Chemical Arithmetic and Chemical Stoichiometry

Chemical Arithmetic

Chemistry is mainly an experimental science, in which we study about physical properties and chemical properties of different substances and measure these properties up to highest possibility with great efforts to get results with great precision and accuracy. Results of our experimental measurements or numerical problems have-

• Arithmetic number,

• Unit of measurement.

Chemical Stoichiometry

Chemical stoichiometry is all about the calculation or measurement of relative quantities of the reactants and products involved in any chemical reaction. Stoichiometry utilizes the Law of Conservation of Mass or Principle of Mass Conservation so according to law of conservation of mass, "Matter is neither created nor destroyed". Which means in a chemical reaction, amount of elements remains same in starting when only reactants there and at the completion of the reaction when product formed. We always use the “Law of conservation of mass” when we balance chemical equations. 

Stoichiometry is further divided into two branches, which are-

1. Gravimetric Analysis

2. Volumetric Analysis

In Stoichiometry calculations we used different formulas and rules like-

• Formula Used in Gravimetric Analysis

• Formula Used in Volumetric Analysis

Chemical Test

In Chemistry, Chemical Test are performed to measure or analyze Biochemical, Organic and Inorganic elements and chemical compounds. Chemical testing of water, chemical composition analysis of any compound, chemical test for organic compounds, chemical test for inorganic compounds, chemical test for functional groups, elemental analysis, chemical testing of food for its ingredients and to detect presence of any sort of insecticide pesticide in it, chemical test perform in chemistry labs etc are the some examples where we perform chemical tests. Now we think you have now somewhat idea to give answer of question what is chemical test?

What is Chemical Test

In the scientific field of chemistry, chemical tests are the methods to detect the presence and amount of chemical compound or chemical group with the help of some chemicals or reagent. Chemical tests are performed according to chemical testing methods in chemical testing labs for elemental analysis and chemical composition analysis.

Chemical Test Definition

Chemical test is a qualitative or quantitative method intended to confirm the presence and amount of a chemical compound or chemical group with the help of chemicals or specific reagent.

Chemical Testing Methods

Chemical testing methods are step by step procedure to perform some sort of chemical tests. These procedures are written and proven for its quality testing to deliver results with high accuracy. Generally chemical testing labs have SOPs (Standard Operating Procedures), these SOPs provide step by step guidance to a chemist to perform specific test.

Chemical Analysis Methods

Their are so many chemical analysis methods, below is the list of some of them-

Acid Test 

                Test which are performed with the help of acids like Acid Test of Gold.

Barfoed's Test 

                      It is a chemical test performed to detect the presence of monosaccharides in the sample

Bromine Test 

                  In organic chemistry, It is a qualitative test to detect the presence of unsaturation ( means carbon-to-carbon double bonds or carbon-to-carbon triple bonds) and phenols.

Carbylamine Reaction

It is also known as Hoffman's Isocyanide Test. This chemical test is performed to detect primary amines.

Flame Test

                In inorganic chemistry, Flame test is performed to detect metals, elements or chemical compounds as they produce some characteristic colors.

Test

Test

What is Test

Test is a method to know about knowledge and ability of person giving test. Test meaning assessment about knowledge of someone on some topics related to test.

Test Definition

In short and simple way, we can say that, "Test is measure of knowledge and ability"

Their is so many tests which we can face in our life like classroom tests to know your knowledge about your study subjects, chemical test for chemical analysis, medical tests for medical fitness and disease diagnosis, physical tests, mental test, IQ test etc.

Chemical Test

In Chemistry, Chemical Test are performed to measure or analyze Biochemical, Organic and Inorganic elements and chemical compounds. Chemical testing of water, chemical composition analysis of any compound, chemical test for organic compounds, chemical test for inorganic compounds, chemical test for functional groups, elemental analysis, chemical testing of food for its ingredients and to detect presence of any sort of insecticide pesticide in it, chemical test perform in chemistry labs etc are the some examples where we perform chemical tests. READ MORE... 

Chemistry All Formulas

Periodic Table

Dynamic Periodic Table
Periodic Table PDF

What is Periodic Table ?

Periodic table is arrangement of chemical elements in the form of table. According to order of their atomic number, electronic configuration or chemical properties.

Why we need Periodic Table ?

Their was more than 115 elements have been discovered, which need to be arranged systematically.

How scientists arranged elements in Periodic Table ?

Scientists work hard to arrange elements in periodic table, today's periodic table is the result of different historical arrangements... 

