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Chemistry FAQs

Find answers to your Frequently Asked Questions (FAQs) about all aspects of chemistry.
  1. Chemistry Forum Questions (8)
  2. Chemistry Site FAQs (22)
  3. Chemistry Student FAQs (124)
  4. Element FAQs (28)
  5. Food Chemistry FAQs (49)
  6. How Things Work FAQs (173)

Chemistry Questions You Should Be Able to Answer
These are questions an educated person should be able to answer relating to chemistry in the everyday world.

What Is the Importance of Chemistry?
What is the importance of chemistry? Why would you want to learn about chemistry? Chemistry is the study of matter and its interactions with other matter and energy. Here's a look at the importance of chemistry and why you should study it.

Can I Teach Myself Chemistry?
You can teach yourself general chemistry with this step-by-step introduction to the basic concepts.

Chemistry Basics - What Is Chemistry
Start learning chemistry with the basics. Learn what chemistry is, what chemists do, and why it's important to study chemistry.

Chemistry Basics - How Do I Study Chemistry?
Here are some homework and study tips to help you succeed in chemistry.

Who Was the First Chemist?
Chemistry has been around for a very long time! Do you know the name of the first chemist in recorded history? Would it surprise you that the first chemist was a woman?

How Do I Make Rock Candy?
Rock candy is candy made by crystallizing sugar. You can grow sugar crystals yourself, plus add color and flavor to make rock candy that you can eat.

Can a Candle Burn in Zero Gravity?
Can a candle burn in the absence of gravity? Here's the answer to this frequently asked question about fire.

Can Hot Water Freeze Faster Than Cold Water?
Can hot water freeze faster than cold water? You may have heard this question and wondered how, if it's true, it could even be possible. Here's the answer to the question.

Can You Drink Too Much Water?
It's important to drink plenty of fluids, but can you overdo it? Learn the truth about water intoxication and hyponatremia.

Can You Use Laundry Detergent in the Dishwasher?
Yes, you could put laundry detergent in your dishwasher. Should you? Probably not. Here's why.

Can Your Hair Turn White from Fright or Turn Gray Overnight?
Is it true your hair can turn white from a bad scare or that your hair can turn gray overnight? Learn about your haircolor and get the answer to the question.

Chemistry Questions and Answers
Is there a chemistry question you think a person with a command of chemistry should be able to answer? Here's your chance to educate or to learn. Pose a chemistry question and answer it or read what others asked… See submissions

Do You Add Sulfuric Acid to Water or Water to Sulfuric Acid?
It's important to add sulfuric acid to water and not water to concentrated sulfuric acid. Here's an explanation of why you don't want to make a mistake and some mnemonics that might help you remember how to play it safe in the chemistry lab.

Do You Burn More Calories when you Think Hard?
Find out how many calories you burn when thinking and how it compares with the energy expended by physical exercise.

Does Bottled Water Go Bad?
Most bottled water has an expiration date stamped on the bottle, but does the bottled water actually go bad? If so, how long is bottled water good? Here's the answer to this common question.

Does Eating Turkey Make You Sleepy?
Find out why everyone wants to take a nap after Thanksgiving Day turkey dinner. Let's talk turkey and learn about L-tryptophan and carbohydrate metabolism.

How Are Elements Named?
Have you ever wondered how the elements are named or why some elements have more than one name? Here's the answer to your question.

How Are New Elements Discovered?
Find out if there are any elements left to be discovered and how they would be found.

How Can I Make a Colored Smoke Bomb?
Make a smoke bomb that billows clouds of brightly colored smoke. This project is easy and safe enough to at home. Adult supervision is required.

How Can I Make a Sparkler?
Learn how to make your own sparklers, for Independence Day or New Years Day fun. Use your understanding of chemistry to color the sparks.

How Can I Make Fake Snow?
You can make fake snow using a common polymer. The fake snow is non-toxic, feels cool and wet to the touch, and looks similar to the real thing.

How Can I Make My Own pH Paper?
You can make pH indicator from poinsettia flowers, then use the indicator to make your own pH paper test strips.

How Can I Reduce my Fluoride Exposure?
Fluoride isn't only found in toothpaste and water. There are many everyday sources and several steps you can take to lower your exposure.

How Can I Test for Vitamin C?
Use this redox-based iodometric titration to determine the amount of Vitamin C or ascorbic acid in juice and other samples.

How Do Blueprints Work?
A blueprint is a paper-based reproduction of a drawing, usually a technical drawing, such as an architect or engineer would use. Learn what blueprints are made from and how they work.

