This category encompasses all questions about the composition, structure, properties, and reactions of matter.
Asked in Science, Chemistry, Periodic Table
What is the fourth element of the periodic table of elements?
Asked in Science, Chemistry, Acids and Bases
What are some examples of chemical and physical changes?
Physical Changes Change of state (such as from solid to liquid or from gas to liquid) Specific examples of state change include water freezing, alcohol evaporating and dry ice (solid carbon dioxide) subliming Absorption of water into a towel Crumpling a piece of paper Pulling copper into a thin wire - a change of shape, but not a change of composition Cutting a material such as wood Tearing a piece of tin foil Breaking glass Deflating a basketball Mixing different solids (such as solid sulfur and iron filings) Inflating a volleyball Cloud forming in the sky Chemical changes Burning a log of wood Mixing an acid with a base, producing water and a salt. Photosynthesis - a process in which carbon dioxide and water are changed into sugars by plants. Cracking heavy hydrocarbons to create lighter hydrocarbons (part of the process of refining oil). Cooking examples: popcorn, cake, pancakes, and eggs Oxidation examples: rust or tarnishing Combustion Mixing chemicals Rotting of fruit Cooking rice Explosion of fireworks Tarnishing silver Lighting a match Chewing/digesting food Rusting nail Burning gas in a stove Oxidizing food for energy Roasting a marshmallow Adding food coloring to icing Frying an egg Burning a magnesium strip The following can indicate that a chemical change took place, although this evidence is not conclusive: Change of color (for example, silver to reddish-brown when iron rusts) Change in temperature or energy, such as the production (exothermic) or loss (endothermic) of heat Change of form (for example, burning paper) Light, heat, or sound is given off Formation of gases, often appearing as bubbles Formation of precipitate (insoluble particles) The decomposition of organic matter (for example, rotting food)
What type of element is a protactinium?
I'm not too bad at chemistry, but one thing I can't wrap my head around is how perfect the periodic table is. How is it that each element that we know is only one more proton than the last? How come it goes in PERFECT order instead of having a few elements with protons not perfectly linear to the periodic table?
How do you determine if a molecule is polar or non-polar?
Polar Bonds and Molecular Shape A polar molecule is a molecule that has a net dipole moment due to its having unsymmetrical polar bonds. There are two factors that go into determining if a molecule is polar or not. To determine if a molecule (or ion) is polar or non-polar, you must determine both factors. The polarity of the individual bonds in the molecule. The shape or geometry of the molecule. First, to determine if a given individual bond is polar, you need to know the electronegativity of the two atoms involved in that bond. To find the electronegativities of all the elements, look at the periodic table (follow the link below this answer under Web Links). If the electronegativity of the two atoms has a difference of 0.3 or less, then the bond is non-polar. If the electronegativity difference is greater that 0.3 but less than 1.7, then the bond is polar. If the two values have a difference greater than 1.7, then the bond is ionic, which is just very very polar. Once you know which bonds in the molecule are polar and which are non-polar, you must use the shape of the molecule. You need the shape because two polar bonds, if oriented correctly can cancel each other out (like two equally strong people pulling in opposite directions on a rope -- nobody moves). The three possible outcomes: If all bonds are non-polar, then the whole molecule is non-polar regardless of its shape. If there is symmetry in the molecule so that the polarity of the bonds cancels out, then the molecule is non-polar. A common example of this is carbon dioxide, or CO2. The molecule is linear, and its Lewis dot structure is like this: O=C=O (this doesn't include two sets of lone pairs on each oxygen). The carbon-oxygen bond is a polar bond, but because they are exactly opposed to each other, the molecule is overall non-polar. Another example of this is CCl4, where each carbon-chlorine bond is polar, but the molecule is non-polar. Here, how they cancel out isn't as obvious, but they do. CCl4 is a tetrahedral molecule, and the 4 C-Cl polar bonds cancel each other out. If there are polar bonds but there is no symmetry such that they cancel each other out, the overall molecule is polar. Water is a typical example of this. The two O-H bonds are oriented in a V-shape, and so the don't cancel out. Similarly, CH3Cl is also polar. It is the same shape as CCl4 (see above), but now it doesn't have the same symmetry because there is only one C-Cl bond and the bonds don't cancel out anymore.
