This category encompasses all questions about the composition, structure, properties, and reactions of matter.
Asked in Chemistry, Military Awards and Medals, Cigarette Lighters, English Spelling and Pronunciation
What does 'plaque OR g 10 microns' mean on a medal?
It has so do with the amount of gold plating is on an item lets say a watch, you take it to the jewelers and by knowing how many microns the gold layer is he can effectively polish your watch or whatever it may be with out hitting the base metal there is a sight that explains it better and gives examples of micron thickness as compared to . You just have to search it out.
Asked in Chemistry, Organic Chemistry, Acids and Bases
Why para nitro phenol is more acidic than meta nitro phenol?
Para nitrophenol is more acidic than meta nitrophenol because the deprotonated cation for the para form is able to delocalize the positive charge over the ring AND the nitro group, whereas the meta form is only able to delocalize over the ring. Thus the para ion is more stable, so the products for an acid-base reaction are more favoured for the para than for the meta.
Asked in Chemistry, Biochemistry
What are the Biological properties of Water?
Water is a chemical substance with the chemical formula H2O. Its molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state, water vapor or steam. Water covers 70.9% of the Earth's surface, and is vital for all known forms of life. On Earth, it is found mostly in oceans and other large water bodies, with 1.6% of water below ground in aquifers and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation.Oceans hold 97% of surface water, glaciers and polar ice caps 2.4%, and other land surface water such as rivers, lakes and ponds 0.6%. A very small amount of the Earth's water is contained within biological bodies and manufactured products. Water on Earth moves continually through a cycle of evaporation or transpiration (evapotranspiration),precipitation, and runoff, usually reaching the sea. Over land, evaporation and transpiration contribute to the precipitation over land. Clean drinking water is essential to human and other lifeforms. Access to safe drinking water has improved steadily and substantially over the last decades in almost every part of the world. There is a clear correlation between access to safe water and GDPper capita. However, some observers have estimated that by 2025 more than half of the world population will be facing water-based vulnerability. A recent report (November 2009) suggests that by 2030, in some developing regions of the world, water demand will exceed supply by 50%. Water plays an important role in theworld economy, as it functions as a solvent for a wide variety of chemical substances and facilitates industrial cooling and transportation. Approximately 70% offreshwater is consumed by agriculture. Water is a polar molecule (this means that the distribution of charges through the molecule isn't even). The hydrogen atoms have partially positive charges (δ +) and the oxygen atoms have partially negative charges (δ -). These charges form very strong bonds between molecules of water (Hydrogen - oxygen) called hydrogen bonds. A covalent bond is formed between the oxygen (group 6) and two hydrogen atoms (group 1). Property: Reason/ explanation: Application: High specific heat capacity Specific heat capacity is the amount of energy that it takes to raise the temperature of 1kg of a substance by 1 degree. Temperature relates to the amount of kinetic energy that the molecules within a substance have. As there are very strong hydrogen bonds between the water molecules, it takes a lot of energy to break them. As a result of these strong hydrogen bonds, more of the energy goes into breaking them rather than raising the temperature of the water. Therefore the amount of energy needed to raise the temperature of 1kg of water by 1 degree is relatively high so it has a high specific heat capacity. The high specific heat capacity is why water has a high boiling point and is a water at room temperature. Water in our bodies works as a temperature buffer. This means that it keeps our bodies as close to 37 degrees most of the time. This is because if, for example the temperature of the surrounding environment increases or the rate of respiration rises à exercise, then the temperature of our bodies does not increase. (There is a high percentage of water in our bodies). A constant body temperature is important for homeostasis to stop our enzymes from denaturing. Latent heat of evaporation In a body of water, some molecules are moving faster than others because they have more kinetic energy. Some of these molecules have enough kinetic energy to leave the body of water. As this water leaves the body of water it takes a lot of the energy from the total body of water with it (as they are taking kinetic energy with them and therefore the temperature of the body of water falls). This is why water evaporates in the sun after it has rained even though the water isn't boiling. This process is important in bodies of animals because the evaporation of sweat helps to cool down the body. It is also has effect on the leaves in plants as it removes water from leaves. Strong Cohesion Cohesion Is when molecules attract to each other (because of the partial charges of the hydrogen and oxygen atoms). In a body of water, all of the molecules are attracted to each other, however, the uppermost molecules only have forces from beneath. Therefore, the uppermost molecules are pulled further down and closer together (laterally). This creates surface tension on a large body of water. These strong attractions are important in the xylem as it allows water to flow in a continuous stream so the water can be taken up from root to leaf. Important solvent. As water is a polar molecule, it is therefore an important solvent. This is because the partially positive and negative charges attract atoms in other molecules causing them to separate and therefore dissolve. à When substances are dissolved in water they are free to move around and react with other molecules. Metabolic processes (i.e. respiration or photosynthesis) which are essential for any life can only happen when reactants are dissolved in water. For example the movement of Oxygen into our blood. Density When water freezes it turns to ice, which is less dense than when it is a liquid. This is because the hydrogen bonds formed are slightly further apart (due to the polarity) than that distance in water. This produces a giant, rigid open structure where every oxygen atom is at the centre of a tetrahedral arrangement (surrounded by hydrogen atoms). The lower density as a solid is why ice floats on water and doesn't sink. Adhesion The cohesive forces of water are related to the property of strong adhesion. Adhesion is the attraction between water molecules and other molecules - these forces can sometimes be stronger than cohesion. When water is within charged surfaces, for example the type that are found on the inside of a capillary tube, the water 'climbs' up the tube. This is because the water molecules are attracted to the charges on the insides of the capillary walls more than they are to each other.
