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Chemistry Formulas for Nuclear Chemistry (Radioactivity)

Chemistry Formulas for Nuclear Chemistry (Radioactivity)

Empirical relationship between size of nucleus and its mass number is
            R = R0A1/3
            R = radius of nucleus,
            A = mass number,
            R0 = contestant = 1.4x10-13cm

Rate of Decayof radioactive substance

            K = decay constant,
            N = No. of atoms,
            t = time of decay,
            dN = small fraction of N,
            dt = small fraction of t

Value of Decay Constant

            N0 = No. of atoms originally present,
            N = No. of atoms present after time t

Half Life Time (t1/2)

            t1/2 = 0.693/K
            K = decay constant

Average Life Time (T)

            Average life time (T) =Sum of the lives of the nuclei/ Total number of nuclei
            T = 1/K 
            Average life time (T) = 1.44 x Half-life (T1/2)
            K = decay constant
            T = Average Life Time
            T1/2 = Half Life

Specific Activity

            Specific Activity = Rate of decay/m
                                      = KN/m
                                      = K x Avogadro Number/ Atomic Mass in gram
            N = Number of Radioactive nuclei that undergoes disintegration

Units of Radioactivity

            Standard unit of radioactivity is curie (c).
            1c = Activity of 1gram Ra226 = 3.7 x 1010dps
            dps = disintegrations per second
millicurie (mc) = 3.7 x 107dps
microcurie (µc) = 3.7 x 104dps
Other units of radioactivity are Rutherford (rd) and Becquerel (Bq).

Rutherford (rd)

1rd = 106dps

Becquerel (Bq)

            Becquerel (Bq) is the SI unit of radioactivity.
                        1Bq = 1 disintegrations per second
                        1 Bq = 1 dps

Radioactive Equilibrium

            A ----à B ----à C
            At steady state,
                        NA/NB = KB/KA = TA/TB
            KA = radioactivity constant for the process A---àB
            KB = radioactivity constant for the process B---àC
            TA = average life period of A
            TB = average life period of B
Radioactive Equilibrium in terms of half-life periods,
            NA/NB = (T1/2)A/ (T1/2)B

Chemistry Formulas for Structure of Atom Part 1

Chemistry Formulas of Structure of Atom

Chemistry Formulas from Rutherford Atomic Model

·         Radius of Nucleus, rn = r0 × A1/3
Where, A = Mass Number,
               r0 = Proportionality Constant = 1.4 × 10-13 cm
·         Volume of the nucleus = Approx. 10-39 cm3
·         Volume of the atom = Approx. 10-24 cm3
·         Density of the nucleus = 1014 g cm-3

Important Characteristics of Three Fundamental Particles
1.      Electron
·         Charge on an Electron = -1.602×10-19 coulombs.
·         Mass of an Electron = 9.11×10-28 g
·         Specific Charge (e/m ratio) of electrons (cathode rays) = 1.76×108 coulombs/gram
·         Radius of the electron = 10-15 cm
·         Density of the electron = 2.17×1017g/cc
·         Mass of one mole of the electrons = Approx. 0.55mg
·         Charge on one mole of the electrons = 96500 Coulombs = 1 Faraday
2.      Proton
·         Mass of Proton = 1.672×10-24g
·         Charge on Proton = 1.602×10-19 Coulombs
·         Specific Charge of Proton = 9.58×104 Coulombs/gram
·         Mass of one mole of proton = 1.007 gram
·         Charge on one mole of proton = 96500 Coulombs = 1 Faraday
·         Volume of Proton = Approx. 1.5×10-38cm3
3.      Neutron
·         Mass of Neutron = 1.675×10-24g
·         Specific Charge on Neutron = 0
·         Density of Neutron = 1.5×1014g/cc
·         Mass of one mole of neutron = 1.008g
4.      Other Sub-Atomic Particles of Atom
·         Positrons
·         Neutrions
·         Mesons
Chemistry Formulas of Atomic Number (Z) and Mass Number (A)
·         General Symbol for an Atom of Element (E) indicating its Atomic Number (Z) and Mass Number (A)
·         Atomic Number (Z) = Number of Protons = Number of Electrons
·         Mass Number (A) = Number of Protons + Number of Neutrons
·         No. of Neutrons = A – Z

