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El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY 21ASurvey of General and Organic Chemistry
Dr. Dragan [email protected]
Spring Semester 2009
El Camino College, Torrance, CA
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY
H2O, NaCl
Systematic (IUPAC) name
(2α, 4α, 5β, 7β, 10β, 13α)- 4, 10- bis(acetyloxy)- 13- {[(2R, 3S)- 3- (benzoylamino)- 2- hydroxy- 3- phenylpropanoyl] oxy}- 1, 7-
dihydroxy- 9- oxo- 5, 20- epoxytax- 11- en- 2- yl benzoate
TAXOL® (paclitaxel)
water table salt
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRYMedicines containing derivatives of salicylic acid, structurally similar to aspirin, have been in medical use since ancient times. Salicylate-rich willow bark extract became recognized for its specific effects on fever, pain and inflammation in the mid-eighteenth century.
In 1897, scientists at the drug and dye firm Bayer began investigating acetylsalicylic acid as a less-irritating replacement for standard common salicylate medicines. By 1899, Bayer had dubbed this drug Aspirin and was selling it around the world. The name Aspirin is derived from A = Acetyl and "Spirsäure" = an old (German) name for salicylic acid.
At the beginning of 20th century heroin was touted as a wonder drug promising to solve all of life's maladies ranging from tuberculosis to a disagreeable stomach.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
Question: What Is Chemistry?
Answer: If you look 'chemistry' up in Webster's Dictionary, you'll see:
"chem·is·try n., pl. –tries”
1. the science that systematically studies the composition, properties, and activity of organic and inorganic substances and various elementary forms of matter.
2. chemical properties, reactions, phenomena, etc.: the chemistry of carbon.
3. a. sympathetic understanding; rapport. b. sexual attraction.
4. the constituent elements of something; the chemistry of love.
CHEMISTRY
El Camino College Chemistry 21A Dr. Dragan Marinkovic
Chemistry (from Egyptian kēme (chem), meaning "earth“
1)Chemistry is the science concerned with the composition, structure,
and properties of matter, as well as the changes it undergoes
during chemical reactions.
2) Chemistry is a physical science for studies of various atoms, molecules, crystals and other aggregates of matter whether in isolation or
combination, which incorporates the concepts of energy and
entropy in relation to the spontaneity of chemical processes.
Modern chemistry evolved out of alchemy after the
chemical revolution (1773)
CHEMISTRY
El Camino College Chemistry 21A Dr. Dragan Marinkovic
Disciplines within chemistry include
Inorganic chemistry, the study of inorganic matter
Organic chemistry, the study of organic matter
Biochemistry, the study of substances found in
biological organisms
Physical chemistry, the energy related studies of
chemical systems at macro, molecular and
submolecular scales
Analytical chemistry, the analysis of material samples to
gain an understanding of their chemical composition
and structure.
Medicinal or pharmaceutical chemistry is a discipline
at the intersection of chemistry and pharmacology involved with designing, synthesizing and developing pharmaceutical drugs.
CHEMISTRY
El Camino College Chemistry 21A Dr. Dragan Marinkovic
Why Study Chemistry?
Because understanding chemistry helps you to understand the world around you. Cooking is chemistry. Everything you can touch or taste or smell is a chemical.
When you study chemistry, you come to understand a bit about how things work.
Chemistry isn't secret knowledge, useless to anyone but a scientist.
It's the explanation for everyday things, like why laundry detergent works better in hot water, or how baking soda works, or why not all pain relievers work equally well on a headache.
If you know some chemistry, you can make educated choices about everyday products that you use.
CHEMISTRY
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY 21A
The real importance of Chemistry is that it serves as the interface to practically all of the
other sciences, as well as to many other areas of human endeavor.
For this reason, Chemistry is often said (at
least by chemists!) to be the "central science".
Chemistry can be "central" in a much more
personal way: with a solid background in Chemistry, you will find it far easier to
migrate into other fields as your interests develop.
Chemistry: the central science
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY
HEALTH SCIENCES
NUTRITION
MICROBIOLOGY
BOTANY
PHYSIOLOGY
MATERIALS SCIENCE
CHEMISTRY
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY 21A
Chemistry 21A is the first semester of a two-semester sequence designed to provide students with the skills and knowledge needed to satisfy the requirements for several allied health related majors, especially the pre-Nursing major. This course presents the fundamental principles of inorganic chemistry and begins the study of organic chemistry.