How Do Chemical Weapons Smell?
Do you think chemical weapons smell terrible? You might be surprised to learn many are odorless or smell pleasant.

How Do Detergents Clean?
Learn about the chemistry behind the cleaning power of detergents.

How Do Disposable Diapers Work? Why Do They Leak?
Learn about the polymer in disposable diapers, sodium polyacrylate. Find out how the polymer absorbs water and why diapers leak.

How Do Fireworks Work?
Firecrackers, sparklers, and aerial fireworks are all examples of fireworks. Here's a look at the different types of fireworks and an explanation of how they work.

How Do I Balance Equations?
A chemical equation describes what happens in a chemical reaction. It takes practice to be able to write balanced equations, but the process involves the same basic steps, no matter how complex the reaction. This tutorial guides you through the steps.

How Do I Calculate Concentration?
Do the units for solution concentration confuse you? Get definitions and examples for calculating percent composition by mass, mole fraction, molarity, molality, and normality. I've also included a bit of information on dilutions.

How Do I Clean Laboratory Glassware?
Cleaning laboratory glassware isn't as simple as washing the dishes. Here's how to wash your glassware so that you won't ruin your chemical solution, laboratory experiment, or the glass.

How Do I Dispose of Mercury?
Mercury is an extremely toxic metal that is found in fluorescent light bulbs, mercury thermometers, and other household items. If you break a thermometer or a mercury-containing bulb, it's important to dispose of the mercury properly so that you don't accidentally poison yourself or contaminate the area with mercury.

How Do I Do a Science Fair Project?
Science fair projects are a great way to learn about experimentation, the scientific method, and science concepts. However, it can be hard to find an idea or get answers to questions once you get started. Here is a collection of resources to give your project the winning edge.

How Do I Get the Chemistry Newsletter?
Be sure to sign up for the newsletter to keep up with what is happening in the world of chemistry. In addition to general news, the newsletter highlights the latest additions to this site.

How Do I Grow a Seed Crystal?
A seed crystal is a small single crystal that you use to grow a much larger crystal from a saturated crystal solution. This is how you can grow a seed crystal yourself.

How Do I Join the Chemistry Forum?
If you have homework questions, this is a great place to go to get answers. If you have chemistry knowledge and want to share it with others, this is the place for you, too!

How Do I Make a Mixture? How Do I Make a Compound?
Do you know the difference between a mixture and a compound? Combine iron and sulfur to make a mixture and then react them to form a chemical compound.

How Do I Make and Reveal Invisible Ink?
Make your own invisible ink so you can write and reveal secret messages. Get information about inks that are activated by heat, chemical reactions, and ultraviolet light.

How Do I Make Biodiesel?
As the price of diesel continues to climb, you may wish to consider making your own diesel from cooking oil, called biodiesel. It's easy and could save you money.

How Do I Make Cut Flower Preservative?
It's easy and economical to make your own cut flower preservative. Adding floral preservative will help keep your flowers beautiful much longer than if you simply filled a vase with water.

How Do I Make Disappearing Ink? How Does It Work?
Learn how to make blue or red ink that will disappear after exposure to air. Tips for restoring the color and an explanation of the acid-base chemistry of the reaction are also included.

How Do I Make Floam?
Make your own version of Floam, a type of slime that contains polystyrene beads so that you can mold it into shapes.

How Do I Make Glow in the Dark Slime?
What is better than regular slime? Slime that glows in the dark, of course! This is an easy and fun project that is suitable for kids.

How Do I Make Slime?
Slime is easy and fun to make, plus it only requires glue, borax, and water. Here are step-by-step instructions for making classic slime, complete with photos.

How Do I Memorize the Order of the Elements?
Here's a handy mnemonic device to help memorize the symbols and sequence of the first nine elements in the periodic table.

How Do I Perform the Mohs Test?
The Mohs test is one way to determine the hardness of a rock or mineral. You can use the Mohs hardness to help identify an unknown specimen. Here's how you can do the test yourself.

How Do I Read a Meniscus?
The meniscus is the curve seen at the top of a liquid in response to its container. When you read a scale on the side of a container with a meniscus, such as a graduated cylinder or volumetric flask, it's important that the measurement accounts for the meniscus. Here's how to read a meniscus.

How Do I Subscribe to 'Chemistry Activities for Kids'?
Are you ready for kid-friendly chemistry activities and games? Each newsletter features safe projects, games or quizzes, and links for additional learning. Learn about the elements, grow crystals, and more! When you sign up you'll get one newsletter a week until you've gotten them all.

How Do I Substitute Between Baking Powder and Baking Soda?
Baking powder and baking soda both are leavening agents, which means they help baked goods to rise. They are not the same chemical, but you can substitute one for another in recipes. Here's how.