Famous Scientists and their Inventions

Scientists and Their Important Research in the Field of Chemistry

chemist, chemistry, chemistry experiments, chemistry scientists, famous chemists, famous scientists, great scientists, list of scientists, names of scientists, scientific name, scientist names,
Given below is the list of scientists and their important research and inventions. These famous scientists or chemists perform many science and chemistry experiments which help in the development of Chemistry and Science. 

 List of Famous Scientists and their Inventions

List of Scientists
Research and Inventions
Ernest Rutherford
Bombardment of Atoms by alpha-particles
J. J. Thompson
Discovery of Electron, e/m of Electron
Eugen Goldstein
Discovery of Proton
James Chadwick
Discovery of Neutron
Louis De-Broglie
Wave Equation
Niels Henrik David Bohr
Atomic Model, Long Form of Periodic Table
Albert Einstein
Photoelectric Effect
Niels Bohr, Wolfgang Pauli and Friedrich Hund
Distribution of electrons
Heisenberg Principle
Uncertainty Principle
Marie Curie
Francis William Aston
Mass Spectrograph
Dmitri Ivanovich Mendeleev
Periodic Law, Periodic Table
Sidwick and Powell
Theory of Hybridisation
Louis Allred and Eugene George Rochow
Robert Sanderson Mulliken
Robert Boyle
Boyle’s Law, Relation Between P and V
Jacques Alexandre César Charles
Charle’s Law, Relation Between T and V
Lorenzo Romano Amedeo Carlo Avogadro
Avogadro’s Law, Relation Between V and number of molecules (n)
John Dalton
Dalton’s Law, Relation Between the Total Pressure and Partial Pressure of Individual Gases
Thomas Graham
Graham’s Law, Relation Between the Rate of Diffusion and Density (or Molecular Weight) of Gases
François Marie Raoult
Raoult’s Law, Relation Between Partial Vapour Pressure and Mole Fraction
Harold Clayton Urey
Heavy Water
Henry Louis Le Chatelier
Le Chatelier Principle, Effect of P, T and Concentration of Reactants on the System in Equilibrium

10 Facts About Earth

Top 10 Interesting Facts About Mother Earth

10 facts about planet earth
Lets learn 10 interesting facts about mother earth...
1. Earth is the 3rd planet from the Sun.
2. About 2/3 of the mother earth is covered by water.
3. Age of planet earth is about 4.5 billion years.
4. Earth has a moon, which orbiting earth and completes one cycle in a month.
5. Earth is home to millions of species including humans and support life.

6. Earth has an atmosphere containing about 21% oxygen.
7. Earth is the only planet in the solar system that has life.
8. Earth orbit around sun, and completes one cycle in 365¼ days.
9. Earth is at 150 million kilometers from the sun.
10. Earth is NOT an exact sphere, the diameter around the equator is slightly larger than the diameter around the north and south poles.

Analytical Balance

Analytical Balance

What is an analytical balance?

what is Analytical Balance
Analytical balance is a lab-instrument used to determine mass of any matter very precisely. These analytical balances are very sensitive and expensive lab-instruments, and also upon the accuracy and precision of analytical balance the accuracy of lab-analysis result depends so handle these balances very carefully. Generally used analytical balances are balances with the capacity of 100 gram to 200 gram and the sensitivity of 0.1 milligram to 0.001 milligram. For any quantitative chemical analysis there is need of analytical balance for the weighing of sample for analysis and weighing of reagents for solution preparation. Analytical balance pan used to put sample on it is enclosed in a glass-fitted case, means analytical balance sensitivity requires that it to be protected by the draft shield or enclosure.
analytical balances

Definition of Analytical Balance

Analytical balance is a lab instrument with a scale to measure the mass to a high degree of precision. Generally used analytical balances are balances with the capacity of 100 gram to 200 gram and the sensitivity of 0.1 milligram to 0.001 milligram.

