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Application of mole concept requires a balanced chemical equation. The different constituents of the reaction – reactants and products – bear a simple whole number proportion same as the proportion of the coefficients associated with constituents. According to mole concept, the molar mass of constituents participates in this proportion. For a generic consideration as given :

x A + y B A x B y

Here, 1 mole of compound ( A x B y ) involves x mole of A and y mole of B. Using symbols :

x moles of A y moles of B 1 mole of A x B y

The point to emphasize here is that this is a relation, which is connected by "equivalence sign (≡)" - not by "equal to (=)" sign. We know that 2 moles of hydrogen reacts with 1 mole of oxygen to form 2 moles of water. Clearly, we can not equate like 2=1=2. We need to apply unitary method to interpret this relation of equivalence. We say that since x moles of A react with y moles of B. Hence, 1 mole of A reacts with y/x moles of "B". Similarly, 1 mole of B reacts with x/y moles of "A". Once we know the correspondence for 1 mole, we can find correspondence for any other value of participating moles of either A or B.

Mass of participating entities in a reaction

Mole concept is used to calculate mass of individual constituent of a chemical reaction. The proportion of molar mass is converted to determine proportion of mass in which entities are involved in a reaction. The symbolic mass relation for the chemical reaction as given above is :

x M A gm of A y M B gm of B M A x B y gm of A x B y

We apply unitary method on the mass relation related with equivalent sign (≡) to determine mass of different entities of the reaction.

Problem : Calculate mass of lime (CaO) that can be prepared by heating 500 kg of 90 % pure limestone ( C a C O 3 .

Solution : Purity of CaCO3 is 90 %. Hence,

Mass of C a C O 3 = 0.9 X 500 = 450 k g

The chemical reaction involved here is :

C a C O 3 C a O + C O 2

Applying mole concept :

1 mole of C a C O 3 1 mole of CaO

(40 + 12 + 3X 16) gm of C a C O 3 (40 + 16) gm of CaO

100 gm of C a C O 3 56 gm of CaO

100 kg of C a C O 3 56 kg of CaO

Applying unitary method :

mass of CaO produced = 56 X 450 100 = 252 k g

Problem : Igniting M n O 2 converts it quantitatively to M n 3 O 4 . A sample of pyrolusite contains 80% M n O 2 , 15 % S i O 2 and 5 % water. The sample is ignited in air to constant weight. What is the percentage of manganese in the ignited sample ? ( A M n = 55 )

Solution : The sample contains three components. Since this question involves percentage, we shall consider a sample of 100 gm. Water component weighing 5 gm evaporates on ignition. S i O 2 weighing 15 gm does not change. On the other hand, 80 gm of M n O 2 converts as :

3 M n O 2 M n 3 O 4 + O 2

Applying mole concept,

3 moles of M n O 2 1 mole of M n 3 O 4

3 X 55 + 2 X 16 gm of M n O 2 1 X 3 X 55 + 4 X 16 gm of M n 3 O 4

261 gm of M n O 2 229 gm of M n 3 O 4

Since sample is ignited in air to constant weight, it means that all of Mn O 2 in the sample is converted. Using unitary method, we determine mass of converted mass of M n 3 O 4 for 80 gm of Mn O 2 :

Mass of M n 3 O 4 on conversion = 229 261 X 80 = 70.2 g m

We are required to find the percentage of Mn in the ignited sample. Thus, we need to determine the mass of the ignited sample. The ignited sample contains 70.2 gm of M n 3 O 4 and 15 gm of S i O 2 . Total mass of ignited sample is 70.2+15 = 85.4 gm. On the other hand, amount of Mn in M n 3 O 4 is calculated from its molecular constitution :

229 gm of M n 3 O 4 3 X 55 gm of Mn 165 gm of Mn

Amount of Mn in 70.2 gm of M n 3 O 4 = 165 229 X 70.2 = 0.72 X 70.2 = 50.54 g m

Clearly, 85.4 gm of ignited sample contains 50.54 gm of Mn. Hence,

Percentage amount of manganese in the ignited sample = 50.54 85.4 X 100 = 59.2 %

Questions & Answers

how can chip be made from sand
Eke Reply
is this allso about nanoscale material
are nano particles real
Missy Reply
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
where is the latest information on a no technology how can I find it
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
has a lot of application modern world
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
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Source:  OpenStax, Stoichiometry. OpenStax CNX. Jul 05, 2008 Download for free at http://cnx.org/content/col10540/1.7
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