How Do I Take a Test?
How you take a test is at least as important as your preparation for it. These tips can help you make the grade.

How Do I Unsubscribe from a Newsletter or Change My Address?
It's quick and easy! If you e-mail me asking to change your e-mail address or to be unsubscribed from an About Chemistry newsletter or e-course, these are the instructions I'll give you.

How Do I Use Flash Cards?
Flash cards can be a great study aid. You can use them to help memorize facts, lists, and structures as well as to reinforce important concepts. Here's how to prepare and use flash cards to help study chemistry.

How Do I Write a Bibliography?
Learn how to cite your sources for a science fair project. See examples for books, online references, and conversations.

How Do I Write a Lab Report?
Lab reports are an essential part of all laboratory courses and usually a significant part of your grade. If your instructor gives you an outline for how to write a lab report, use that. Here's a format for a lab report you can use if you aren't sure what to write or need an explanation of what to include in the different parts of the report.

How Do I Write in Scientific Notation?
Scientific notation uses exponents to express numerical figures. Here's an explanation of what scientific notation is, plus examples of how to write numbers and perform addition, subtraction, multiplication and division problems using scientific notation.

How Do Lightsticks Work?
Find out how lightsticks or glowsticks work. Learn about the chemistry behind the process and get on-line purchase information. This article also explains how to make glow sticks last longer or become brighter!

How Do Mood Rings Work?
Mood rings have a stone that is supposed to change color to show your emotions. Do they work? If so, do you know how? Here's your chance to find out.

How Do Pencil Erasers Work?
Learn about the different materials used as pencil erasers and how they work.

How Do Plants Make Food? How Photosynthesis Works
Photosynthesis is the name for the set of chemical reactions used by plants and other organisms to make food from sunlight, carbon dioxide, and water. Here's a look at the process and study questions to help make sure you understand the key concepts.

How Do Pop Rocks Candy Work?
Find out how pop rocks candy works and whether or not it's true your stomach will explode if you wash down pop rocks with soda.

How Do Pregnancy Tests Work?
Learn how blood tests and home pregnancy urine tests work, how early they can be used, and some reasons for false positive and negative test results.

How Do Safety Matches Work?
Learn about how safety matches work and why they are considered 'safe'.

How Do Sunless Tanning Products Work?
This article discusses bronzers, self-tanning lotions and sprays, tanning accelerators, and pills. Learn how these products work and find out why tans fade.

How Do Trick Birthday Candles Work?
You blow them out, but these candles re-light themselves. Magic? No, it's simple chemistry!

How Does Atomic Number Relate to Atomic Mass?
Higher atomic number doesn't imply higher atomic mass. At least not always! Sometimes one element of lower atomic number can have a higher atomic mass. Learn about the effect of isotopic ratios on atomic mass.

How Does Borax Clean?
Borax is used as a multipurpose cleaner and bleach. How does it work? Learn how the chemistry of borax relates to its cleaning power. These same properties are also associated with certain health hazards.

How Does Febreze Remove Odors?
Does Febreze remove odors or merely mask them? Here's a look at how Febreze works, including information about its active ingredient, cyclodextrin, and how the product interacts with odors.

How Does Fluoride Work?
Fluoride is the fluorine ion added to toothpaste and dental rinse to help protect your teeth from cavities. Here's how fluoride works.

How Does Hair Detangler Work?
Learn the chemistry behind how hair detangler works and get recipes to make your own homemade hair detangler.

How Does Jell-O Work?
Jell-O gelatin is a tasty jiggly treat that results from a bit of chemistry kitchen magic. Here's a look at what Jell-O is made from and how Jell-O works.

How Does Popcorn Pop?
Popcorn pops because each popcorn kernel is special. Here's a look at what makes popcorn different from other seeds and how popcorn pops.

How Does Silly Putty Work?
Learn about the history of Silly Putty, how it works, how to make your own, and what you can do to explore the interesting properties of this viscoelastic liquid.

How Does Soap Clean?
You may use it every day, but do you know how it works? Learn about emulsions, micelles, and soap scum! Then check out links to sites about bubbles, soapmaking, and the regulation of soap chemistry.

How Does Sunscreen Work?
Find out how sunscreen works, what an SPF rating means, the difference between sunscreen and sunblock, and how to protect yourself from both UV-A and UV-B radiation.

How Does the Fortune Teller Miracle Fish Work?
If you place the plastic Fortune Teller Miracle Fish in your hand it will bend and wiggle. You can decipher the movements of the fish to predict your future. The movements of the fish are a result of the chemical composition of the fish.

