CHAPTER 1- Basic of Chemistry for introduction

Basic of Chemistry level

1. CHAPTER 1:
UNITS OF
MEASUREMENTS

2. Matteris anything that occupies space and has
mass.
A substanceis a form of matter that has a
definite composition and distinct properties.
Chemistryis the study of matter and the
changes it undergoes
liquid nitrogen gold ingots silicon crystals

3. DIMENSIONS
Defined as:
Any physical quantities that can be measured by measuring devices.
There are 2 types of dimension:
1.Basic dimension
oThe simplest and the most basic physical quantities
oThere are 7 basic dimensions:
-length
-mass
-time
-temperature
-amount of substances
-luminous intensity
-electrical current

4. 2. Derived dimensions
oPhysical quantities that are obtained by combining basic
physical by multiplying / dividing the basic dimensions.
Derived dimensions Combination of Basic
dimensions
Area Length x length
Volume Length x length x length
Speed Length / time
Force (mass x length) / (time x time)
Density Mass / (length x length x
length)
Pressure Mass / (time x time)

5. International System of Units (SI)

6. S.I system of units
Dimension
Symbol of
dimension
Name of unit Symbol of unit Definition of unit
Basic SI Units
length L meter m
mass m kilogram Kg
time t second s
temperature T Kelvin, degree celcius K, °C
Amount of
substance
n mole mol
Derived SI Units
Energy E Joule J / Nm Kg.m
2
.s
-2
Force F Newton N Kg.m.s
-2
Power P watt W /J/s Kg.m
2
.s
-3
Velocity V Meter per second m.s
-1
Acceleration a Meter per second
squared
m.s
-2
Pressure P Newton per meter
squared,
Pascal
N.m
-2
Pa
Density ƿ Kilogram per cubic
meter
Kg.m
-3

7. American Engineering system of units
Dimension
Symbol of
dimension
Name of unit Symbol of unit Definition of unit
Basic SI Units
length L Feet ft
mass m Pound mass Ibm
force F Pound force Ibf
time t Second S
temperature T Degree Rankie,
Degree Fahrenheit
°R
°F
Amount of
substance
n mole Ib mol
Derived SI Units
Energy E Foot pound force Ft.Ibf
Force F Pound force Ibf
Power P Horsepower hp
Velocity V feet per second ft.s
-1
Acceleration a feet per second
squared
ft.s
-2
Pressure P Pound force per
second inch
Psi
Density ƿ Pound mass per cubic Ibm.ft
-3

9. Matter -anything that occupies space and has
mass.
mass–measure of the quantity of matter
SI unit of mass -kilogram(kg)
1 kg = 1000 g = 1 x 10
3
g
MASS

10. Volume–SI unit for volume is cubic meter
(m
3
) 1 cm
3
= (1 x 10
-2
m)
3
= 1 x 10
-6
m
3
1 dm
3
= (1 x 10
-1
m)
3
= 1 x 10
-3
m
3
1 L = 1000 mL = 1000 cm
3
= 1 dm
3
1 mL = 1 cm
3
VOLUME

11. Density–SI unit for density is kg/m
3
1 g/cm
3
= 1 g/mL = 1000 kg/m
3
density =
mass
volume
d=
m
V
A piece of platinum metal with a density of 21.5 g/cm
3
has a volume of 4.49 cm
3
. What is its mass?
d=
m
V
m= dx V= 21.5 g/cm
3
x 4.49 cm
3
= 96.5 g
DENSITY
EXAMPLE:
OR

13. K = (
o
C + 273.15
o
C) x 1 K
Temperature
•Three temperature scales:
i)
0
F –degrees Fahrenheit
ii)
0
C –degrees Celcius
iii)K -Kelvin
o
F = x
o
C + 32
o
F
9
o
F
5
o
C
o
C = (
o
F –32
o
F) x
5
o
C
9
o
F
•Measurement of how hot/cold a substance is
relative to another substance.
1
o
C

14. Convert 172.9
0
F to degrees Celsius.
0
C = x (
0
F –32)
9
5
0
C = x (172.9 –32) = 78.3
9
5
Example:

15. Scientific Notation
The number of atoms in 12 g of carbon:
602,200,000,000,000,000,000,000
6.022 x 10
23
The mass of a single carbon atom in grams:
0.0000000000000000000000199
1.99 x 10
-23
N x 10
n
N is a number
between 1 and 10
nis a positive or
negative integer