Chemistry 21A fulfills the chemistry prerequisite for Biology 1B, Microbiology 33, and Physiology 31, and provides the foundation necessary for success in Chemistry 21B (the second course in the sequence).
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY 21AMaterials:1 . Seager and Slabaugh, Chemistry for Today: General, Organic, and Biochemistry, 6th Ed.
2. Campbell, Chemistry 21A Packet
3. Peller, Exploring Chemistry: Laboratory Experiments in General, Organic, and Biological Chemistry, 2nd Ed.
4. Safety goggles (Instructor approved - do not purchase until "fitted" in class)
5. Calculator (able lo handle exponential notation calculations and logarithms)
6. OPTIONAL: Study Guide and Solutions Manual for Seager and ,Slabaugh's Chemistry for Today: General, Organic, and Biochemistry 5th Ed.
7. A set of different colored pens or pencils is recommended for note taking!
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY 21A
Grading: Final letter grades will generally be assigned according to the following percentage of total points
earned:
Grade -- Percent A 90 - 100% B 80 - 90% C 65 - 80% D 55 - 65% F below 55%
Approximate distribution of points:Tests (3 @ 100 points each) ...........................................
300Quizzes (9 @ 20 points each) .........................................
180Laboratory (total points) .................................................
240Assignments/Other ................................... . ...................
30Final Exam ..................................................................
250Course Total ..................................................................
1000
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY 21A
Is it possible to do lots of hard work and have fun at the same time?
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY 21A
Is it possible to do lots of hard work and have fun at the same time?
Maybe?
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY 21A
Is it possible to do lots of hard work and have fun at the same time?
Maybe?
Maybe not?
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY 21A
But, we can certainly try and make the best of this very scientific course.
You will have to learn many new definitions, visualize many abstract concepts and start thinking like a scientist.
I compare learning chemistry to learning a foreign language. You have to learn words before you can speak. So, new chemical words are waiting for you!
I’ll try my best and I expect you will try your best too!
I am here to help you learn, and I MEAN IT! Let me know how I can help you learn.
Is it possible to do lots of hard work and have fun at the same time?
Maybe?
Maybe not?
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY 21A
I am here to help you learn, and I MEAN IT! Let me know how I can help you learn.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY 21A
I am here to help you learn, and I MEAN IT! Let me know how I can help you learn.
However, I am not going to give out “easy passes”.
Please, be prepared and ready for work.
Be attentive. (No cell phones, video games,snacks or fixing make-up during classes!)
Ask relevant questions!
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CHEMISTRY 21A
I am here to help you learn, and I MEAN IT! Let me know how I can help you learn.
I am here to help you learn, and I MEAN IT!
Let me know how I can help you learn.
However, I am not going to give out “easy passes”.
Please, be prepared and ready for work.
Be attentive. (No cell phones, video games,snacks or fixing make-up during classes!)
Ask relevant questions!
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
Chemistry is the science concerned with the
composition, structure, and properties of matter, as well as the changes it undergoes during chemical reactions.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
Matter is anything that has mass and volume (occupies space).
Chemistry is the science concerned with the
composition, structure, and properties of matter, as well as the changes it undergoes during chemical reactions.
Matter is basically everything around us, us included.
The amount of matter measured by its resistance to acceleration (movement)
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
Matter is anything that has mass and volume (occupies space).
Chemistry is the science concerned with the
composition, structure, and properties of matter, as well as the changes it undergoes during chemical reactions.
Matter is basically everything around us, us included.
The amount of matter measured by its resistance to acceleration (movement)
Mass is a measurement of matter present.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
Matter is anything that has mass and volume (occupies space).
Chemistry is the science concerned with the
composition, structure, and properties of matter, as well as the changes it undergoes during chemical reactions.
Matter is basically everything around us, us included.
The amount of matter measured by its resistance to acceleration (movement)
Mass is a measurement of matter present.
Weight is a measurement of the gravitational force acting on an object.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
Characteristics of objects: shape, size, color…
(scientific terms): PROPERTIES OF MATTER
Physical properties can be observed or measured without changing the composition of matter.
Physical properties are used to observe and describe matter.