How Is the Water-into-Wine Demonstration Done?
Turn a clear liquid into a red liquid, then back to clear again. This demonstration is commonly called turning water into wine or blood, and can be used to demonstrate acid-base indicators.

How Is Moonshine Made?
Moonshine is a liquor made from fermented corn. Learn about distillation, condensation, and how this alcoholic beverage is made.

How Much Oxygen Does One Tree Produce?
You've probably heard that trees produce oxygen, but have you ever wondered just how much oxygen one tree makes? The amount of oxygen produced by a tree depends on several factors, but here are some typical calculations.

If civilization ended today, could I still make beer?
If civilization ended right now, could I still make beer? Learn about how beer is brewed and what is required to make this popular alcoholic beverage.

If I Leave My Goldfish in the Dark, Will it Turn White?
Learn about pigment biochemistry and find out whether your goldfish will turn white if you leave it in the dark long enough.

Is It Possible to Turn Lead into Gold?
Learn about transmutation, the holy grail of alchemy. Can one chemical be changed into another? Is it worth the effort?

Is It Safe to Use Kitchen Glassware for Chemistry?
Is it safe to use your kitchen glassware and utensils for chemistry experiments? Here's a look at some of the risks involved in using your dishes for chemistry.

Is It True that an MRI Will Make a Tattoo Burn?
Is a burning reaction between a tattoo and magnetic resonance imaging (an MRI) based in fact or is it an urban legend? Here's the answer!

Is There Really a Chemistry of Love?
Sweaty palms and a pounding heart don't just happen! It takes complex biochemistry to give you the symptoms of being in love. And lust. And security. Chemistry may even play a role in falling out-of-love. Get some of the details here, with links for further study.

What Are Examples of Endothermic Reactions?
Are you looking for examples of endothermic reactions for homework or to set up a demonstration? Here's a list of several heat-absorbing or endothermic chemical reactions and processes.

What Are Olympic Medals Made Of?
What do you think Olympic medals are made of? Are the gold medals really gold? They used to be solid gold, but now Olympic gold medals are made from something else. Here's a look at the metal composition of Olympic medals and how the medals have changed over time.

What Are Radiation Pills?
Radiation pills may be given in the event of nuclear accidents, nuclear attacks or in the course of certain radioactive medical treatments. Here's a look at what radiation pills are and what is in them.

What are Solutions, Suspensions, Colloids, and Dispersions?
Learn how to distiguish between solutions, suspensions, colloids, and dispersions. Get examples of the different types of mixtures.

What Are Some Careers in Chemistry?
Chemistry isn't just for chemists! Here's a nice long list of chemistry-related careers, along with a discussion on how your degree impacts your employment options.

What Are Some Chemistry Demos I Can Do?
This is the list of my personal favorite chemistry demonstrations and activities. They tend to involve pretty colors, fire, or ice. Some projects require adult supervision or access to a chemistry lab. Others are easy and safe enough for kids to perform.

What Are Some Examples of Polymers?
Do you need some examples of polymers? Here is a list of materials that are polymers, plus some examples of materials that are not polymers.

What Are Some Good Chemistry Projects for Kids?
Are you searching for something fun and educational to do that suitable for kids? Here are some great chemistry activities and projects to get you started. They are safe and use easy-to-find materials.

What Are Some of the Best Chemistry Forum Posts?
About Chemistry's Forum hosts some interesting and educational discussions. This is a collection of some of the best threads.

What Are the Alchemical Symbols of the Elements?
See the symbols of the elements and learn how alchemists used them.

What are the Chemistry Laboratory Safety Rules?
Make your chemistry laboratory experience safe by following these simple rules.

What Are the Elements in the Human Body?
Do you know the chemical composition of the human body? Here's the list of elements, given in percentage according to weight.

What Are the Names and Symbols of the Elements?
It's easier to navigate the periodic table and write chemical equations and formulae once you know the symbols for the elements. Here's an alphabetical list of element symbols with corresponding element names.

What Are the Periodic Properties of Elements?
The properties of the elements exhibit periodicity. Learn how to use the periodic table to predict the trends in atomic radius, ionization energy, electron affinity, and electronegativity.

What Are the States of Matter?
Get definitions and examples of the main states of matter: solids, liquids, gases, and plasma.

What Are the Top 25 Chemistry Features?
Not sure where to go? Then check out every else's favorites! These are the top 25 most-visited pages on the About Chemistry website.

What Are the Uses of Food Additives?
This is a list of common food additives and a description of their uses.

