Better Safe than Sorry
By Anne Marie Helmenstine, Ph.D., About.com
Some rules are NOT made to be broken. That is true of the rules used in a chemistry lab. They are really, truly for your safety and not your humiliation.
• Do Not Pipette By Mouth - Ever
You say, "But it's only water." Even if it is, how clean do you think that glassware really is? Using disposable pipettes? I know lots of people who rinse them and put them back! Learn to use the pipette bulb or automated pipetter. Don't pipette by mouth at home either. Gasoline and kerosene should be obvious, but people get hospitalized or die every year, right? I know someone who used his mouth to start the suction on a waterbed to drain it. Do you know what they put in some waterbed additives? Carbon-14. Mmmm...radiation. He couldn't retch fast enough! The lesson is that even seemingly harmless substances may be dangerous!
• Read the Chemical Safety Information
A Material Safety Data Sheet (MSDS) should be available for every chemical you use in lab. Read these and follow the recommendations for safe use and disposal of the material.
• Dress Appropriately (for chemistry lab, not fashion or the weather)
No sandals, no clothes you love more than life, no contact lenses, and long pants are preferable to shorts or short skirts. Tie long hair back. Wear safety goggles and a lab coat. Even if you aren't clumsy, someone else in the lab probably is. If you take even a few chemistry courses you will probably see people set themselves on fire, spill acid on themselves, others, or notes, splash themselves in the eye, etc. Don't be the bad example to others, remembered for all time for something stupid!
• Identify the Safety Equipment
And know how to use it! Given that some people (possibly you) will need them, know the locations of the fire blanket, extinguishers, eyewash, and shower. Ask for demonstrations! If the eyewash hasn't been used in a while the discoloration of the water is usually sufficient to inspire use of safety glasses.
• Don't Taste or Sniff Chemicals
For many chemicals, if you can smell them then you are exposing yourself to a dose that can harm you! If the safety information says that a chemical should only be used inside a fume hood, then don't use it anywhere else. This isn't cooking class - don't taste your experiments!
• Don't Casually Dispose of Chemicals Down the Drain
Some chemicals can be washed down the drain, while others require a different method of disposal. If a chemical can go in the sink, be sure to wash it away rather than risk an unexpected reaction between chemical 'leftovers' later.
• Don't Eat or Drink in Lab
It's tempting, but oh so dangerous... just don't do it!
• Don't Play Mad Scientist
Don't haphazardly mix chemicals! Pay attention to the order in which chemicals are to be added to each other and do not deviate from the instructions. Even chemicals that mix to produce seemingly safe products should be handled carefully. For example, hydrochloric acid and sodium hydroxide will give you salt water, but the reaction could break your glassware or splash the reactants onto you if you aren't careful!
• Take Data During Lab
Not after lab, on the assumption that it will be neater. Put data directly in your lab book rather than transcribing from another source (e.g., notebook or lab partner). There are lots of reasons for this, but the practical one is that it is much harder for the data to get lost in your lab book. For some experiments, it may be helpful to take data beforelab. No, I'm not telling you to dry-lab or cheat, but being able to project likely data will help you catch bad lab procedure before you are three hours or so into a project. Know what to expect. You should always read the experiment in advance.
Rabu, 20 Agustus 2008
Chemistry - The Central Science
In modern thought, Chemistry (from Egyptian ? Chem or Keme meaning ?earth? or ?black?, due to the rich soil) is connected to almost all other natural sciences: astronomy, biology, geology, material science, physics, etc. The subcategories of chemistry are getting more specialized as time passes and the understanding of the composition and structure of matter increases.
Some of the basic subdisciplines of matter studied include (but are not limited to): analytical chemistry, biochemistry, inorganic chemistry, nuclear chemistry, organic chemistry, physical chemistry, and theoretical chemistry.
Alchemy most often refers to both the early form of investigation of nature and philosophy that combine elements of many disciplines. Having been studied everywhere from Ancient Mesopotamia and Egypt to Classical Greece and Rome as well as the orient and the Mediterranean for well over 2 millennia, its diversity may be as great as science itself.
In history, Alchemy (from Arabic ? al-chimiya ? likely similar root word from Egyptian) was more than simply connected to many disciplines; it was composed of them: art, astrology, chemistry, medicine, metallurgy, mysticism, physics, semiotics, spiritualism, etc.
The Greek philosopher Empedocles championed the idea that all things were composed of four basic elements: Earth, Air, Fire, and Water. The four elements were attributed properties: cold, dry, hot, and wet. The interaction of these four elements can be demonstrated by the following relationship order: Water ? wet ? Air ? hot ? Fire ? dry ? Earth ? cold ? Water (ad nauseum). Around 350 BCE, Aristotle conceived of a fifth element that he called ?quintessence? which made up the heavens.