What is the percent error formula?
Percent Error is the difference between the true value and the estimate divided by the true value and the result is multiplied by 100 to make it a percentage. The percent error obviously can be positive or negative; however, some prefer taking the absolute value of the difference. The formula is the absolute value of the experimental value (minus) the theoretical value divided by theoretical value times 100. % error = (|Your Result - Accepted Value| / Accepted Value) x 100
Which science is the most complex chemistry or biology or physics?
Chemistry is an important branch of Science and it discusses the reactions of chemical elements in human body. Learning Chemistry needs skills like attention, hard work and determination which an online Chemistry tutor inculcates in a student. For me science is basic and I truly appreciate science so I would state that the trouble level is about the equivalent in spite of the fact that science utilizes a considerable amount of maths and you have to comprehend ideas so as to utilize them while science is content substantial. having said that, science mark plans are exceptionally particular with watchwords and granting marks...
Asked in Chemistry, Gold and Precious Metals
What is the formula of white gold?
Well,white gold never existed, but any industry to create the best white gold formula alloys is the one go to make big money. Because the consumer is looking for the best precious metal alloys; any person that has his or her own real pure solid white gold formula alloys, is not in their best interest to specify the formula to any other person. In this world we have more that 181 precious metals to combine to produce your own white gold formula; you only make sure when you find the formula that pass the acid,and magnet test, you can make jewelry to not loose the white color for life. Yellow gold with Rhodium is not real pure color white gold. You do not need yellow gold to create the karat 10k threw 21k to past the acid and magnet test.With all the problem to create yellow gold with Rhodium the jewelry industry, lied to the consumers that it is white gold when its not. Now we have to guaranty the pure solid white gold formula alloys for life time, or money back guaranty! Think good Wake Up. Real pure solid white gold formula alloys precious metals is the best to create white gold, and that it is not yellow gold alloys with Rhodium. Sincerely, see web page. Living Life Enterprises Presents. For the best interest to the consumers.
10 examples of physical change and chemical change?
Physical Change: *Milo dissolves into hot milk *A plate is dropped and shatters *Grass in mowed *Metal Knife is sharpened *Breakfast Cereal goes soggy Chemical Change: *Wood burns to form black charcoal * A green tomato ripens and turns red * Fireworks explode to form colourful light and loud sounds * Vegetables scraps in the compost bin decompose to form rich soil * An egg is cooked to become a white and yellow solid
Asked in Chemistry, Law & Legal Issues
What gas law applies to aerosol cans being stored in a cool place?
Don't really know if this is what your asking but P1/T1= P2/T2 should show how the pressure varies with temperature (V is left out because it's constant since the gas is trapped in an aerosol can). As the temperature rises the pressure rises and if it gets too high then the can explodes, which is why it should be stored in a cool place. There's also PV=nRT might be kind of hard to find moles (n) though. the ideal gas law will provide a rough estimate for the P V T properties of the vapor in the cans. ________________________________________________ Edit by: Bipolarattorney 08/17/12 From a legal perspective, in the United States, the Occupational Safety & Health Administration (OSHA) would govern the requirement to safely/properly store hazardous materials. The Code of Federal Regulations, which would apply, is 29 CFR 1910.
What does Fe500 steel mean?
The abbreviation Fe stands for Ferrous material ie iron from which the reinforcement steel bars are manufactured. The reinforcement steel bars used in RCC (Reinforced Cement Concrete) are designated as Fe415 or Fe500 depending on their Yield Strength. (The numbers 415 and 500 tell about this Yield Strength in N/mm2 the bars are designed and manufactured to have.) As per IS : 1786 Yield Stress (also known as 0.2% proof stress) of Fe 500 is 500 N/mm2. So, Fe500 steel means the reinforcement steel rods (or bars) that can safely withstand an Yield Stress of 500 N/mm2.
Asked in Chemistry, Philippines
Who are some famous Filipino chemists and what are their contributions to the field of chemistry?