Physical properties include: appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many others.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
Chemical property is any of a material's properties that becomes evident during a chemical reaction.
Chemical property is any quality that can be established only by changing a substance's composition.
Simply speaking, chemical properties cannot be determined just by viewing or touching the substance.
The substance's internal structure must be affected for its chemical properties to be investigated.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
Physical properties :
NO CHANGE in the composition of matter.
Chemical properties :
CHANGE in the composition of matter.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
SCIENTIFIC METHOD
Scientific method refers to bodies of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge.
To be termed scientific, a method of inquiry must be based on gathering observable,
empirical and measurable evidence subject to specific principles of reasoning. A scientific method consists of the collection of data through observation and experimentation, and the formulation and testing of hypotheses.
The essential elements of a scientific method are:
Characterizations (observations, definitions, and measurements of the subject of inquiry)
Hypotheses (theoretical, hypothetical explanations of observations and measurements of the subject)
Predictions (reasoning including logical deduction from the hypothesis or theory)
Experiments (tests of all of the above)
•Gather information and resources (observe)•Form hypothesis•Perform experiment and collect data•Analyze data•Interpret data and draw conclusions that serve as a starting point for new hypothesis•Publish results•Retest (frequently done by other scientists)
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS
MEASUREMENTis a process to attach a numericalvalue to an observation. This is done to be able to compare or order two or more such observations.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS
MEASUREMENT UNITNUMBER +
(hr, oz, oF, ft, gal, $)(3, 16, 8.9)
MEASUREMENTis a process to attach a numericalvalue to an observation. This is done to be able to compare or order two or more such observations.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS
MEASUREMENT UNITNUMBER +
(hr, oz, oF, ft, gal, $)(3, 16, 8.9)
MEASUREMENTis a process to attach a numericalvalue to an observation. This is done to be able to compare or order two or more such observations.
Units of Measurement provide standards to compare against.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS
The METRIC SYSTEM
Internationally adopted in 1960.
The METRIC SYSTEM is a DECIMAL system
length METERmass KILOGRAMvolume LITRE
Imperial Units
length FOOT, YARD, MILEmass OUNCE, POUNDvolume FLUID OUNCE, GALLON
(US units of measurement)
The fluid ounce in Britain is smaller than the fluid ounce in the US, but the US gallon is smaller than the British gallon
1 foot = 12 inches 1 yard = 3 feet (plural of foot) = 36 inches 1 mile = 1760 yards = 5280 feet
1 meter = 1000 millimeters 1 kilometer = 1000 meters
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS
The SI decimal prefixesOwing to the wide range of values that quantities can have, it has long been the practice to employ prefixes such as milli and mega to indicate decimal
fractions and multiples of metric units. As part of the SI standard, this system has been extended and formalized.
prefix abbreviation multiplier -- prefix abbreviation Multiplier
exa E 1018 deci d 10–1
peta P 1015 centi c 10–2
tera T 1012 milli m 10–3
giga G 109 micro μ 10–6
mega M 106 nano n 10–9
kilo k 103 pico p 10–12
hecto h 102 femto f 10–15
deca da 10 atto a 10–18
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS
Units of measurement provide standards to compare against.
Basic unit of measurementis a specific unit from which other units for the same quantity are obtained by multiplication or division.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS
Units of measurement provide standards to compare against.
Basic unit of measurementis a specific unit from which other units for the same quantity are obtained by multiplication or division.
Derived unit of measurementis a unit obtained by multiplication or division of oneor more basic units.