Initially an ?Element? was defined as a body in which other bodies can be decomposed and which itself is not capable of being divided into other bodies. This definition is nearly identical to the concept of the atom as the indivisible component of matter.
Nasir al-Din al-Tusi (1201-1274) suggested in his writings from the 13th century that a body of matter is able to change, but is not able to simply disappear. While his theory was incomplete, it is likely to have inspired those conservationists of the 5 centuries that came after him until the Law of Conservation of Mass was fully formulated in 1789 by Antoine Lavoisier (the father of modern chemistry).
When the scientific community figured out that the substances never disappear, then they were finally able to embark on thorough studies on the transformation of substances.
Following the chemical revolution, the physical science of chemistry began to relate to smaller and smaller parts. Then, of course, physicists discovered subatomic particles and decided that atoms were not indivisible. The atom consists of electrons (British physicist Sir Joseph John ?J.J.? Thomson, 1897), protons (the ?father? of nuclear physics, Lord Ernest Rutherford, 1918), and for most atoms, the neutron (physicist Sir James Chadwick, 1932).
In time, it was discovered that both protons and neutrons are composed of ?elementary particles? called quarks (Murray Gell-Mann, 1961). Quarks are a type of fermion (Enrico Fermi + suffix ?on?) which is one of the two basic constituents of matter. The electron is an example of the other constituent, the lepton (from the Greek leptos meaning ?thin?) (physicist Leon Rosenfeld, 1948).
Quarks, so named as a nonsense word to rhyme with ?pork? and spelled to match a word from Finnegan?s Wake by James Joyce (though it should rhyme with ?Mark?).
Six flavors (or types) of quarks are known to exist: up, down, top, bottom, strange, and charm. These terms were abitrarily coined based on necessity of names which were easy to use and remember. All subatomic particles are composed of 3 of the 6 quarks combined in specific ways. Each quark has a different mass and fractional electric charge. They are held together by the strong nuclear force and mediated by gluons (glue + suffix ?on?).
The discovery of the buoyant effect of our planet?s atmosphere on the weight of gases was of key importance to the transmutation from the Art of Alchemy to the Science of Chemistry. This allowed for quantitative studies on the transformation of substances thus in turn leading to the idea that chemical processes themselves are simply reactions between chemical elements of different amounts.
Some of the basic subdisciplines of matter studied include (but are not limited to): analytical chemistry, biochemistry, inorganic chemistry, nuclear chemistry, organic chemistry, physical chemistry, and theoretical chemistry.
Alchemy most often refers to both the early form of investigation of nature and philosophy that combine elements of many disciplines. Having been studied everywhere from Ancient Mesopotamia and Egypt to Classical Greece and Rome as well as the orient and the Mediterranean for well over 2 millennia, its diversity may be as great as science itself.
In history, Alchemy (from Arabic ? al-chimiya ? likely similar root word from Egyptian) was more than simply connected to many disciplines; it was composed of them: art, astrology, chemistry, medicine, metallurgy, mysticism, physics, semiotics, spiritualism, etc.
The Greek philosopher Empedocles championed the idea that all things were composed of four basic elements: Earth, Air, Fire, and Water. The four elements were attributed properties: cold, dry, hot, and wet. The interaction of these four elements can be demonstrated by the following relationship order: Water ? wet ? Air ? hot ? Fire ? dry ? Earth ? cold ? Water (ad nauseum). Around 350 BCE, Aristotle conceived of a fifth element that he called ?quintessence? which made up the heavens.
Initially an ?Element? was defined as a body in which other bodies can be decomposed and which itself is not capable of being divided into other bodies. This definition is nearly identical to the concept of the atom as the indivisible component of matter.
Nasir al-Din al-Tusi (1201-1274) suggested in his writings from the 13th century that a body of matter is able to change, but is not able to simply disappear. While his theory was incomplete, it is likely to have inspired those conservationists of the 5 centuries that came after him until the Law of Conservation of Mass was fully formulated in 1789 by Antoine Lavoisier (the father of modern chemistry).
When the scientific community figured out that the substances never disappear, then they were finally able to embark on thorough studies on the transformation of substances.
Following the chemical revolution, the physical science of chemistry began to relate to smaller and smaller parts. Then, of course, physicists discovered subatomic particles and decided that atoms were not indivisible. The atom consists of electrons (British physicist Sir Joseph John ?J.J.? Thomson, 1897), protons (the ?father? of nuclear physics, Lord Ernest Rutherford, 1918), and for most atoms, the neutron (physicist Sir James Chadwick, 1932).
