Class 12 Chemistry Practical File

This is to certify that of
Class XII Science has successfully completed his
demonstration file on the topic “
in the Chemistry
Lab during year 2015-16.
Submitted for All India Senior Secondary
Certificate Practical Examination held in the
Chemistry Lab at DAV Public School, Unchahar,
Raebareli(U.P.).

“There are times when silence speaks so much more loudly than
Words of praise to only as good as belittle a person, whose words do
not express, but only put a veneer over true feelings, which are of
gratitude at this point of time.”
I wish to express my sincere gratitude and
special thanks to my respected Principal
“Mr. Vijay Kumar Chandel”, Chemistry
Teacher “Mr. Mohd. Imran” and
Laboratory Assistant “Mr. Subodh Choudhary”
for their timely help and valuable suggestion
without which my demonstration file would
not have been success.

To study the setting of
mixture of cement with sand,
time and fly ash with respect to
time and strength.

Beaker Glass Rod Weight Box
Match Box Cement Fly Ash
LimeStone River Sand
Page No. 6

In the most general sense of the word, CEMENT is
a binder, a substance that sets and hardens
independently, and can bind other materials
together.
The word “ cement “ traces to the Romans, who
used the term opus caementicium to describe
masonry resembling modern concrete that was made
from crushed rock with burnt lime as binder. The
volcanic ash and a pulverized brick additive that
were added to the burnt lime to obtain a hydraulic
binder were later referred to as cementum,
cimentum, cament and cement.
The most important use of cement is the
production of mortar and concrete The bonding of
natural or artificial aggregates to form a strong
building material that is durable in the face of
normal environment effects.
Page No. 7

Cement is made by heating Limestone (calcium
carbonate), with small quantities of other materials
(such as clay) to 1450°C in a kiln, in a process
known as calcination, whereby a molecule of carbon
dioxide is liberated from the calcium carbonate to
form calcium oxide, or quicklime, which is then
blended with the other materials that have been
included in the mix. The resulting hard substance,
called 'clinker', is then ground with a small amount
of gypsum into a powder to make 'Ordinary
Portland Cement', the most commonly used type
of cement (often referred to as 0PC).Portland
cement is a basic ingredient of concrete, mortar
and non-specialty grout. The most common use for
Portland cement is in the production of concrete.
Concrete is a composite material consisting of
aggregate (gravel and sand), cement and water. As
a construction material, concrete can be cast in
almost any shape desired and once hardened, can
become a structural (load bearing) element.
Portland cement may be gray or white.
Page No. 8

Cement used in construction is characterised as
hydraulic or non-hydraulic. Hydraulic cements (eg.
Portland cement) harden because of hydration
chemical reactions that occurs independently
Of the mixture's water content; they can harden
even underwater or when constantly exposed to
wet weather. The chemical reaction that results
when the anhydrous cement powder is mixed with
water produces hydrates that are not water-soluble.
Nonhydraulic cements (eg. Lime and gypsum
plaster) must be kept dry in order to retain their
strength.
Page No. 9

On the other hand, Pit sand is obtained
from pits in the soil and the River sand
obtained from riverbed is considered
excellent for preparing mortar and
concrete
Sand obtained from different sources has
different qualities. For example, Sea sand
obtained from sea contains unwanted
salts and retards setting of cement and is
not suitable for making mortar.
Page No. 11

Time has an important rote on strength
of developed cement mortar. When a
cement paste in the ratio 1:3 in water is
allowed to dry, the strength of solid mass
keeps on increasing with increase in time
given for setting. It acquires a nearly full
strength in 28 days.
Page No. 12

 Prepare mixtures of various compositions as given
in observation table.
 Take each of the given mixtures in different
beakers and prepare their pastes by adding
minimum amount of water
 Take nine cases of empty match boxes and mark
them from 1 to 9.
 Fill the three cases with the paste of each
composition.
 Spray water from time to time over the
paste ,so that they remain moist all the time.
 After three days, take out one slab of each
composition and test their strengths.
 Similarly, take out a set of three slabs after 7
days after 30 days respectively and test their
strengths.
Page No. 13

By seeing the observation we can estimate the hardness of
the slab.
Page No. 14

The strength of the slab Increases with
the Increase in setting time allowed.
Page No. 15

Handle the glass wares safely.
Allow the time required to set.
Spray only required amount of water.
Page No. 16

For analysis of this project I took the help from books and internet
sites mentioned below –
 Chemistry Practical Book – Class 12
 Information from Library
 www.icbse.com
 www.wikipidea.com
 www.google.co.in
 www.ukchemistry.com
Page No. 17

Class 12 Chemistry Practical File

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