vaporization, Δ vap S o: 118.89 J/(mol·K) Entropy change of vaporization at ...

  5. Pi - Wikipedia

    en.wikipedia.org/wiki/Pi

    The number π (/ p aɪ / ⓘ; spelled out as "pi") is a mathematical constant, approximately equal to 3.14159, that is the ratio of a circle's circumference to its diameter.It appears in many formulae across mathematics and physics, and some of these formulae are commonly used for defining π, to avoid relying on the definition of the length of a curve.

  6. e (mathematical constant) - Wikipedia

    en.wikipedia.org/wiki/E_(mathematical_constant)

    The number e is a mathematical constant approximately equal to 2.71828 that is the base of the natural logarithm and exponential function.It is sometimes called Euler's number, after the Swiss mathematician Leonhard Euler, though this can invite confusion with Euler numbers, or with Euler's constant, a different constant typically denoted .

  7. History of mathematics - Wikipedia

    en.wikipedia.org/wiki/History_of_mathematics

    Babylonian mathematics were written using a sexagesimal (base-60) numeral system. [21] From this derives the modern-day usage of 60 seconds in a minute, 60 minutes in an hour, and 360 (60 × 6) degrees in a circle, as well as the use of seconds and minutes of arc to denote fractions of a degree.

  8. Chemical industry - Wikipedia

    en.wikipedia.org/wiki/Chemical_industry

    15 PTT Global Chemical: $16.2 Bangkok, Thailand 16 Toray Industries: $15.5 Tokyo, Japan 17 Evonik Industries: $15.0 Essen, Germany 18 PPG Industries: $14.2 Pittsburgh, Pennsylvania, United States 19 Braskem: $14.2 São Paulo, Brazil 20 Yara International: $13.9 Oslo, Norway 21 Covestro: $13.4 Leverkusen, Germany 22 Sumitomo Chemical: $13.3 ...

  9. Specific modulus - Wikipedia

    en.wikipedia.org/wiki/Specific_modulus

    Specific modulus is a materials property consisting of the elastic modulus per mass density of a material. It is also known as the stiffness to weight ratio or specific stiffness.