Filipino Chemists and their contributions Julian Banzon - experimented with the production of ethyl ester fuels from sugarcane and coconut and invented a means of extracting residual coconut oil by a chemical process rather than a physical process. A pioneer for alternative fuels ROM the 1930's and 40's. Francisco Quisumbing - invented Quink ink (currently used in Parker Pens) which is a quick drying ink that prevents the ink from clogging the pen. Ramon Barba - created crop flowering techniques using a potassium nitrate spray. Due to his discoveries in tropical tree physiology, the Philippines is the leading exporter of mangoes and mango products. Francisco Santos - studied the nutritive values and chemical composition of local foods from the Philippines. His data was used to help detect and solve problems with Filipino diets. Rolando De La Cruz - inventor of an anti-cancer skin cream. Anacleto Del Rosario - Winner of first prize at the World Fair in Paris in 1881 for for producing a pure alcohol from tuba of a nipa palm. His research also led to the process of extracting castor oil from a native plant called palma christi. Alfredo Santos - isolation and elucidation of biochemicals (the phaeantharine and other alkaloids) from Philippine medical plants. Eduardo San Juan - worked on the team that invented and launched the Lunar Rover (Moon Bugg) Daniel Dingel - possible invention of a water-powered car Benjamin Almeda - designed a cutting edge food-processing machine More Filipino Scientists that have contributed to the field of chemistry: Lourdes J. Cruz Dr. Beatrice Guevara Dr. Evelyn Mae T. Mendoza Dr. Elma C. Llaguno Lani Rose Mateo Richard Sucgang Angel Arguelles Julian Bazon Luz Oliveros-Belardo Alfredo Santos
Asked in Science, Physics, Chemistry, Chemical Bonding
Why does water have a high and specific heat capacity?
First, we need to know a little bit about water. Water is a polar molecule because oxygen bears partial negative charge and hydrogen bears partial positive charge. This results in extensive hydrogen bonding in water molecules between slightly negative oxygens and slightly positive hydrogens. Second, we need to remember that temperature is another way of saying the average kinetic energy of particles - the higher the temperature, the faster they move, in the case of gases and liquids, or vibrate, in the case of solids. Third, heat capacity is the ability of matter to absorb thermal energy. One calorie is defined as the amount required to heat a gram of water one degree Centigrade. That same calorie will heat a gram of gold 33 degrees. Water's specific heat is defined as 1. The specific heat of gold is therefore .03. Water has a high specific heat because there are quite a few ways water can store heat. 1. Moving along three axes 2. Rotating the "V" shaped molecule in three different directions 3. Hydrogen atoms vibrating back and forth like a tuning fork 4. Hydrogen atoms vibrating up and down along their H-O axis. Finally, the heat of fusion of water is 80 calories per gram, and the heat of vaporization for water is 540 calories. So ice can absorb 80 times as much heat while melting as the same mass of water. Water absorbs 540 times as much heat while turning into water vapor as the same mass of water absorbs. Both phase changes occur at constant temperature, 0 Centigrade and 100 Centigrade respectively. Look up phase change graph for water to see the interesting line.
Asked in Cleaning, Chemistry, Manicures and Pedicures
How do you remove nail polish stains from your carpet?
Removing nail polish stains from your carpet wont take much time if used with right strategy and cleaner. A quality carpet cleaner with industrial strength can help you removing this tough nail stain marks. You can use a spong cloth and apply little ammount of high strength carpet cleaner to the stained area and start scrubbing in circular morion. Rinse the affected or spotted area with water and leave it open to get dry. This stain should disappear.
Asked in Math and Arithmetic, Chemistry
What are negative ligands?
Asked in Chemistry, Elements and Compounds
How will you justify water is a compound?
See related questions. Water is made up of elements Hydrogen and Oxygen with the chemical formula: H2O. It can easily be disassociated with electrolysis into the elements Hydrogen (H2) and Oxygen (O2), and reformed with combustion. It has aspects of both covalent and ionic bonds. It is generally considered neutral, but can be a proton donor to act as a weak acid. H2O --> HO- + H+. It can also act as a weak base, being a proton acceptor. H2O + H+ --> H3O+.
Asked in Chemistry
Is sperm good for your skin?