In time, it was discovered that both protons and neutrons are composed of ?elementary particles? called quarks (Murray Gell-Mann, 1961). Quarks are a type of fermion (Enrico Fermi + suffix ?on?) which is one of the two basic constituents of matter. The electron is an example of the other constituent, the lepton (from the Greek leptos meaning ?thin?) (physicist Leon Rosenfeld, 1948).
Quarks, so named as a nonsense word to rhyme with ?pork? and spelled to match a word from Finnegan?s Wake by James Joyce (though it should rhyme with ?Mark?).
Six flavors (or types) of quarks are known to exist: up, down, top, bottom, strange, and charm. These terms were abitrarily coined based on necessity of names which were easy to use and remember. All subatomic particles are composed of 3 of the 6 quarks combined in specific ways. Each quark has a different mass and fractional electric charge. They are held together by the strong nuclear force and mediated by gluons (glue + suffix ?on?).
The discovery of the buoyant effect of our planet?s atmosphere on the weight of gases was of key importance to the transmutation from the Art of Alchemy to the Science of Chemistry. This allowed for quantitative studies on the transformation of substances thus in turn leading to the idea that chemical processes themselves are simply reactions between chemical elements of different amounts.
Selasa, 19 Agustus 2008
Chemistry - How To Survive Your Chemistry Class
By Darrell Causey, ezinearticles.com
After years of teaching, I have discovered that success in any chemistry class has nothing to do with special abilities, superior intelligence, or high SAT scores. Success in chemistry is directly related to your attitude, your willingness to prepare and your persistence.
It doesn't matter what your skills are if you have a lousy attitude, refuse to do your assignments and won't make time to practice, you will not succeed. You must have a positive outlook towards chemistry, be willing to do the work, and practice, practice, practice. But, if you can do the three things mentioned above then you will be successful in chemistry.
Attitude
Your attitude toward chemistry is completely under your control. No one can make you think anything you don't want to think. So, the first thing you need to do is get control of your thoughts.
If you say, "chemistry is hard", it will be hard. If you say, "I will never pass chemistry" then you won't pass chemistry.
The mind is very powerful and will function according to how you feed it. If you feed it negative thoughts you will get negative results. You must be aware of your thoughts and if they are negative, change them. No one else can do it for you. Finally, you must not let what other people think about you, determine your reality. Just because someone says you can't do something doesn't mean you have to accept his or her opinion. All that truly matters is what you believe. Don't let other people set your limits or your goals.
Preparation
What's important now produces the acronym WIN and that's exactly what successful people must ask when deciding what to do. In order to be successful you must learn to set priorities and do what's important now. If you choose to do something else, then you chose to fail: not your parents, your teacher or your friends. You!
What's important now? Whatever you need to do to further your goals is what's important now. If you need to learn a particular skill, learn it. If you need to spend more time on a certain project, do it. If you need help, get it. It's up to you to consider your goals and do what's important now.
Practice
If you are serious about doing well in chemistry, you must be willing to practice. Chemistry is a discipline dependent on other disciplines and skills. So, it is important that you practice these skills in order to master chemistry.
These skills are:
• Understanding the scientific method
• Learn the metric system (cgs)
• Learn scientific notation
• Learn the use of significant figures
• Master the secrets of the periodic table
• Develop simple algebra skills
• Basic calculator skills
So, maintain a positive attitude, properly prepare for class and consistently practice the skills listed above and you will be a success in college chemistry.
After years of teaching, I have discovered that success in any chemistry class has nothing to do with special abilities, superior intelligence, or high SAT scores. Success in chemistry is directly related to your attitude, your willingness to prepare and your persistence.
It doesn't matter what your skills are if you have a lousy attitude, refuse to do your assignments and won't make time to practice, you will not succeed. You must have a positive outlook towards chemistry, be willing to do the work, and practice, practice, practice. But, if you can do the three things mentioned above then you will be successful in chemistry.
Attitude
Your attitude toward chemistry is completely under your control. No one can make you think anything you don't want to think. So, the first thing you need to do is get control of your thoughts.
If you say, "chemistry is hard", it will be hard. If you say, "I will never pass chemistry" then you won't pass chemistry.
The mind is very powerful and will function according to how you feed it. If you feed it negative thoughts you will get negative results. You must be aware of your thoughts and if they are negative, change them. No one else can do it for you. Finally, you must not let what other people think about you, determine your reality. Just because someone says you can't do something doesn't mean you have to accept his or her opinion. All that truly matters is what you believe. Don't let other people set your limits or your goals.