e.g. area = (length)(length) = (length)2 volume = (length)(length)(length) = (length)3
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS
Conversion Factors for Units of Length1 inch = 2.54 centimeters1 foot = 0.305 meter1 yard = 0.914 meter1 mile = 1.609 kilometers1 nautical mile = 1.852 kilometers1 centimeter = 0.39 inch1 meter = 39.37 inches = 3.28 feet = 1.094 yards1 kilometer = 0.62 miles Conversion Factors for Units of Volume
1 cubic inch = 16.4 cubic centimeters1 cubic foot = 0.0283 cubic meter1 cubic yard = 0.765 cubic meter1 fluid ounce = 29.6 milliliters1 U.S. pint = 0.473 liter1 U.S. quart = 0.946 liter1 U.S. gallon = 3.8 liters1 cubic centimeter = 0.06 cubic inch1 cubic meter = 1.3 cubic yards1 milliliter = 0.034 fluid ounce1 liter = 1.06 U.S. quarts
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS
Conversion Factors for Units of Weight or Mass
1 grain = 64 milligrams1 ounce = 28.35 grams1 pound = 0.45 kilogram 1 gram = 0.035 ounce 1 kilogram = 2.205 pounds 1 metric ton = 1.1 short ton
Standard1 lb = 0.45359237 kg1 kg = 2.204622621849 lb 1 kg = 35.27396194958 oz
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS
Celsius
Fahrenheit
Kelvin
Temperature Conversion
°C = (100/180) X (°F - 32)°F = (1.8 X °C) + 32°K = °C + 273.15°C = °K - 273.15°K = [(100/180) X (°F - 32)] + 273.15°F = [1.8 X (°K - 273.15)] + 32
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS/ENERGY
Energy Units Conversions
British Thermal Unit
Foot-pounds
Joules caloriesKilo-
caloriesKilowatt-
hours
1 British Thermal Unit 1 777.9 1055 252.0 0.252 2.93x10-4
1 Foot-pound 0.001285 1 1.356 0.3238 3.238x10-4 3.766x10-7
1 joule 9.481x10-4 0.7376 1 0.2388 2.388x10-4 2.778x10-7
1 calorie 0.003969 3.088 4.187 1 0.001 1.163x10-6
1 kilocalorie 3.969 3088 4187 1000 1 0.001163
1 kilowatt hour 3413 2.655x106 3.6x106 8.598x105 859.8 1
energy (from the Greek ἐνέργεια - energeia "activity, operation", from ἐνεργός - energos, "active, working") is a scalar physical quantity that describes the amount of work that can be performed by a force.
Energy is an attribute of objects and systems that is subject to a conservation law. Several different forms of energy exist to explain all known natural phenomena. These forms include (but are not limited to) kinetic, potential, thermal, gravitational, sound, light, elastic, and electromagnetic energy. The forms of energy are often named after a related force. Any form of energy can be transformed into another form, but the total energy always remains the same.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
ENERGYThe forms of energy are kinetic, potential, thermal, gravitational, sound, light, elastic, and electromagnetic energy. KINETIC ENERGY
The energy a particle has asA result of its motion.
1KE = ----- mv2
2
POTENTIAL ENERGY
The energy a particle has asA result of attractive or repulsive forces acting on it.
COHESIVE FORCE
The attractive force between particles; it is associated with potential energy.
DISRUPTIVE FORCE
The force resulting from particles motion; it is associated with kinetic energy.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS
Temperature Conversion
°C = (100/180) X (°F - 32)°F = (1.8 X °C) + 32°K = °C + 273.15°C = °K - 273.15°K = [(100/180) X (°F - 32)] + 273.15°F = [1.8 X (°K - 273.15)] + 32
Conversion Factors for Units of Weight or Mass
1 grain = 64 milligrams1 ounce = 28.35 grams1 pound = 0.45 kilogram 1 gram = 0.035 ounce 1 kilogram = 2.205 pounds 1 metric ton = 1.1 short ton
Standard1 lb = 0.45359237 kg1 kg = 2.204622621849 lb 1 kg = 35.27396194958 oz
Conversion Factors for Units of Volume
1 cubic inch = 16.4 cubic centimeters1 cubic foot = 0.0283 cubic meter1 cubic yard = 0.765 cubic meter1 fluid ounce = 29.6 milliliters1 U.S. pint = 0.473 liter1 U.S. quart = 0.946 liter1 U.S. gallon = 3.8 liters1 cubic centimeter = 0.06 cubic inch1 cubic meter = 1.3 cubic yards1 milliliter = 0.034 fluid ounce1 liter = 1.06 U.S.quarts
Conversion Factors for Units of Length
1 inch = 2.54 centimeters1 foot = 0.305 meter1 yard = 0.914 meter1 mile = 1.609 kilometers1 nautical mile = 1.852 kilometers1 centimeter = 0.39 inch1 meter = 39.37 inches = 3.28 feet = 1.094 yards1 kilometer = 0.62 miles
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS
High accuracy, but low precision
High precision, but low accuracy
ACCURACY is a MEASURE of the degree of agreement between a MEASURED value and TRUE value of the dimension measured.