What Causes Brain Freeze?
If you've ever experienced a sudden stabbing pain in your forehead when eating ice cream or enjoying a cool drink then you know what brain freeze is. Do you know what causes brain freeze or how you can stop the pain?

What Causes Rigor Mortis?
Dead bodies are sometimes referred to as 'stiffs' for a reason! Learn what rigor mortis is and find out why it happens.

What Do s, p, d, and f Mean?
s, p, d, and f are orbital names that stand for sharp, principal, diffuse, and fundamental. This summary tells more about orbitals and electronic structure.

What Elements Are In the Body and What Do They Do?
Find out what elements are in the human body and what these elements do.

What Happens If I Touch Dry Ice?
Dry ice is solid carbon dioxide, which is extremely cold. You should wear gloves or other protective gear when you handle dry ice, but have you ever wondered what would happen to your hand if you touched it? Here's the answer.

What Home Chemicals Shouldn't Be Mixed?
Labs have lists of chemicals that don't go together, but it isn't as easy to avoid dangerous mixtures with home chemicals because they aren't pure substances. Here's some help. Be safe and don't mix these common household chemicals.

What Is a Chemical?
Are you wondering what makes a chemical a chemical? Here's the answer to this frequently asked chemistry question.

What Is a Chemical Element?
Get the definition for a chemical element.

What Is a Crystal?
Get the definition for a crystal and learn about some common types of crystals.

What Is a Mole and Why Are Moles Used?
No, we're not talking about the small burrowing mammal! Here's a look at a standard unit in chemistry and why it's used.

What Is a Neutron Bomb?
Learn what a neutron bomb is, how it works, and about a neutron bomb's strategic uses.

What Is Absinthe and What Made it Illegal?
Absinthe has been enjoying a resurgence in popularity, as countries lift the ban on making the green wormwood and anise-flavored spirit. Learn about the history of the liqueur, why it was banned, a bit about its chemistry, how to make absinthe, and how to drink it.

What Is Absolute Zero?
Learn about absolute zero and the Kelvin and Celsius temperature scales.

What Is a CAS Number?
Many molecules are identified by a number following a CAS prefix. What are these CAS numbers and what do they mean?

What Is Activated Charcoal and How Does it Work?
Activated charcoal isn't the same as your average barbeque briquette! It's a special type of carbon. Learn what activated charcoal is and why it is used in filters and medicines.

What Is an Atom?
Are you confused about atoms, elements, protons, neutrons, electrons, isotopes, and ions? Here's a basic look at the model of the atom. It's a great overview for kids or anyone looking to grasp the essentials of atomic theory.

What Is Bleach and How Does It Work?
Learn what a bleach is, get examples of different types, and find out how bleach works.

What Is Carnauba Wax?
Carnauba wax is an ingredient in many foods and household products. Here's a look at what carnauba wax is made of and the properties that make it such as useful chemical.

What Is Chemical Engineering? What Do Chemical Engineers Do?
Are you confused about how chemical engineering differs from pure chemistry or other types of engineering? Here's an explanation of what chemical engineering is and what chemical engineers do.

What Is Chemistry?
Here are long and short answers to this Frequently Asked Question.

What Is Crystal Meth?
Learn what crystal meth is, why people take crystal meth, how it's made, and what risks are associated with using methamphetamine.

What Is Distillation?
Distillation is a common chemistry process used to separate materials by changing their states of matter. Learn more about how the process works and find out about different types of distillations.

What Is Dry Ice?
Do you know what dry ice is? Learn about dry ice and find fun projects that use dry ice.

What Is Earth Day?
Find out what Earth Day is all about, when it is, and how it started.

What Is Fluoride?
Are you confused about the difference between fluoride and fluorine or simply want to know what fluoride is? Here's the answer to this common chemistry question.

What Is in Chewing Gum?
Learn about the ingredients in chewing gum and find out whether it's true gum stays in your stomach seven years if you swallow it.

What Is Radioactivity? What is Radiation?
Learn about natural and induced radioactivity and alpha, beta, and gamma radiation.

What Is Red Mercury?
Is it a secret, wildly explosive compound used to make deuterium-tritium fusion bombs for use by terrorists? Maybe there's a more conventional explanation...

What Is Reverse Osmosis?
This handy technique is used to desalinate seawater and purify bottled water. Find out how it works!

What Is Soap and How Is it Made?
Soap is a salt made from a chemical reaction between fat and sodium or potassium hydroxide. This article explains the saponification reaction both in words and with structure diagrams and provides links for further information.

What Is the Chemical Composition of Air?
Learn about chemical composition of the Earth's air. Percentages of the most common compounds are given, according to volume.