Asked in China and Chinese Territories, Chemistry
What is a product made from xylene?
Xylene is generally used as a solvent. It is often encountered as a mixture of three different isomers, (same composition different structure), which are generically dimethylbenzenes. Para-xylene (1, 4 dimethyl benzene) can be oxidised toterephthalicacid which is then used for manufacture of PET plastiic. Xylenes can be chlorinated to form disinfectants (PCMX).
Asked in Chemistry
What is waterline corrosion?
Waterline corrosion: when water is stored in a metallic tank, it is observed that the metal below the waterline gets corroded. It is because the water below the waterline is poorly oxygenated and acts as an anode. The metal above the waterline is highly oxygenated and acts as a cathode. Hence corrosion of metal below the waterline takes place. Any other questions skype me christianschulte6474 or email me at email@example.com
Asked in Chemistry, Elements and Compounds
Name two compounds in unpolluted air?
Carbon Dioxide is present in unpolluted air. Methane (animals grazing literally fart this out) is also present and Nitrogen oxides formed when lighting strikes. The electrical discharge is high enough to cause oxygen and nitrogen to combine. It is basically a natural fertilizer In unpolluted air these compounds are present at levels of about 390 parts per million, 1.8 parts per million, and 1 part per billion respectively. The most abundant and most important compound in unpolluted air is ... water vapour -- present at levels which vary between about 0.1% and 5%, depending on temperature and humidity.
Asked in Chemistry
What factors cause iron to rust?
Corrosion: When iron is exposed to water and oxygen, it corrodes. The corrosion products are the familiar red-brown rust. Indoors, a certain amount of moisture in the air (above about 65% relative humidity) is usually required before iron will rust. However, corrosion may occur at lower relative humidity if the object's surface is contaminated with salt, dust, or other pollutants. Some iron objects have acquired an adherent rust layer from past exposure to high levels of moisture. This rust layer is often stable and will help slow corrosion of the underlying metal if the object is accidentally exposed to high moisture levels. Salt or other contaminants in the rust layer will stimulate further corrosion, especially at higher relative humidity. A sign of ongoing corrosion is flakes or loose powdery rust surrounding an object. Salts and oils on the skin can produce exactly the kind of corrosive environment that causes iron to react. Also, exposure of iron objects to cooking materials such as salts and sauces can accelerate corrosion. If the iron object in question is considered valuable, it should not be used as it was in the past. It should be protected from excessive handling and kept in a dry location. Attics, basements and garages are not good places to store iron objects because of fluctuating environmental conditions. Iron has been used for several thousand years in many different forms. It can be wrought by hand, cast into moulds, or formed through a wide range of modern factory processes. It is the most common metal in collections and appears universally in every household. All common metals are derived from their natural ores by a process called smelting. Iron ores are very stable chemical substances, but when smelted a great deal of energy is put into them to produce the metal. The metal is, therefore, more reactive and less stable and would return to the stable state if it could. We know by observation that metals are relatively unstable - they will rust and tarnish if allowed to do so. This process is called oxidation, although it is not always oxygen that is responsible. As iron oxidizes it moves quite slowly to states of lower energy where it is less reactive and thus more stable. Iron is converted to steel by adding carbon or other trace elements. In fact, objects of pure iron are very scarce. Working iron during forging introduces carbon as a by-product, resulting in the production of steel. So even wrought iron objects made by blacksmithing are actually made of low carbon steel. Early smiths used this property to advantage, adjusting the amount of forging to make composite sword blades with hard edges and flexible cores. Cast iron objects actually contain quite a high proportion of carbon; as much as 4% in some cases. Thin sheet steel is one of the most common forms of iron, appearing in a wide range of artefacts from lamps and stoves, to cooking ware and containers. Steel is also plated with tin or zinc to give it better protection from the environment. What Is Rust? Many materials react with oxygen to form a chemical compound that is a combination of that material and oxygen. When iron combines with oxygen, it forms iron oxide, or rust. Iron oxide is a larger molecule than iron, so if iron oxidizes, it often puffs up and may even flake. This is because the rust requires more physical space than the original iron. Some things cause steel or iron to rust faster than others. Water will cause iron and steel to rust. Dissimilar metals rust faster than single metals because of electrochemical reactions, so steel rusts faster than iron, and joints between dissimilar metals rust very quickly. Salt