PRECISION is a MEASURE of the degree of agreement between a SUCCESSIVE MEASUREMENTS of the SAME property of the SAME item.
All measurements are subject to two kinds of errors:
1. ERRORS due to the measuring instrument
2. ERRORS due to the person doing the measuring
El Camino College Chemistry 21A Dr. Dragan Marinkovic
CALCULATING PERCENTAGES
What is a percentage?
Percent means “for every 100” or "out of 100." The (%) symbol as a quick way to write a fraction with a denominator of 100. As an example, instead of saying "it rained 14 days out of every 100," we say "it rained 14% of the time."
12 people out of a total of 25 were female. What percentage were female?
The price of a $1:50 candy bar was to be increased by 20%. What was the new price?
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MEASUREMENTS
The PERCENTAGE ERROR tells the degree of accuracy of your work, the agreement between your value and accepted value of the measurement.
(accepted value) – (experimental value)% error = --------------------------------------------------------- x 100
accepted value
(actual value) – (estimated value)% error = --------------------------------------------------------- x 100
actual value
El Camino College Chemistry 21A Dr. Dragan Marinkovic
LARGE AND SMALL NUMBERSScientific notation is simply a method for expressing, and working with, very large or very small numbers.
5.67 x 105
This is the scientific notation for the standard number, 567 000. Now look at the number again, with the three parts labeled.
5.67 x 105 coefficient base exponent
1. The coefficient must be greater than or equal to 1 and less than 10.2. The base must be 10.3. The exponent must show the number of decimal places that the decimal needs to be moved to change the number to standard notation. A negative exponent means that the decimal is moved to the left when changing to standard notation.
Changing numbers from scientific notation to standard notation. Ex.1 Change 6.03 x 107 to standard notation.
remember, 107 = 10 x 10 x 10 x 10 x 10 x 10 x 10 = 10 000 000 so, 6.03 x 107 = 6.03 x 10 000 000 = 60 300 000
answer = 60 300 000Instead of finding the value of the base, we can simply move the decimal seven places to the right
because the exponent is 7.So, 6.03 x 107 = 60 300 000
Now let us try one with a negative exponent.Ex.2 Change 5.3 x 10-4 to standard notation.
The exponent tells us to move the decimal four places to the left.so, 5.3 x 10-4 = 0.00053
El Camino College Chemistry 21A Dr. Dragan Marinkovic
LARGE AND SMALL NUMBERS
Rule for Multiplication - When you multiply numbers with scientific notation, multiply the coefficients together and add the exponents. The base will remain 10.
Ex 1. Multiply (3.45 x 107) x (6.25 x 105)first rewrite the problem as: (3.45 x 6.25) x (107 x 105)
Then multiply the coefficients and add the exponents: 21.5625 x 1012
Then change to correct scientific notation: 2.16 x 1013
NOTE - we add one to the exponent because we moved the decimal one place to the left.
Rule for Division - When dividing with scientific notation, divide the coefficients and subtract the exponents. The base will remain 10.
Ex. 1 Divide 3.5 x 108 by 6.6 x 104 rewrite the problem as: 3.5 x 108
--------- 6.6 x 104
Divide the coefficients and subtract the exponents to get: 0.530303 x 104 Change to correct scientific notation to get: 5.30303 x 103
Note - We subtract one from the exponent because we moved the decimal one place to the right.
Rule for Addition and Subtraction - when adding or subtracting in scientific notation, you must express the numbers as the same power of 10. This will often involve changing the decimal place of the coefficient.
Ex. 1 Add 3.76 x 104 and 5.5 x 102 move the decimal to change 5.5 x 102 to 0.055 x 104
add the coefficients and leave the base and exponent the same: 3.76 + 0.055 = 3.815 x 104
El Camino College Chemistry 21A Dr. Dragan Marinkovic
SIGNIFICANT FIGURES
"The population of our city is 157,872.""The number of registered voters as of Jan 1 was 27,833."
= RELIABLE FIGURES
El Camino College Chemistry 21A Dr. Dragan Marinkovic
SIGNIFICANT FIGURES
"The population of our city is 157,872.""The number of registered voters as of Jan 1 was 27,833."
The first statement cannot possibly be correct. Even if a city’s population could be defined in a precise way (Permanent residents? Warm bodies?), how can we account for the minute-by minute changes that occur as people are born and die, or move in and move away?
