مصادر الكيمياء موقع لتعليم الكيمياء بصورة مبسطة
INTRODUCTION TO CHEMISTRY NOTES
METRIC SYSTEM UNIT FOR:
1) Mass 2) Volume
3) Length 4) Time
1) gram
2) liter
3) meter
4) second
METRIC ABBREVIATIONS:
1) 1,000,000
2) 1000
3) 100
4) 10
1) mega
2) kilo
3) hecto
4) deka
EXPRESS:
1) 100 GRAMS
2) 1/10 LITER
3) 1000 METERS
4) 0.001 GRAMS
1) 1 hectogram
2) 1 deciliter
3) 1 kilometet
4) 1 miIIigram
METRIC SYMBOL: GRAM, METER, LITER
GRAM = g
METER = m
LITER = L
METRIC ABBREVIATIONS: MEGA, KILO, HECTO, DEKA, DECI, CENTI, MILLI, NANO
MEGA = M
KILO = k
HECTO = h
DEKA = dk
DECI = d
CENTI = c
MILLI = m
NANO = n
METRIC ABBREVIATIONS:
1) DECIGRAM
2) KILOLITER
3) HECTOMETER
4) MILLIGRAM
1) dg
2) kL
3) hm
4) mg
Notice which letters are capital and which aren’t.
CONVERSION FACTOR
A fraction which expresses an equality between two units of measurement and can be used to convert from 1 to the other. (Ex. 1 kg/1000 g)
CONVERSION FACTORS-
1. INCHES TO FEET
2. GRAMS TO KILOGRAMS
3. MILES TO KILOMETERS
1 foot / 12 inches
1 kilogram / 1000 grams
1 mile / 1.61 Km
USE CONVERSION F ACTORS TO SOL VE:
1. HOW MANY KILOGRAMS IN 2000 GRAMS?
2. HOW MANY FEET IN 60 INCHES?
1. (2000 g)(l kg/1000 g) = 2 kg
2. (60’’) X (l’/12’’) = 5 feet
SIGNIFICANT DIGITS
Digits which are measured.
All non-zero digits are significant.
Zeros are significant unless they are placeholders.
How many significant digits?
1) 300
2) 0.0020
3) 4006
4) 5.00
1) 300
2) 0.0020
3) 4006
4) 5.00
(SIGNIFICANT DIGITS UNDERLINED)
SCIENTIFIC NOTATION
A NUMBER EXPRESSED AS A x 10B
(A IS BETWEEN 1.00 AND 9.99 AND B IS AN INTEGER)
CONVERT TO SCIENTIFIC NOTATION
1) 695
2) 0.04
3) 3000
1) 6.95 x 102
2) 4 x 10-2
3) 3 x 103
CONVERT FROM SCIENTIFIC NOTATION
1) 1.23 x 104
2) 6 x 10-3
1) 12300
2) 0.006
CONVERSION FORMULAS:
1) CELSIUS TO FAHRENHEIT
2) CELSIUS TO KELVIN
1) °FAHRENHEIT = (1.8 x °CELSIUS) + 32
2) KELVIN = °CELSIUS+ 273
CONVERT:
1. 100° CELSIUS TO KELVIN
2. 30° CELSIUS TO °FAHRENHEIT
1. K = °C + 273
K = 100 + 273 = 373 K
2. °F = (1.8 x °C) + 32
°F = (1.8 x 30) + 32 = 86°F
ABSOLUTE ZERO VALUE IN KELVIN, CELSIUS AND FAHRENHEIT?
Lowest possible temperature where all atomic motion ceases.
0 K = -273° C = -460° F
1. SCIENTIFIC LAW
2. HYPOTHESIS
1. An event which occurs with unvarying regularity. Often expressed in a mathematical equation. Example: Einstein’s Law of Relativity: E = mc2
2. A tentative explanation of observations which requires further experimentation.It must be scientifically testable. Example: “You are the best dancer” is not testable.
1. ENERGY
2. MATTER
1. The ability to do work; it is released or absorbed during chemical reactions in the form of heat, light, electricity. ( calorie, Joule: 1 cal = 4.18J)
2. A substance that occupies space and has mass.
WEIGHT AND MASS
Mass is the amount of matter.
Weight measures gravitational force. Mass never varies; weight does.
POTENTIAL ENERGY AND KINETIC ENERGY
Potential Energy is energy due to position or stored energy.
Kinetic Energy is energy of motion.
A rock an top of a hill has potential energy. As it falls it has kinetic energy.
METRIC ABBREVIATIONS:
SECONDS, CELSIUS, KELVIN, MOLES, AMPERES
SECONDS – S
CELSIUS – °C
KELVIN – K
MOLES – mol
AMPERES – A
METRIC PREFIXES FOR:
1) 0.1
2) 0.01
3) 0.001
4) 0.000000001
1) deci
2) centi
3) milli
4) nano
WHAT ARE THE VOLUME AND MASS OF WATER AT 4° CELSIUS?
At 4 °C water is at maximum density.
1 g occupies 1 ml or 1 cm3. Therefore, 1 liter weighs 1 kg.
COMP ARE FREEZING AND BOILING POINTS OF WATER IN THESE TEMPERA TURE SCALES. CELSIUS, KELVIN, FAHRENHEIT
° F freezing : 32
boiling: 212
° C freezing: 0
boiling: 100
° K freezing: 273
boiling: 373
1. Explain how to convert a number greater than 1 to scientific notation.
2. Explain how to convert a number less than 1 to scientific notation.
1. Move decimal point to left until only 1 digit remains to left. Indicate number of moves as a positive exponent of 10. (3301 = 3.301 x 103)
2. Move decimal point to right until only 1 digit remains to left. Indicate number of moves as a negative exponent of l 0. 0.00356 = 3.56 x 10-3
1. Explain the rules for multiplication of numbers in scientific notation.
2. Explain the rules for division of numbers in scientific notation.
1. Multiply the first numbers and add the exponents.
(3 x 105)(2 x 103) = 6 x 108
2. Divide the first numbers and subtract the exponents.
(8 x 106) / (2 x 1010) = 4 x 10-4
COMPARE: PRECISION AND ACCURACY
precision- the reliability or reproducibility of a measurement
accuracy- how close a measurement is to the accepted value
DEGREE OF UNCERTAINTY
The uncertainty in a measurement depends on the skill of the person doing the measuring and the limitations of the measuring instrument. The last significant figure in a measurement is always uncertain.
METRIC UNITS FOR:
1) TEMPERATURE
2) ELECTRIC CURRENT
3) AMOUNT OF SUBSTANCE
1) Celsius or kelvin
2) ampere
3) mole