What Is the Clean Air Act?
You've probably heard about the Clean Air Acts and can figure out they have something to do with air pollution, but what else do you know about Clean Air Act legislation? Here's a look at the Clean Air Acts and answers to some common questions about them.

What Is the Clean Water Act?
Here's a look at what the Clean Water Act is and how this legislation is intended to address water pollution.

What Is the Coastal Dead Zone?
The coastal dead zone makes news headlines from time to time because it's implicated in fish death and may be a consequence of global warming and pollution. Do you know what the dead zone is?

What is the Difference Between a Chemical and Physical Property?
Learn how to distinguish between a chemical property and a physical property of matter.

What Is the Difference Between a Hypothesis, Theory, and Law?
Words have very specific meanings in chemistry and other sciences. Learn about the difference between a scientific law, hypothesis, and theory. Examples are provided for each term.

What Is the Difference Between a Scientist and an Engineer?
Scientist versus engineer: are they the same? Different? Here's a look at the definitions of scientist and engineer and the difference between a scientist and engineer.

What Is the Difference Between an Ionic and Covalent Chemical Bond?
Learn to distinguish between ionic and covalent bonds, and determine whether a bond will be polar or nonpolar.

What Is the Difference Between Baking Powder & Baking Soda?
Learn about the difference between these two common cooking ingredients, the effect of substitutions, and find out how you can use baking soda to make your own baking powder.

What Is the Difference between Strong and Weak Acids and Bases?
Learn about strong and weak acids and bases. Get definitions and examples of each type.

What Is the Freezing Point of Water?
What is the freezing point of water or the melting point of water? Are the freezing point and melting point the same? Are there any factors that affect the freezing point of water? Here's a look at the answers to these common questions.

What Is the Greenhouse Effect?
Learn what the greenhouse effect is and how it is related to climate.

What Is the IUPAC and What Does It Do?
Find out what the IUPAC is and learn a little about about what the IUPAC does.

What Is the Lightest or Least Dense Solid?
I'll give you a hint: it isn't styrofoam! The world's lightest solid resembles a sort of solid smoke, with a density of only 19 grams per liter.

What Is the Mohs Scale of Hardness?
The Mohs Scale of Hardness measures how well a substance resists scratching by another material. You can use this scale to test the hardness of rocks, minerals, and crystals, to help identify them.

What Is the Most Abundant Element?
The elemental composition of the universe and the earth's crust are very different! How different? Take a look...

What Is the Most Bitter Compound?
I've had some scorched coffee that I'm sure should have qualified for this award, but it turns out there's a real answer to this question of taste. Do you know what it is?

What Is the Most Poisonous Chemical Compound?
How poisonous something is depends a lot on how it's administered and a several other factors, but this list will give you a general look at some of the most toxic substances known to man.

What Is the Nobel Prize Medal Made Of?
The Nobel Prize medal looks like gold, but what is it really made of? Here's the answer to this common question about the composition of the Nobel Prize medal.

What is the pH of a Common Chemical?
Here's a table of the pH of several common chemicals. You can use the list to set up color ranges for pH indicators or simply to learn more about acids and bases.

What Is the Scientific Method?
Science fair and research projects apply the scientific method. Here's an informal explanation of the scientific method and how it is used.

What Is the Smelliest Chemical?
There are some man-made chemicals with a stench well beyond the gentle perfume of dirty gym socks and skunk spray. Do you know the names of these super-stinkers?

What is the State of Matter of Fire?
What is the state of matter of fire or flame? Is it a liquid, solid, or gas? Learn the answer to this question and get information about the chemistry of fire.

What Is the Strongest Acid?
Do you know what the strongest acid is? I'll give you a hint. It's not hydrochloric acid nor is it sulfuric acid.

What Is Tin Cry?
Learn about tin cry. Find out what tin cry is and why it occurs. Also, here is a demo in which you can make tin cry repeatedly.

What Is the Sweetest Compound?
Did you know there are sweeteners that are 200,000 times sweeter than table sugar? Take a look at this list to find out how your favorite sweetener rates.

What Is the Wavelength of Magenta?
Have you ever tried to find the color magenta on the visible spectrum? You can't do it! There is no wavelength of light that makes magenta. So how do we see it? Here's the answer to the question.

What Is the Volume & Chemical Composition of Blood?
Do you know how many liters of blood are in your body? How about what's in your blood? Let's learn about the chemistry of human blood.

What Is the World's Most Venomous Insect?
The most venomous insect isn't some rare, exotic rain forest creature. You may have them in your own yard. Can you name guess what it is?