Preparation
What's important now produces the acronym WIN and that's exactly what successful people must ask when deciding what to do. In order to be successful you must learn to set priorities and do what's important now. If you choose to do something else, then you chose to fail: not your parents, your teacher or your friends. You!
What's important now? Whatever you need to do to further your goals is what's important now. If you need to learn a particular skill, learn it. If you need to spend more time on a certain project, do it. If you need help, get it. It's up to you to consider your goals and do what's important now.
Practice
If you are serious about doing well in chemistry, you must be willing to practice. Chemistry is a discipline dependent on other disciplines and skills. So, it is important that you practice these skills in order to master chemistry.
These skills are:
• Understanding the scientific method
• Learn the metric system (cgs)
• Learn scientific notation
• Learn the use of significant figures
• Master the secrets of the periodic table
• Develop simple algebra skills
• Basic calculator skills
So, maintain a positive attitude, properly prepare for class and consistently practice the skills listed above and you will be a success in college chemistry.
Top Reasons Why Students Fail Chemistry
By Anne Marie Helmenstine, Ph.D., About.com
Are you taking a chemistry class? Are you worried you might not pass? Chemistry is a subject many students prefer to avoid, even if they have an interest in science, because of its reputation for lowering grade point averages. However, it isn't as bad as it seems, especially if you avoid these common mistakes.
1. Procrastinating
Never do today what you can put off until tomorrow, right? Wrong! The first few days in a chemistry class may be very easy and could lull you into a false sense of security. Don't put off doing homework or studying until halfway through the class. Mastering chemistry requires you to build concept upon concept. If you miss the basics, you'll get yourself into trouble. Pace yourself. Set aside a small segment of time each day for chemistry. It will help you to gain long-term mastery. Don't cram.
2. Insufficient Math Preparation
Don't go into chemistry until you understand the basics of algebra. Geometry helps, too. You will need to be able to perform unit conversions. Expect to work chemistry problems on a daily basis. Don't rely too much on a calculator. Chemistry and physics use math as an essential tool.
3. Not Getting or Reading the Text
Yes, there are classes in which the text is optional or completely useless. This isn't one of those classes. Get the text. Read it! Ditto for any required lab manuals. Even if the lectures are fantastic, you'll need the book for the homework assignments. A study guide may be of limited use, but the basic text is a must-have.
4. Psyching Yourself Out
I think I can, I think I can... you have to have a positive attitude toward chemistry. If you truly believe you will fail you may be setting yourself up for a self-fulfilling prophecy. If you have prepared yourself for the class, you have to believe that you can be successful. Also, it's easier to study a topic you like than one you hate. Don't hate chemistry. Make your peace with it and master it.
5. Not Doing Your Own Work
Study guides and books with worked answers in the back are great, right? Yes, but only if you use them for help and not as an easy way to get your homework done. Don't let a book or classmates do your work for you. They won't be available during the tests, which will count for a big portion of your grade.
Are you taking a chemistry class? Are you worried you might not pass? Chemistry is a subject many students prefer to avoid, even if they have an interest in science, because of its reputation for lowering grade point averages. However, it isn't as bad as it seems, especially if you avoid these common mistakes.
1. Procrastinating
Never do today what you can put off until tomorrow, right? Wrong! The first few days in a chemistry class may be very easy and could lull you into a false sense of security. Don't put off doing homework or studying until halfway through the class. Mastering chemistry requires you to build concept upon concept. If you miss the basics, you'll get yourself into trouble. Pace yourself. Set aside a small segment of time each day for chemistry. It will help you to gain long-term mastery. Don't cram.
2. Insufficient Math Preparation
Don't go into chemistry until you understand the basics of algebra. Geometry helps, too. You will need to be able to perform unit conversions. Expect to work chemistry problems on a daily basis. Don't rely too much on a calculator. Chemistry and physics use math as an essential tool.
3. Not Getting or Reading the Text
Yes, there are classes in which the text is optional or completely useless. This isn't one of those classes. Get the text. Read it! Ditto for any required lab manuals. Even if the lectures are fantastic, you'll need the book for the homework assignments. A study guide may be of limited use, but the basic text is a must-have.
4. Psyching Yourself Out
I think I can, I think I can... you have to have a positive attitude toward chemistry. If you truly believe you will fail you may be setting yourself up for a self-fulfilling prophecy. If you have prepared yourself for the class, you have to believe that you can be successful. Also, it's easier to study a topic you like than one you hate. Don't hate chemistry. Make your peace with it and master it.