= RELIABLE FIGURES
El Camino College Chemistry 21A Dr. Dragan Marinkovic
SIGNIFICANT FIGURES
"The population of our city is 157,872.""The number of registered voters as of Jan 1 was 27,833."
The first statement cannot possibly be correct. Even if a city’s population could be defined in a precise way (Permanent residents? Warm bodies?), how can we account for the minute-by minute changes that occur as people are born and die, or move in and move away?
Making sure that numbers make sense
157900 (the significant digits are underlined here) implies that the population is believed to be within the range of about 157850 to about 157950. In other words, the population is 157900±50. The “plus-or-minus 50” appended to this number means that we consider the absolute uncertainty of the
population measurement to be 50 – (–50) = 100. We can also say that the relative uncertainty is 100/157900, which we can also express as 1 part in 1579, or 1/1579 = 0.000633, or about 0.06 percent.
The value 158000 implies that the population is likely between about 157500 and 158500, or 158000±500. The absolute uncertainty of 1000 translates into a relative uncertainty of 1000/158000 or 1
part in 158, or about 0.6 percent.
= RELIABLE FIGURES
El Camino College Chemistry 21A Dr. Dragan Marinkovic
SIGNIFICANT FIGURES
A significant digit is all the numerals in a measured quantity (counting from the left) whose values are considered as known exactly, plus one more whose value could be one more or one less.
The concept of significant digits has less to do with mathematics than with our confidence in a measurement.
Rounding off always leads to the loss of numeric information, what we are getting rid of can be considered to be “numeric noise” that does not contribute to the quality of the measurement.
The purpose in rounding off is to avoid expressing a value to a greater degree of precision than is consistent with the uncertainty in the measurement.
= RELIABLE FIGURES
El Camino College Chemistry 21A Dr. Dragan Marinkovic
SIGNIFICANT FIGURES
The concept of significant digits has less to do with
mathematics than with our confidence in a measurement.
It is "six point something": more than six but less than seven. With certainty we can say it is in the range of 6 to 7. Exactly where in that range is a estimate. We might guess it is 40% of the way, just less than halfway, between 6 and 7 or 6.4.
If we had more marks on the scale we could make a better guess.
It is clear that our estimate was close, but the measurement still does not align with a mark. Not only that, but we are having trouble reading the marks now because they are so fine. Now we can estimate with a higher precision that the measurement is 6.39, although you might say that it is 6.38 or even 6.40. Whatever it is, your best guess is 'correct' although it is not certain.Note the distinction between 6.4, 6.40, and 6.400. The three numbers indicate that the measurements were made with three different instruments. If you don't understand why they are different carefully readthe section on significant figures below.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
SIGNIFICANT FIGURES
The rules for rounding off
If the first non-significant digit is less than 5, then the least significant digit remains unchanged. If the first non-significant digit is greater than 5, the least significant digit is incremented by 1. If the first non-significant digit is 5, the least significant digit can either be incremented or left unchanged, All non-significant digits are removed.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
SIGNIFICANT FIGURES
The rules for rounding off
If the first non-significant digit is less than 5, then the least significant digit remains unchanged. If the first non-significant digit is greater than 5, the least significant digit is incremented by 1. If the first non-significant digit is 5, the least significant digit can either be incremented or left unchanged, All non-significant digits are removed.
number to round /no. of sig. digits result comment
34.216 / 3 34.2 First non-significant digit (1) is less than 5, so number is simply truncated.
2.252 / 2 2.2 or 2.3
First non-significant digit is 5, so least sig. digit can either remain unchanged or be incremented.
39.99 / 3 40.0 Crossing "decimal boundary", so all numbers change.
85,381 / 3 85,400 The two zeros are just placeholders
0.04597 / 3 0.0460 The two leading zeros are not significant digits.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
SIGNIFICANT FIGURES
EXACT NUMBERS have no uncertainty
NUMBERS from defined relationships counting NUMBERS
NUMBERS that are part of reduced simple fractions (1/3, 5/9)
1 foot = 12 inches
There are 100 years in a century.
= RELIABLE FIGURES
El Camino College Chemistry 21A Dr. Dragan Marinkovic
USING UNITS IN CALCULATIONS
FACTOR-UNIT METHOD a systematical approach
(a.k.a. FACTOR-LABEL METHOD to solving numerical
or DIMENSIONAL ANALYSIS) problems.
