The Mole and Avogadro’s Number

2021 ◽  
pp. 13-18
Author(s):  
Christopher O. Oriakhi
Keyword(s):  
Amount Of Substance ◽  
Avogadro’S Number

Measuring Chemical Quantities: The Mole introduces the mole as the chemist’s unit for the amount of substance and discusses its relationship with Avogadro’s number of chemical entities including atoms, ions, molecules and formula units. Calculations demonstrate the use of the mole to convert between mass and the number of chemical entities.

A Complementary Relation of Fluctuations between Energy and Temperature in a Small Specimen

2020 ◽  
pp. 2150026
Author(s):  
Shoichi Nagata
Keyword(s):  
Simple Formula ◽  
Heat Bath ◽  
Temperature Fluctuations ◽  
Physical Models ◽  
Small Specimen ◽  
Amount Of Substance ◽  
Complementary Relation ◽  
Avogadro’S Number ◽  
Number Formula ◽  
Quantitative Analyses

Research on fluctuations in energy and temperature is presented for a small specimen. The small specimen in contact with a heat bath shows energy fluctuations, [Formula: see text], at the constant temperature. On the other hand, when this small specimen is isolated from the reservoir and adiabatic isolation is kept, it exhibits temperature fluctuations, [Formula: see text], at the constant energy. This means that the temperature is unsharp if a sharp energy is assigned. A complementary relation between [Formula: see text] and [Formula: see text] is proposed in a simple formula. The connection between [Formula: see text] and [Formula: see text] is mediated by the heat capacity [Formula: see text]. This complementary relation is valid in general and it does not depend on the amount of substance. If the constituent number[Formula: see text] of the system is of the order of Avogadro’s number, then the fluctuations have been masked by large [Formula: see text]and we cannot see the influence of the fluctuations. However, when the number [Formula: see text] decreases, the intrinsic features of fluctuations come out gradually. This paper presents the quantitative analyses of the fluctuations in the energy and temperature for several physical models. Typical characteristics in the fluctuations can be clearly seen only in a small specimen, which are shown in the graphical representations. It is stressed that the values of [Formula: see text] and [Formula: see text] are defined for the different prescribed conditions specified above.

A relationship between the Avogadro’s number NA and the transition frequency of the caesium 133 atom ΔνCs

2021 ◽  
Vol 34 (1) ◽  
pp. 12-16
Author(s):  
Teodor Ognean
Keyword(s):  
Ground State ◽  
International System ◽  
Transition Frequency ◽  
Amount Of Substance ◽  
Weights And Measures ◽  
Avogadro’S Number ◽  
System Of Units ◽  
Measurement Units ◽  
Definition Of ◽  
New Si

At the 26th meeting of the General Conference on Weights and Measures (CGPM) held on 13‐16 November 2018 at Versailles, France, the new International System of Units (SI) was established. Following the CGPM’s decision, the new SI units were established based upon a set of seven defining constants. This set of constants is the most fundamental feature in the definition of the entire system of units. What is truly remarkable about the new SI is the fact that all measurement units, except the amount of substance mole and Avogadro’s number NA , are defined based on the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom <mml:math display="inline"> <mml:msub> <mml:mrow> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:mi>ν</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">Cs</mml:mi> </mml:mrow> </mml:msub> </mml:math> equal to 9 192 631 770 Hz. This article, based on dimensional analysis, presents the possibility of connecting the Avogadro’s number NA and the mole, to the transition frequency <mml:math display="inline"> <mml:msub> <mml:mrow> <mml:mo>Δν</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext>Cs</mml:mtext> </mml:mrow> </mml:msub> </mml:math> .

In Vivo Wound Healing Activity of Spirulina platensis

2019 ◽  
Vol 18 (1) ◽  
pp. 06-16
Author(s):  
R. Seghiri ◽  
A. Essamri
Keyword(s):  
Wound Healing ◽  
Spirulina Platensis ◽  
Therapeutic Agent ◽  
Conventional Medicine ◽  
Folk Medicine ◽  
Chemical Burns ◽  
Amount Of Substance ◽  
Test Population ◽  
Wound Healing Activity

Spirulina is a microalga used in traditional folk medicine in Morocco for the treatment of various health disorders. The wound healing activity of Moroccan Spirulina is unknown. In the current study, aqueous extracts of Spirulina platensis were investigated for acute toxicity and wound healing activity in Swiss Albino mice and White New Zealand rabbits, respectively. The LD50 (amount of substance required to kill 50% of the test population) of the microalga was greater than 5,000 mg/kg. Healing after application of the same amount of ointment on differently induced (mechanical, chemical, and thermal) wounds was about the same, over five weeks. Aqueous extract had remarkable healing activity on rabbits’ skin, possessing significantly greater healing effect for mechanical and chemical burns than controls. Moreover, the hair growing time was faster in treated groups; Spirulina-treated groups did not show any contamination with microbes compared to others. This study affirms that Spirulina platensis can be considered as a potential therapeutic agent for wound healing not only as a complementary medicine but also in conventional medicine.