Where are analytical balances used?

Analytical balances are used in labs so also known as ‘Lab Balances’. In labs analytical balances are used for quantitative analysis like for measuring of sample, preparation of standard solutions etc.

How to weigh on an analytical balance?

These are the following steps to start weighing operation on an analytical balance-
  • Wear hand gloves.
  • Open the door of balance and place the container on pan of analytical balance.
  • Now, close the door of the analytical balance and wait for some time.
  • After some time value on balance display or scale get stabilizes, and shows some weight.
  • Now, press the tare button to get 0.0000 gram reading on display.
  • Add the sample until the required weight.
  • Now, close the door and wait for some time.
  • After some time value on balance display or scale get stabilizes, and shows some weight.
  • Record the net weight.
  • Clean the balance after use.

What is analytical balance uncertainty?

Analytical balance uncertainty is the margin of error in weighing, means when making measurements or weighing there is always an element of uncertainty in measurements or weighing. Determination of measurement uncertainty in analytical balance results is an integral part of the balance calibration.

Why should I calibrate my analytical balance?

Calibration of analytical balance is very necessary because balance calibration ensures that weighing balance is precise, correct, truthful, accurate, and satisfies different standards like ISO, GLP, and GMP. Calibration of analytical balances should be documented, as it specifies the quality of measurements. Documented calibration should be performed repeatedly, at some time intervals (like 3months+/-15days). 

How should I calibrate my analytical balance?

You should not calibrate your balance on your own, but it should be calibrated by third party. Means, calibration of balance is performed by third party authorized service technician.  This third party authorized service technician follow a standard procedure, and utilizes some calibration software to calibrate your analytical balance.

What is the analytical balance minimum weight?

Generally minimum weight of analytical balance is not fixed, means it is different for different balances and it depends on different factors like performance of load cell, location of balance, and surrounding environment. Minimum weight is smallest weight that can be measured with accuracy. If we try to measure below this minimum weight, we get results higher relative measurement uncertainty than the required weighing accuracy. So measurements below minimum weight cannot be trusted.
If you want to determine the minimum weight of your balance, you need to assess measurement uncertainty in the working environment.

Analytical balance accuracy and precision – what is the difference and how to test them?

Precision in balances refers to the closeness of two or more measurements to each other, means if we measure 5gram sample and its display shows 5.0001 in 1st time measurement, 5.0000 in 2nd time measurement, 4.9999 in 3rd measurement, and 5.0000 in 4th measurements so all these results (5.0001, 5.0000, 4.9999, and 5.0000) are very close to each other.
Accuracy in balances means how accurate result it gives so, Accuracy in balances refers to the closeness of a measured value to a known value, and Accuracy in balances is based on repeatability, readability, eccentricity and non-linearity. Accuracy of analytical balance can be tested using
  • A traceable calibrated weight also known as external reference weight having a known mass. And these weights are calibrated by third party and come with documented proof.
  • Accuracy of balance must be determined at its location of use.

Do you know ?

What is Analytical Chemistry ?

Analytical chemistry is all about, what an analytical chemist do in an analytical chemistry lab. And simply we can say that analytical chemistry is the branch of chemistry for qualitative analysis and quantitative analysis of compounds and mixtures by using different test methods and techniques like flame tests, chemical tests, precipitation, titration, chromatography, spectroscopy, separation, microscopy etc.
Definition of Analytical Chemistry- Analytical Chemistry is the branch of chemistry deals with the study of material examination to separate out them into different components and identifying all components and how much these components present in material. There are different analytical methods and techniques to perform these tasks... read more
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