Chem chap 2
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what is scientific notation
standard way of expressing large as well as small number
 (large) greater than 1
 (small) less than 1

What is measurement?
quantative observation  value number with a unit ex] length 225cm

(Standard notation)  exponential notation
 decimal  between 1 & 10
 exponential part (10^x)

Rules of expressing a number in scientific notation
  Move the decimal to get a number between 1&10
 When decimal is moved to left, the power is positive
  when decimal is moved to right, the power is negative

expressing using scientific notation
100.50
0.0380
5
100.
100
 1.0050 * 10^2
 3.80 * 10^2
 5 *10^0
 1.00 * 10^2
 1 * 10^2

Significant figures
 (digits) (sf) reflects precision of a given number
 greater the number of sf, greater is its precision

100
100.
100.0
100.00
 1sf
 3sf
 4sf
 5sf (highest precision)

Rules of counting (sf) of a given number
 all non zero digits are significant
 leading zeros(zeros before a nonzero digit) are not significant ex] 0.000058 (2sf)
  interior zeros (zeros after a nonzero digit) are significant ex] 100,005.78 (8sf)
  trailing zeros (zeros after a nonzero digit) are significant, provided the number given with a decimal point

100
100.
100.00
0.00100500
100.500

Exact number
 number with unlimited sf.
 numbers reported by counting discrete objects
 ex] 30.0000 students 30 students unlimited sf
 numbers of a defined quantities
 ex] 1m=100cm 1.000000m=100.0000 cm

Rounding off number
 if digit is 4 or less, it is rounded down
 if digit is 5 or more, it is rounded up
 proceeding digit is increased by one

Rules of sf in calculations
The answer should be least precise as possible

Multiplication and Division
The answer should be least sf as possible

Rules of sf for addition and subtraction
The answer of least decimal places as possible

MeasurementQuantitative observation
Contains a number value and a unit

Units
 standard agreed upon quantities by which measurements are made
 (english unit)
 (metric unit)
 (scientist use SI unit) follows metric system of units

Prefix Multipliers
 Tera T 10^12
 Giga G 10^9
 Mega M 10^6
 Kilo K 10^3
 deci d 10^1
 centi c 10^2
 milli m 10^3
 micro (mu) 10^6
 nano n 10^9
 pico p 10^12

SI units (standard) of measurement
 Lengthmeter m
 volume cubicmeter m^3
 mass  kilogram kg
 temperature kelvin K
 time seconds s

length is:
 measurement of distance between two points
 measured using a ruler

Length:
SI unit
Metric unit
English unit
 m
 km, m, mm, nm
 in, ft, yd, mile

Volume is:
 a measureof 3dimensional space occupied by an object
 is a derived measurements with units of length (raised to the power of 3)
 is measured using graduated cylinder

Volume:
SI unit
Metric unit
Eng unit
Common unit
laboratories
 m^3
 km^3, m^3, mm^3
 teaspoon, tablespoon, fl oz, cups, pints, gallon
 kL, L, cL, mL, (mu)L
 1mL=10^3L
1cm^3=1mL=1cc


Mass is
 a measure of quantity of material (matter)
 is measured using a balance

weight is
a measure of force of gravity acting up an object

Mass:
SI unit
metric unit
eng unit
 kg
 kg, mg, g, mu g
 oz., lb 16 oz. 1lb.

Unit conversion
 changing from one unit to another for particular measurement
 using conversion factors derived from equivalents

Density is:
a measure of mass per unit volume is the ratio of mass to volume
d=m/v

How to find V=
V= mass/ density