16. 568.762
n > 0
568.762 = 5.68762 x 10
2
move decimal left
0.00000772
n < 0
0.00000772 = 7.72 x 10
-6
move decimal right
Addition or Subtraction
1.Write each quantity with the same exponent n
2.Combine N
1and N
2
3.The exponent, n, remains the same
4.31 x 10
4
+ 3.9 x 10
3
=4.31 x 10
4
+ 0.39 x 10
4
= 4.70 x 10
4

17. Multiplication
1.Multiply N
1and N
2
2.Add exponents n
1and n
2
(4.0 x 10
-5
) x (7.0 x 10
3
) = ?
= (4.0 x 7.0) x (10
-5+3
)
= 28 x 10
-2
= 2.8 x 10
-1
Division
1.Divide N
1and N
2
2.Subtract exponents n
1and n
2
8.5 x 10
4
÷5.0 x 10
9
= ?
= (8.5 ÷5.0) x 10
4-9
= 1.7 x 10
-5
(a x 10
m
) x (b x 10
n
) = (axb) x 10
m+n
(a x 10
m
) ÷(b x 10
n
) = (a ÷b) x 10
m-n

18. Significant Figures
-The meaningful digits in a measured or calculated
quantity.
RULES:
•Any digit that is not zero is significant
1.234 kg 4 significant figures
•Zeros between nonzero digits are significant
606 m 3significant figures
•Zeros to the left of the first nonzero digitare not
significant
0.08 L 1significant figure
•If a number is greater than 1, then all zeros to the
right of the decimal pointare significant
2.0 mg 2significant figures

19. •If a number is less than 1, then only the zeros
that are at the end and in the middle of the
number are significant
0.00420 g 3significant figures
•Numbers thatdo not contain decimal points,
zeros after the last nonzero digit may or may not
be significant.
400 cm 1or 2 or 3significant figures
4 x 10
2
1significant figures
4.0 x 10
2
2 significant figures

20. How many significant figures are in each of
the following measurements?
24 mL 2 significant figures
3001 g 4 significant figures
0.0320 m
3
3 significant figures
6.4 x 10
4
molecules 2 significant figures
560 kg 2 significant figures

21. Significant Figures
Addition or Subtraction
The answer cannot have more digits to the right of the
decimal pointthan any of the original numbers.
89.332
1.1+
90.432 round off to 90.4
one significant figure after decimal point
3.70
-2.9133
0.7867
two significant figures after decimal point
round off to0.79

22. Significant Figures
Multiplication or Division
The number of significant figures in the result is set by
the original number that has the smallestnumber of
significant figures
4.51 x 3.6666 = 16.536366= 16.5
3 sig figs round to
3 sig figs
6.8 ÷112.04 = 0.0606926
2 sig figs round to
2 sig figs
= 0.061

23. Significant Figures
Exact Numbers
Numbers from definitions or numbers of objects
are considered to have an infinite number of
significant figures
The average of three measured lengths; 6.64, 6.68
and 6.70?
6.64 + 6.68 + 6.70
3
= 6.67333 = 6.67
Because 3 is an exact number
= 7

24. Dimensional Analysis Method of Solving
Problems
Conversion Unit 1 L = 1000 mL
1L
1000 mL
1.63 L x = 1630 mL
How many mL are in 1.63 L?

25. The speed of sound in air is about 343 m/s. What
is this speed in miles per hour?
1 mi = 1609 m 1 min = 60 s 1 hour = 60 min
343
m
s
x
1 mi
1609 m
60 s
1 min
x
60 min
1 hour
x = 767
mi
hour
meters to miles
seconds to hours
conversion units

26. TUTORIAL
1)Give the SI unit for expressing the following
a) Length b) Mass c) Volume
d) Time e) Temperature
2)Write the numbers represented by the following prefixes
a) mega b) deci c) mili
d) nano
3) The density of ethanol is 0.798 g/mL. Calculate the mass of 17.4
mL of the liquid.
4) Convert the following temperatures to Kelvin, K.
a) 113
o
Cb) 37
o
C c) 357
o
C
5) Express the following numbers in scientific notation
a) 0.000047 b) 35900 c) 0.0411
6) How many scientific figures are there in each of the following
a) 0.0605 dm b) 60.5 m c) 60 m
d) 4.715 kg e) 0.0051 g