Amount of substance: an alternative proposal

1978 ◽  
Vol 13 (5) ◽  
pp. 269-272 ◽  
Author(s):  
Richard G Forbes
Keyword(s):  
Amount Of Substance ◽  
Alternative Proposal

scholarly journals The viscosity of strong electrolytes measured by a differential method

1934 ◽  
Vol 145 (855) ◽  
pp. 475-488 ◽  
Keyword(s):  
Dielectric Constant ◽  
Empirical Equation ◽  
Relative Viscosity ◽  
Absolute Temperature ◽  
Differential Method ◽  
Theoretical Equation ◽  
Electronic Charge ◽  
Accurate Data ◽  
Avogadro’S Number ◽  
Strong Electrolytes

Until quite recently no satisfactory equation had been obtained for the representation of the viscosity of dilute solutions of strong electrolytes. An empirical equation was recently proposed by Jones and Dole to fit the only accurate data then available. Their equation may be represented thus : η = 1 + A √ c + B c , η = relative viscosity of the solution c = concentration in moles per litre A and B are constants. Jones and Dole realized that the coefficient A is due to interionic forces and in a series of later publications Falkenhagen, Dole and Vernon have deduced a theoretical equation giving values of A in terms of well-known physical constants. Their complete equation may be written η = 1 + ε √N v 1 z 1 /30η 0 √1000D k T ( z 1 + z 2 ) 4 π × [¼ μ 1 z 2 + μ 2 z 1 / μ 1 μ 2 - z 1 z 2 (μ 1 - μ 2 ) 2 /μ 1 μ 2 (√μ 1 z 1 + μ 2 z 2 + √(μ 1 + μ 2 ) ( z 1 + z 2 ) ) 2 ]√ c , where N = Avogadro's number v 1 , v 2 = numbers of ions z 1 , z 2 = valencies of ions μ 1 , μ 2 = absolute mobilities of ions D = dielectric constant of solvent k = Boltzmann's constant ε = electronic charge η 0 = viscosity of solvent T = absolute temperature.

scholarly journals Channel noise in nerve membranes and lipid bilayers

1975 ◽  
Vol 8 (4) ◽  
pp. 451-506 ◽  
Author(s):  
F Conti ◽  
E. Wanke
Keyword(s):  
Brownian Motion ◽  
Lipid Bilayers ◽  
Fluctuation Phenomena ◽  
Channel Noise ◽  
Fluctuation Analysis ◽  
Electronic Charge ◽  
Basic Principles ◽  
Avogadro’S Number ◽  
Insight Into

The basic principles underlying fluctuation phenomena in thermodynamics have long been understood (for reviews see Kubo, 1957; Kubo, Matsuo & Kazuhiro 1973 Lax, 1960). Classical examples of how fluctuation analysis can provide an insight into the corpuscular nature of matter are the determination of Avogadro's number according to Einstein's theory of Brownian motion (see, e.g. Uhlenbeck & Ornstein, 1930; Kac, 1947) and the evaluation of the electronic charge from the shot noise in vacuum tubes (see Van der Ziel, 1970).

Highly sensitive refractive index sensor for detection of Hg2+ based on Fano-like resonance in metal-dielectric-metal meta-structure

2021 ◽  
Author(s):  
Shuangxiu Yuan ◽  
Xuebo Sun ◽  
Jing Li ◽  
Yan Li ◽  
Fufang Su ◽  
...  
Keyword(s):  
Refractive Index ◽  
Limit Of Detection ◽  
Wavelength Shift ◽  
Refractive Index Sensor ◽  
Large Area ◽  
Amount Of Substance ◽  
Resonance Modes ◽  
Dipole Resonance ◽  
Highly Sensitive ◽  
Fabry Perot

Abstract We experimentally and theoretically investigate Fano-like resonance in large-area Au/SiO2/Au nano-patches meta-structure, which is originating from the coupling between Fabry Perot resonance and magnetic dipole resonance modes. A highly sensitive refractive index sensor based on the lineshape analysis is obtained. The extracted wavelength shift with the amount of substance of Hg2+ changing from 10-3 pmol to 1 nmol has a linear dependence, and the sensitivity can reach to ultra-low limit of detection (LOD) as 10-3 pmol. This study may provide an approach for the development and modification in sensing.

scholarly journals The estimation of electric moment in solution by the temperature coefficient method. Part I.—Experimental method and the electric moments of some benzyl compounds

1933 ◽  
Vol 142 (846) ◽  
pp. 173-197 ◽  
Keyword(s):  
Single Molecule ◽  
Polar Solvent ◽  
Fundamental Equation ◽  
Absolute Temperature ◽  
Electric Moment ◽  
Avogadro’S Number ◽  
Boltzmann Gas ◽  
Different Temperatures ◽  
The Moment ◽  
Coefficient Method

The theory of the estimation of the electric moment of molecules dissolved in a non-polar solvent is now well known. The fundamental equation is P 2∞ = 4 π /3 N (α 0 + μ 2 /3 k T) (1) in which the symbols have the following significance: P 2∞ the total polarizability of the solute per grain molecule at infinite dilution, N Avogadro’s number, α 0 the moment induced in a single molecule by unit electric field, k the Boltzmann gas constant, T the absolute temperature, and μ the permanent electric moment of the molecule. This equation is of the form P 2∞ = A + B/T, (2) where A = 4 π /3 Nα 0 and B = 4 π /9 . N μ 2 / k , from which it follows that if A and B are constant, i. e ., independent of temperature, then each may be evaluated from a series of measurements of P 2∞ at different temperatures or alternatively B (and hence μ ) may be obtained from one value of P 2∞ at one temperature, provided that A can be obtained by some independent method.

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