How many inches in 3.0 feet ?
(given)(conversion) = answer
or Let's take 2.56 quarts and find out how many liters it is.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
USING UNITS IN CALCULATIONS
Which of the following is the longest length?
3.005 x 103 decimeters
1.522 x 10-3 megameters
6.563 x 104 inches
3.122 x 108 micrometers
3.242 x 102 feet
El Camino College Chemistry 21A Dr. Dragan Marinkovic
USING UNITS IN CALCULATIONS
Which of the following is the longest length?
3.005 x 103 decimeters
1.522 x 10-3 megameters
6.563 x 104 inches
3.122 x 108 micrometers
3.242 x 102 feet
El Camino College Chemistry 21A Dr. Dragan Marinkovic
USING UNITS IN CALCULATIONS
Which of the following is the longest length?
3.005 x 103 decimeters
1.522 x 10-3 megameters
6.563 x 104 inches
3.122 x 108 micrometers
3.242 x 102 feet
El Camino College Chemistry 21A Dr. Dragan Marinkovic
USING UNITS IN CALCULATIONS
Which of the following is the longest length?
3.005 x 103 decimeters
1.522 x 10-3 megameters
6.563 x 104 inches
3.122 x 108 micrometers
3.242 x 102 feet
El Camino College Chemistry 21A Dr. Dragan Marinkovic
USING UNITS IN CALCULATIONS
Which of the following is the longest length?
3.005 x 103 decimeters
1.522 x 10-3 megameters
6.563 x 104 inches
3.122 x 108 micrometers
3.242 x 102 feet
El Camino College Chemistry 21A Dr. Dragan Marinkovic
USING UNITS IN CALCULATIONS
Which of the following is the longest length?
3.005 x 103 decimeters
1.522 x 10-3 megameters
6.563 x 104 inches
3.122 x 108 micrometers
3.242 x 102 feet
El Camino College Chemistry 21A Dr. Dragan Marinkovic
USING UNITS IN CALCULATIONS
Which of the following is the longest length?
3.005 x 103 decimeters
1.522 x 10-3 megameters
6.563 x 104 inches
3.122 x 108 micrometers
3.242 x 102 feet
El Camino College Chemistry 21A Dr. Dragan Marinkovic
USING UNITS IN CALCULATIONS
Temperature Conversion
°C = (100/180) X (°F - 32)°F = (1.8 X °C) + 32°K = °C + 273.15°C = °K - 273.15°K = [(100/180) X (°F - 32)] + 273.15°F = [1.8 X (°K - 273.15)] + 32
Conversion Factors for Units of Weight or Mass
1 grain = 64 milligrams1 ounce = 28.35 grams1 pound = 0.45 kilogram 1 gram = 0.035 ounce 1 kilogram = 2.205 pounds 1 metric ton = 1.1 short ton
Standard1 lb = 0.45359237 kg1 kg = 2.204622621849 lb 1 kg = 35.27396194958 oz
Conversion Factors for Units of Volume
1 cubic inch = 16.4 cubic centimeters1 cubic foot = 0.0283 cubic meter1 cubic yard = 0.765 cubic meter1 fluid ounce = 29.6 milliliters1 U.S. pint = 0.473 liter1 U.S. quart = 0.946 liter1 U.S. gallon = 3.8 liters1 cubic centimeter = 0.06 cubic inch1 cubic meter = 1.3 cubic yards1 milliliter = 0.034 fluid ounce1 liter = 1.06 U.S.quarts
Conversion Factors for Units of Length
1 inch = 2.54 centimeters1 foot = 0.305 meter1 yard = 0.914 meter1 mile = 1.609 kilometers1 nautical mile = 1.852 kilometers1 centimeter = 0.39 inch1 meter = 39.37 inches = 3.28 feet = 1.094 yards1 kilometer = 0.62 miles
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
Matter exists in three distinct physical states:
GAS
LIQUID and
SOLID
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
Gases take the shape of a container and fully fill the (closed) container – i.e. have the same
volume as the inside of the container.
Solids retain the shape regardless of the size or shape of the container they are in.
Liquids take the shape of a container, but retain their volume.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
Scientific models are explanation of observed behaviour.
