chemistry lecture

1. CHEMISTRY
FOR TEXTILE
1. Basic concepts
L1: Measurement
Basicconcepts
1

2. MEASUREMENT
 In study of science we
frequently encounter
such properties of
materials which are to
be assessed
quantitatively. A few
examples of such
properties are weight,
length, volume,
temperature, voltage
etc.
Basic concepts 2

3. PHYSICAL PROPERTEIS OF
MATERIALS
Mechanical properties
 Tensile Strength
 Shear strength
 Fatigue
 Impact strength
 Bursting strength
 Tear Resistance
 Hardness
 Abrasion Resistance
 Peel strength
Basic concepts 3

4. PHYSICAL PROPERTIES OF
TEXTILE MATERIALS
 Thermal properties
 Thermal conductivity
 Heat capacity
 Optical properties
 Reflection
 Refraction
 Electrical properties
 Chemical resistance
 Weathering
 Washing fastness
 Light fastness
 Rubbing fastness
Basic concepts 4

5. HOW WE MEASURE
 We measure quantities
using a suitable unit and
measuring instrument.
 For e.g. to measure 1
liter of milk we can use a
measuring jug.
Basic concepts 5

6. UNITS OF MEASUREMENT
BASIC UNITS IN METRIC
SYSTEM
Mass
Length
Volume
Time
Temperatue
Energy
Amount of
substance
Basic concepts 6
 Kilogram
 Meter
 Liter
 Second
 Kelvin
 joule
 Mole
 Second

7. MASS
 There many units for
measuring mass.
 There are also smaller
and larger units of each
units.
Basic concepts 7
Kilogram
Gram
Milligram
Microgram

8. LENGTH
 Unit of length in SI
system is “meter”.
 There super and sub
units of meters to
measure larger and
smaller articles.
Basic concepts 8

9. VOLUME
 Volume can be measured
in liter, pound, gallon
and many other units.
 SI unit of volume is liter.
Basic concepts 9

10. MORE UNITS
 Force
 Pressure
 Work
 strength
 Current
 EMF
 light
Basic concepts 10
 Newton
 Kg/m2
 Newton - meter
 Kg/cm2
 Ampere
 Volt
 Candela

11. UNCERTAINTY IN
MEASUREMENT
 Measurement of any
property is made using
an instrument which
always has some
limitations.
 This weighing balance
cannot measure any
quantity smaller than
0.1 mg.
Basic concepts 11

12. UNCERTAINTY IN MEASUREMENT
Basic concepts 12
 Burette is used to
measure volume of
liquid. In a 50 ml burette
distance between two
lines measure 0.1 ml.
Any quantity smaller
than 0.1 ml cannot be
measured on this burette
with accuracy.

13. UNCERTAINTY IN MEASUREMENT
 In case of
burette if the
meniscus of
liquid stays
between two
lines, accurate
measurement
cannot be
made.
Basic concepts 13

14. SIGNIFICANT FIGURES
 To show and understand
uncertainty in measuremet
the results of any
measurement are expressed
mathematically up to a
certain number of decimal
digits. These decimal digits
are called significant figure.
 Depending on the accuracy
required, the number of
decimal digits varies.
Basic concepts 14
 0.1
 0.01
 0.001
 .0001
 Etc.

15. CONVERSION OF UNITS
 There are different
types of units in use
throughout the world.
 One type of units can
be converted to
another type which is
equivalent to the
previous one.
 Kilometers to miles
 Meter to yard
 Centimeters to inches
 Kg and g to pound
 Liter to gallons
 ml to liquid ounce
 Centigrade to
fahrenheight
Basicconcepts
15

16. CONVERSION FACTORS
 Conversion factor is a
mathematical figure
which converts a
quantity in certain
measurement system
to units of another
measurement system.
Basicconcepts
16
 1 kg = 2.2005 lb
 Hence to convert kg to
pound, the number of
kg’s must be
multiplied by 2.2005
for example:
 2 kg is = (2 x 2.005
= 4.014 lb)

17. CONVERSION FACTORS
 Temperature in
degree centigrade can
be converted to
fahrenheight
 °C to °F
°F = 9/5 x °C + 32
 °F to °C
°C = 5/9 x (°F – 32)
Basicconcepts
17

18. CONVERSION FACTORS
 Energy in Joule can
be converted to calorie
and vice versa
 1 cal = 4.184 J
Basicconcepts
18

19. CONVERSION FACTORS
 Length in meters and
kilometers can be
converted to feet,
yards or miles
 1 meter = 39 inches
Basicconcepts
19

20. ATOMIC AND MOLECULAR WEIGHT
 Atomic weight is in
fact not a weight. This
is in fact a comparison
of the size of atoms.
 In the same way
molecular weight is
the total of atomic
weights of all the
atoms in a molecule.
Basicconcepts
20

21. EQUIVALENT WEIGHT
Basicconcepts
21