5. Not Doing Your Own Work
Study guides and books with worked answers in the back are great, right? Yes, but only if you use them for help and not as an easy way to get your homework done. Don't let a book or classmates do your work for you. They won't be available during the tests, which will count for a big portion of your grade.
Chemistry Study Tips
Chemistry Study Tips
Ideas to Help you Succeed in Chemistry
By Anne Marie Helmenstine, Ph.D., About.com
There is no 'magic formula' for learning chemistry. Basically it involves not getting behind, doing your own work, and not psyching yourself out:
• Don't procrastinate!
Cramming does not equal learning. Yes, yes, I am a hypocrite... the queen of putting-off-until-tomorrow. Take it from someone with experience: if you wait until the night before a test to start studying you will suffer, your grades will suffer, etc.
• Don't Procrastinate
It's worth repeating! In chemistry you build from one concept onto the next. You need a solid knowledge base to progress.
• Try Flash Cards
Hey, they are used in elementary and primary school because FLASHCARDS WORK. Some of the information gets learned while making the cards and the rest can be learned during practice. You get to switch around the order in which you view topics, which is something most notebooks don't provide. Get some index cards and give it a try!
• Try a Highlighter
Use it judiciously. The goal is not to turn your book or notes fluorescent. Most texts already have important concepts in bold typeface. Unless your teacher is very unusual, he or she will almost always mention likely test questions, answers, and concepts. Highlight them! Some teachers take questions from a test bank, but those who write their own are usually keeping a mental tally of concepts while teaching.
• Make Mnemonic Devices
What you are doing here is taking the first letters of words in a sequence you are trying to memorize and making a phrase from them to serve as a memory aid. Example: the sequence of the first few elements in the periodic table H, He, Li, Be, B, C, N, O, F, Ne could be (well, the one that came to my mind was actually dirty, which is easier to remember) Hi Henry, Lookin' Big, Bad, Certainly Nasty, Old Friend - Not! Ok, it isn't great literature. One popular mnemonic device is for metric prefixes: Kilo- Hecto- Deca- Meter (liter, gram) deci- centi- milli- Kangaroos Hopping Down Mountains Drinking Chocolate Milk. Also, such phrases are even easier to memorize if you put them to music.
• Know Your Text
Do you have a glossary? Answers to problems in the back? Self-quizzes? Appendices full of useful information? Find that out sooner rather than later. Use the glossary. You can't communicate about a subject without learning the terminology.
Ideas to Help you Succeed in Chemistry
By Anne Marie Helmenstine, Ph.D., About.com
There is no 'magic formula' for learning chemistry. Basically it involves not getting behind, doing your own work, and not psyching yourself out:
• Don't procrastinate!
Cramming does not equal learning. Yes, yes, I am a hypocrite... the queen of putting-off-until-tomorrow. Take it from someone with experience: if you wait until the night before a test to start studying you will suffer, your grades will suffer, etc.
• Don't Procrastinate
It's worth repeating! In chemistry you build from one concept onto the next. You need a solid knowledge base to progress.
• Try Flash Cards
Hey, they are used in elementary and primary school because FLASHCARDS WORK. Some of the information gets learned while making the cards and the rest can be learned during practice. You get to switch around the order in which you view topics, which is something most notebooks don't provide. Get some index cards and give it a try!
• Try a Highlighter
Use it judiciously. The goal is not to turn your book or notes fluorescent. Most texts already have important concepts in bold typeface. Unless your teacher is very unusual, he or she will almost always mention likely test questions, answers, and concepts. Highlight them! Some teachers take questions from a test bank, but those who write their own are usually keeping a mental tally of concepts while teaching.
• Make Mnemonic Devices
What you are doing here is taking the first letters of words in a sequence you are trying to memorize and making a phrase from them to serve as a memory aid. Example: the sequence of the first few elements in the periodic table H, He, Li, Be, B, C, N, O, F, Ne could be (well, the one that came to my mind was actually dirty, which is easier to remember) Hi Henry, Lookin' Big, Bad, Certainly Nasty, Old Friend - Not! Ok, it isn't great literature. One popular mnemonic device is for metric prefixes: Kilo- Hecto- Deca- Meter (liter, gram) deci- centi- milli- Kangaroos Hopping Down Mountains Drinking Chocolate Milk. Also, such phrases are even easier to memorize if you put them to music.
• Know Your Text
Do you have a glossary? Answers to problems in the back? Self-quizzes? Appendices full of useful information? Find that out sooner rather than later. Use the glossary. You can't communicate about a subject without learning the terminology.
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