History of classification of elements

     1.     Prout’s Hypothesis – 1815

     2.     Dobereiner’s Triads – 1829

     3.     Newland’s Law of Octaves – 1863

     4.     Lother Meyer Curves – 1869

     5.     Mendeleev’s Periodic Table – 1869

     6.     Modern Periodic Laws of Moseley -1913 

     7.     Modern Periodic Table ( of 18 columns ) 
  

Prout’s Hypothesis

                              According to this hypothesis atomic mass of elements is multiple of mass of hydrogenatom. So elements are related to each other on the basis of their atomic masses. It fails due to the reason that some elements do not have atomic mass in whole no. (Like chlorine have atomic mass of 35.5).

Dobereiner’s Triads

                                According to Dobereiner’s triads elements arranged in the group of three elements so that atomic mass of central element is appropriate mean of 1^st and 3^rd element. These groups of three elements are known as Dobereiner’s triads.

Example-

Element                                                           
 Li                Na                  K

Atomic Mass                                              
7                 23                  39

Mean of Atomic Masses of 1^st and 3^rd elements  is (7+39)/2  =   46/2   =  23

Newland’s Law of Octaves

According to Newland’s Law of Octaves elements arranged in the group of 8 elements and every 8^th element is similar to the 1^st element.

Li         Be         B        C          N         O           F

Na        Mg       Al        Si         P          S          Cl 

Lother Meyer Curves

                                       In 1869, Lother Meyer derived following conclusion by obtaining information from graph between the atomic weight at x-axis and atomic volume at y-axis.

      1.     Elements which have similar properties found on the same position on the graph curves.

      2.     All alkali metals like Li, Na, K, Rb, Cs, and Fr found at highest peak of curve.

      3.     Halogens like F, Cl, Br and I are found on ascending portion of curve.

      4.     Alkaline earth metals like Mg, Ca, Sr, Ba and Ra are found on descending portion of curve.

      5.     Elements which do not melt easily like Be, B, C, Al, Si, Cu etc. are found at lowest point of curve.

On the basis of above conclusions Lother Meyer give periodic Law:

                                                                                                  According to Lother Meyer periodic law – “Atomic volume of elements are periodic function of their atomic weights”.

Periodic Table

                        To classify elements a chart is prepared in which elements are arranged in rows and columns. These elements are arranged in table in such a way that the elements with similar properties are repeat after some intervals; also elements with similar properties are put in same column below one another. In periodic table vertical columns are called group while horizontal rows are called periods. In periodic table this repetition of properties in regular interval is known as periodicity. Read below chemistry notes of periodic table like Mendeleev periodic table, Mosley periodic table, Modern periodic table etc.

Mendeleev’s Periodic Table

                                                In Mendeleev’s Periodic Table, Mendeleev classify elements according to their atomic masses and arranged these elements in table according to their increasing order of atomic masses.

Mendeleev’s Periodic Law

                                                According to Mendeleev’s Periodic Law – “Physical and chemical properties of elements are periodic function of their atomic masses”.

Mendeleev’s Periodic Table contains seven horizontal rows known as periods and nine vertical columns known as groups.

Modern Periodic Table

                                   Moseley in 1913, after doing many experiments comes to a conclusion that the elements should be arranged as per their atomic no. and not according to atomic masses. As atomic no. is fundamental property of all elements of periodic table. So Mosley gives a new law which is called is Modern Periodic Law.

Modern Periodic Law

                                According to Modern Periodic Law- “Physical and Chemical properties of elements are periodic function of their atomic numbers”.

Long Form of Periodic Table

                                          Bohr Bury invented new periodic table, which is called as Long Form of Periodic Table. This Long Form of Periodic Table is also known as Modern Periodic Table.

Special features of Modern or Long Form of Periodic Table

These below are Special features of Modern or Long Form of Periodic Table

      I.     18 vertical columns known as groups.

      II.     Horizontal rows known as periods.

     III.     Light metals – These are elements of periodic table of group 1 and 2.

     IV.     Heavy metals or Transition metals - These are elements of periodic table of group 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12.

     V.     Non-Metals – These are elements of periodic table of group 13, 14, 15, 16 and 17.

     VI.     Zero group – These are elements of periodic table of group 18.

Definition

DEFINITION

What is Definition ?

Definition is a way to explain something to someone in short and sweet manner, means you define or explain some word, phrase or term which is not easily understood by everyone. We can also say that definition is a statement which describes a term, word or phrase by explaining all about it. 

Now question is where and how this word "Definition" is used ?

This word "Definition" is used in many ways to learn or to get information about some terms, words and phrases in science like...

Example1

Definition of pH
                   pH is negative logarithm of hydrogen ion concentration.
                   pH = -log10[H+]

Example2
Define Matter
                 Anything that has mass and takes up space.

Example3

Definition of Science
              Science is a branch of knowledge based on practicals, facts, truth, principles, laws and experiments to understand physical and natural world around us.

Example4

Definition of Chemistry
Chemistry is the scientific study of matter and substances for how they combine, separate, react or interact with each other. 

Now We think you understand what is "Definition" and how and where to use it... 

This post is for "Science For Kids"