What Makes Lead Poisonous?
You probably know that lead is toxic, but do you know what makes it poisonous? Here's an explanation of what lead does in your body that makes it such a health hazard.

What Materials Glow Under a Black or Ultraviolet Light?
Black lights emit ultraviolet radiation, giving certain materials an eerie glow. Which materials? You can do a little experimental research or you can check out this list!

What Temperature Does Water Boil?
At what temperature does water boil? What determines the boiling point of water? Here's the answer to this common question.

What Was Project Stormfury? Can Cloud Seeding Dissipate Hurricanes?
One way scientists have tried to lessen the severity of hurricanes is by seeding the clouds with silver iodide. This research program was Project Stormfury. Learn whether cloud seeding worked and why the program was discontinued.

Where Are the 2001 Chemistry Articles?
This is a collection of all of the original feature articles written for About Chemistry in 2001. The articles include information on gasoline, preservatives, theobromine, lycopene, diamond structure, soap-making, and many other topics.

Where Are the 2002 Chemistry Articles?
This is a collection of all of the original feature articles written for About Chemistry in 2002. The articles include information on tattoo ink, science fair projects, Nobel prizes, Avogadro, leaf colors, sunless tanning, and more.

Where Are the 2003 Chemistry Articles?
This is a collection of all of the original feature articles written for About Chemistry in 2003. The articles cover group chemistry, rock tumbler instructions, sports drinks, natural mosquito repellents, and more.

Where Are This Year's Chemistry Articles?
These are the most recent feature chemistry articles written by your Guide.

Where Can I Find Chemical Structures?
From your About Chemistry Guide, these are structures (gifs) for all of the molecules from articles and facts on the About Chemistry website. Many supplemental structures are available, too. Additions are made to the archive regularly.

Where Can I Find Chemistry Site Help?
Do have questions or need help? Start here to get answers to common questions and find resources to help solve your problem.

Where Can I Find Worked Chemistry Problems?
This is an ever-growing collection of worked chemistry problems. The examples are grouped according to subject matter.

Where Do I Find Definitions for Chemistry Terms?
From your About Chemistry guide, this glossary includes terminology from featured articles. Additional chemistry definitions are always being added.

Where Does the Wax Go When You Burn a Candle?
Learn about the chemistry of combustion.

Where is Chemistry 101? How Do I Learn Chemistry?
Here's a listing of all of the introductory chemistry articles created by your Guide, as well as study and lab tips.

Where is the Periodic Table of the Elements?
You can't do chemistry without it! Find element facts and figures and examine trends in groups of elements.

Which Elements Are Named for People?
Alphabetical list of the chemical elements named after people.

Which Elements Are Named for Places?
Alphabetical list of elements in chemistry named for places or element toponyms.

Which Fruits Ruin Jell-O?
If you add certain fruits to Jell-O or other gelatin desserts, the gelatin won't set up. Here's a look at which fruits have this effect and what happens that causes them to ruin Jell-O.

Who Invented the Periodic Table?
Do you know who described the first periodic table of the elements that ordered the elements by increasing atomic weight and according to trends in their properties? I'll give you a hint. It was not Dmitri Mendeleev. The actual inventor of the periodic table is someone rarely mentioned in chemistry history books.

Who Is Anne Helmenstine?
I'm Anne Helmenstine, your Chemistry Guide. You can read about me here.

Who Made Chemistry Discoveries? When?
Find out who did what and when they did it. This timeline chronicles achievements in chemistry and in other disciplines (e.g., physics, mathematics) as they apply to chemistry.

Why Are Babies Born with Blue Eyes?
Do you know the answer? It's a matter of chemistry as much as biology. I've included other factoids about eye color, including some that may surprise you.

Why Are Flamingos Pink?
Have you ever wondered why flamingos are pink or orange? You've probably heard it has something to do with what flamingos eat, but do you know what exactly it is that produces the color?

Why Are Phosphates Used in Cleaning?
Here's a question and answer from the About Chemistry forum.

Why Do a Science Fair Project?
There are excellent reasons why you would want to do a science fair project, even if it isn't for a grade.

Why Do Batteries Discharge More Quickly in Cold Weather?
Batteries don't work equally well in hot weather and cold weather. Learn about the effect of temperature on battery performance.

Why Do Clothes Wrinkle?
Learn why clothes wrinkle and how permanent press fabrics work. It's a matter of polymer chemistry and chemical bonding.

Why Do Cut or Bruised Apples Turn Brown?
Learn why apples, pears, bananas, potatoes, and other fruits and vegetables turn brown when they are cut or damaged.