== == First of all, lets assume you mean semen. Sperm are the little swimming guys you see in reproduction videos; semen is the lubricative substance that surrounds them and can exist free of sperm. Yes, it is good for the skin. Semen is not only rich in vitamin "E" but it is a natural lubricant that moisturizes the skin and causes it to glow. * The reported 'salty' taste is from ammonia salts picked up from the urethra, these salts are very effective at de-greasing as well as having anti-bacterial properties. * However, it also has a very distinct odor of musk which may be undesirable. * Just an FYI- skin cream is easily available in stores.
Asked in Chemistry
Is air a mixture or a solution or a compound or an element?
Air is a mixture of gases (and not a compound), about 78% being nitrogen (an element) , about 21% oxygen (another element), and all other gases present in much lesser amounts. The remaining 1% is made up of argon (0.93%), carbon dioxide (0.039% as of 2010) and other trace gases (0.003%). Water vapor (water in its gaseous state) is also present in the atmosphere in varying amounts, by up to 2%. If you live in Florida in the summer rains, or in parts of England, or in the rain forest, humidity is high, and the air contains a large amount of water vapor. In dry air, as that found in desert regions, there is little water vapor in the air. This mixture is fairly homogeneous near the surface, and the only practical way to separate the individual gases is by cooling them to their condensation temperatures, which are extremely low. One of the easier gases to condense is carbon dioxide, which changes to solid form at about - 78.5 °C and is known as "dry ice." These components exist in air as separate, unreactive, and unbound entities (molecules). If air was a compound, the above mentioned gases would be chemically bonded together in some sort of fixed ratios (like H20), which they're not.
Asked in Chemistry
What are the names and uses of the various laboratory tools?
Laboratory Tools and Apparatuses Tools include beakers, microscopes, tweezers, hot plates, lasers, volt meters, test tubes, Erlenmeyer flasks, thermometers, test tube racks, Bunsen burners, crucibles, tripods and more. They are used to measure, observe and gather data for experiments, as well as to safely perform reactions and to heat things. More advanced laboratory equipment includes items such as spectrometers, centrifuges and chromatographs. Of utmost importance are these safety tools: Eye wash: In case materials get into your eyes, use this to rinse them out. Safety shower: In case materials get onto your clothing or body, use this to rinse them off. Tools and their uses: beaker - a liquid-measuring container burette - measures volume of solution clay triangle - a wire frame with porcelain used to support a crucible wire gauze - used to spread heat of a burner flame test tube - used as holder of small amount of solution forceps - holds or pick up small objects graduated cylinder - measures approximate volume of liquids graduated pipette - measures solution volumes condenser - used in distillation crucible - used to heat a small amount of a solid substance at a very high temperature funnel - used to transfer solids and liquids without spilling thermometer - measures temperature balance - measures mass of material pH meter - measures acidity of solutions centrifuge - separates materials of varying density pipette - used to transfer measured substances into another vessel droppers - for addition of liquids, drop by drop glass funnels - for funneling liquids from one container to another, or for filtering when equipped with filter paper. graduated cylinders - for measurement of an amount of liquid. The volume of liquid can be estimated to the nearest 0.1 mL with practice. ring stand (with rings or clamps) - for holding pieces of glassware in place. test tubes - for holding small samples or for containing small-scale reactions test-tube holders - for holding test tubes when tubes should not be touched tongs - similar function to forceps, but are useful for larger items volumetric flasks - to measure precise volumes of liquid or to make precise dilutions. wash bottles - for dispensing small quantities of distilled water. watch glasses - for holding small samples or for covering beakers or evaporating dishes. wire gauze on a ring - supports beakers to be heated by Bunsen burners For more information on these tools, see the Related Questions and the Related Links.
Asked in Chemistry, Science, Sports
Why is science defined as a product and a process?
This is because science is not just the information presented (the product), but also the way in which that information has been collected (the process). While scientific knowledge should be testable and falsifiable (according to Karl Popper), the way in which such information has been gathered is also important. Science should be unbiased and experiments should be repeatable by different individuals. There are different philosophers who argue on the way science proceeds. (see Popper, Kuhn, Lakatos and Feyerabend)
What is orbital mixing?
Asked in Chemistry, Acids and Bases, Metal and Alloys
What happens when dilute acids react with chemically active metals?
Asked in Chemistry
What organisms use energy from the sun or stored in chemical compounds to manufacture their own nutrients?
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