A MODEL OF MATTER
All matter is made up of particles that are too small to see. These particles are named MOLECULES.
MOLECULES are the smallest particle of pure substance that has properties of that substance and is capable of stable independent existence.
MOLECULE is the limit of physical subdivision for a pure substance.Any further separation has to be done chemically creating new entities that would not have the properties of the larger sample.
The smaller particles that make up MOLECULES are called ATOMS.
Basic concepts of MODEL OF MATTER:
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
A MODEL OF MATTER
3. Compounds consisted of atoms of different elements combined together.
4. Compounds have constant composition because they contain a
fixed ratio of atoms and each atom has its own characteristic weight, thus fixing the weight ratio of one element to the other.
5. Chemical reactions involve the rearrangement, separation or combinations of atoms, but the atoms are never created or destroyed
John Dalton developed first ATOMIC THEORY (1808).
1. Elements (and all matter) consist of tiny particles called atoms. 2. All atoms of an element are identical and they have the same mass.
The reason elements differ from one another is that atoms of each
element are different from one another; in particular, they have different masses.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
A MODEL OF MATTER
John Dalton developed first ATOMIC THEORY (1808).
Various atoms and molecules as depicted in John Dalton's A New System of Chemical Philosophy (1808).
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
A MODEL OF MATTER
carbon dioxide
nitrogen carbon monoxide
ammonia
diatomic molecules
homoatomic
heteroatomic
triatomic
polyatomic
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
water, sugar, table salt, carbohydrates, electrolytes (110 mg sodium, 30 mg potassium, 93 mg chloride), high fructose corn syrup, artificial colors, glucose, fructose
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
PURE SUBSTANCEMatter that has
constant composition and fixed properties
ELEMENTS
COMPOUNDS
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
MIXTUREPhysical blend of matter
that technically can bephysically separated into two or more components
HOMOGENEOUS MATTERMatter that has the
same properties throughout the sample
HETEROGENEOUS MATTERMatter with propertiesthat are not the samethroughout the sample
El Camino College Chemistry 21A Dr. Dragan Marinkovic
MATTER
MIXTUREPhysical blend of matter
that technically can bePhysically separated into two or more components
HOMOGENEOUS MATTERMatter that has the
same properties throughout the sample
SOLUTION
Homogeneous mixture of two or more pure substances
El Camino College Chemistry 21A Dr. Dragan Marinkovic
DENSITY
Each box has the same volume. If each ball has the same mass, which box would weigh more? Why?
El Camino College Chemistry 21A Dr. Dragan Marinkovic
DENSITY
Each box has the same volume. If each ball has the same mass, which box would weigh more? Why?
The box that has more balls has more mass per unit of volume. This property of matter is called density.
The density of a material helps to distinguish it from other materials.
El Camino College Chemistry 21A Dr. Dragan Marinkovic
DENSITY
Each box has the same volume. If each ball has the same mass, which box would weigh more? Why?
The box that has more balls has more mass per unit of volume. This property of matter is called density.
The density of a material helps to distinguish it from other materials.
mass mdensity ------------ = ------ = d
volume V
High density: iron, lead, gold
Low density: styrofoam, fat, wood
Material Density(gm/cm3)
Water at 4oC 1.0000Water at 20oC 0.998Ice at 0oC 0.92Gasoline 0.70Mercury 13.6Milk 1.03Magnesium 1.7Aluminum 2.7Copper 8.3-9.0Gold 19.3Air 0.001293Carbon dioxide 0.001977Carbon monoxide 0.00125Hydrogen 0.00009Helium 0.000178Nitrogen 0.001251
El Camino College Chemistry 21A Dr. Dragan Marinkovic
DENSITY
mass mdensity ------------ = ------ = d
volume VSpecific gravity is defined as the ratio of the density of a given solid or liquid substance to the density of water at a specific temperature and pressure, typically at 4°C (39°F) and 1 atm (760.00 mmHg) , making it a dimensionless quantity.
dsubstance
SG = ---------- dwater
Balsa wood has a specific gravity of 0.2, so it is 0.2 times as dense as water. Aluminum has a specific gravity of 2.7, so it is 2.7 times as dense as water. Lead has a specific gravity of 11.35, so it is 11.35 times as dense as water. Mercury has a specific gravity of 13.56, so it is 13.56 times as dense as water.