Why Do Leaves Change Color in the Fall?
Find out why leaves change color in the fall. Learn about the different pigments found in leaves and how bright autumn foliage is produced.

Why Do Onions Make You Cry?
Find out why you cry when you cut onions and how you can keep it from happening.

Why Do People Tap on Cans?
When you tap on the top of an unopened carbonated beverage you reduce the chance that it will spray all over you upon opening. Your About Chemistry Guide explains what happens and how it works.

Why Does Hair Turn Gray?
Have you ever wondered why hair turns gray as you get older and whether there is something you can do to prevent graying or at least slow it down? Here's a look at what causes hair to turn gray and some of the factors that affect graying.

Why Does Ice Float?
Learn about hydrogen bonding and density to understand why ice floats on water.

Why Does Pineapple Ruin Jell-O?
Have you heard that adding pineapple to Jell-O or other gelatin will prevent it from gelling? It's true. The reason pineapple prevents Jell-O from setting is because of its chemistry. Learn about what is in pineapple that causes this to happen.

Why Does Salt Melt Ice?
You know that you can sprinkle salt on an icy road or sidewalk to help keep it from becoming icy, but do you know how salt melts ice? Take a look at freezing point depression to understand how it works.

Why Does the Pool Turn Blonde Hair Green?
Do you think it's the chlorine in the swimming pool that turns blonde hair green? Guess again.

Why Doesn't the Flu Vaccine Always Work?
A new study conducted by the CDC indicates that getting the flu vaccine doesn't protect you against cold, flu-like illness, or even the flu. Surprised? Here are some reasons why the vaccine may not work.

Why Doesn't Vodka Freeze in the Freezer?
Why doesn't vodka freeze when you put it in the freezer? The answer to the question has to do with the chemical composition of vodka and a phenomenon known as freezing point depression.

Why Is It Harder to Rinse off Soap with Soft Water?
Soap lathers better in soft water, yet it's harder to rinse off than if you rinsed with hard water. Why? The answer lies in understanding the chemistry of soft water and soap.

Why Is Stainless Steel Stainless?
Learn about the chemistry of stainless steel. This article, from your About Guide, also includes descriptions of the different types of stainless steels, comments on passivation, and numerous links to sites offering related information.

What Is the Chemical Composition of Urine?
Urine is a liquid produced by the kidneys to remove waste products from the bloodstream. Human urine is yellowish in color and variable in chemical composition, but here is a list of its principal components.

What Is the Wavelength of Ultraviolet Light?
Ultraviolet light is light or electromagnetic radiation that occurs between the visible spectrum and x-rays. Here's a look at the wavelength range that is considered to be ultraviolet light.

Why Is the Ocean Blue?
Have you ever wondered why the ocean is blue? Have you ever wondered why the ocean is sometimes another color, like green, instead of blue? Here's the science behind the color of the sea.

Why Is the Ocean Salty?
Have you ever wondered why the ocean is salty? Have you wondered why lakes might not be salty? Here's a look at what makes the ocean salty and why other bodies of water have a different chemical composition.

Why Do Rings Turn My Finger Green?
Has a ring ever turned your finger green, black, red or some other color? Share your experience. What color did your finger turn? What type of ring were you wearing? Are there some types of rings that work better for you than others?

What Is The Formula For Charles' Law?
Charles' Law is a special case of the ideal gas law. This law only applies when the volume and temperature of a gas is allowed to change while the pressure is held constant.

What Is The Formula For Boyle's Law?
Boyle's Law is a special case of the ideal gas law. This law only applies to ideal gases when the volume and pressure are allowed to change while the temperature is held constant.

What Is The Formula For Gay-Lussac’s Law?
Gay-Lussac's Law is a special case of the ideal gas law. This law only applies to ideal gases where the pressure and temperature are allowed to change while the volume is held constant.

What is Dalton's Law of Partial Pressures?
Dalton's law of partial pressures is used to determine the individual pressures of each component gas in a mixture of gases.

What Is The Formula For The Combined Gas Law?
The combined gas law examines the behavior of an ideal gas when pressure, volume and/or temperature is allowed to change.

What Is The Formula For Graham's Law of Diffusion and Effusion?
Graham's law of diffusion and effusion expresses the relationship between the rate of effusion or diffusion of a gas and its molar mass.

What Is The Difference Between Diffusion and Effusion?
A when a volume of gas is allowed to expand into another volume with less pressure, the gas can either diffuse or effuse into the container. The main difference between diffusion and effusion is the barrier between the two volumes.

What Is The Rydberg Formula?
The Rydberg formula is a mathematical formula used to predict the wavelength of light resulting from an electron moving between energy levels of an atom.

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