water will cause rust faster than water because salt water is a better electrical conductor. Like most chemical reactions, heat also speeds rust. If steel starts to rust, it will puff up because iron oxide is a larger molecule than iron. The puffing causes cracks and voids, which expose more bare metal to the environment. So the rusting of iron can progress and is only limited by destruction of all solid iron. Other metals oxidize, but the oxides of some other metals are no larger than the metal themselves, so they don't puff up or flake. For example, aluminum doesn't puff up when it oxidizes. This helps make aluminum oxide a good protective coating, rather than the start of rapid degeneration. Rust is really Fe2O3, a reddish form of iron oxide. Iron has another oxide, Fe3O4, which is sometimes called black oxide, black rust, or hammer scale. Black oxide is a good protection for steel. Like aluminum oxide, black oxide molecules are the same size as iron molecules, so black oxide does not grow or flake. Black oxide is true gun bluing and the oxide found on some drill bits. Black oxide is also seen on iron and steel that has been hot-worked. You can coat steel with black oxide by a careful regimen of rusting the right amount and boiling the rusted metal in water to convert it. This is how non-caustic gun bluing is done, and although it is tedious, it produces very attractive and durable results after several treatments. The iron reacts with the oxtgen The element iron "rusts" when it reacts with oxygen of the air, usually in the presence of water, to form a brown substance known as iron oxide. It is a slow chemical reaction which takes place over a period of time. Rust is the common name for iron oxide. Iron oxide is comes in several forms. The most common are: FeO ---- iron (II) oxide Fe3O4 - iron (II,III) oxide Fe2O3 - iron (III) oxide As to why iron will rust, or put more chemically, why iron will oxidize : Iron oxide has a lower free energy than do iron and oxygen. Just as a ball will roll downhill because it has a lower free energy at the bottom of the hill than at the top, iron will combine with oxygen - essentially 'rolling down a chemical reaction hill'. The reason things like water, salt, acids and other chemicals cause iron to rust faster, is that these substances act as catalysts to the oxidation reaction. Practically all metals oxidize just like iron; however, usually this layer of oxide on the surface protects the rest of the metal. Aluminum objects, for example, all have a thin layer of Aluminum Oxide on the surface, protecting the rest of the metal from oxidation. With iron, the oxide layer happens to flake off or "exfoliate". This exposes new metal under the oxide layer and so it doesn't protect the metal like oxide layers do on other metals. So, iron doesn't rust because it oxidizes more easily than other metals. Aluminum actually oxidizes more readily than iron. But iron's oxide's layers flake off, so the metal isn't protected by it. We can also say that the addition of water (hydration) is taking place, and as iron is a transition element, it has variable oxidation states. Before adding water, its oxidation state is +2 and after the addition of water it is a +3 state. Oxidation via air and water. Rust is caused by oxidation. If you take a piece of iron and you spray or paint it with a clear plastic then you are stopping the oxygen from getting to it. The result is that it can not rust. Rusting of iron is a chemical process.Iron metals get rust on coming in contact with moist air and get corroded.the chemical reaction is represented as; Fe+O2+H2O--Fe2O3.xH2O iron reacts with oxygen to produce iron oxide known as rust coastal areas are more humid.so there is more moisture in the air.air with many oxygen which makes iron rust fastly.
Asked in Astronomy, Chemistry, Planetary Science
What are the four orbital shapes?
We can come up with only three: -- hyperbolic -- parabolic -- elliptical (including circular, a special case of elliptical) Circles, ellipses, parabolas and hyperbolas are all conic sections, the intersection of a plane with a right-circular cone. Orbitals in quantum chemistry have shapes that are spheres for s-orbitals, dumbbells for p-orbitals, and different types of d-orbital are either pairs of crossed dumbbells, or a dumbbell with a central collar. f-orbitals have yet more complex shapes, but they are not usually considered in textbooks. In physics, p and d orbitals have rather different shapes. A s-orbital is still a sphere, but p-orbitals are either dumbbells or tyres, and d-orbitals are collared dumbbells, double (point to point) cones, or tyres.
Asked in Science, Chemistry, Elements and Compounds
What are some products of combustion?
water, carbon dioxide, carbon monoxide (in incomplete combustion) There's also nitrogen oxides. Really, it depends on what you burn. A sulfur fire, a magnesium fire and a tire fire have radically different combustion products. <<>> when combustion occurs it's sometines useful to separate out the byproducts from the main products. For example, when oil is burnt, the main products are carbon dioxide and water. That means the heat energy comes from atomic bonds formed between the carbon and oxygen, and between the hydrogen and more oxygen. Those are main products, while byproducts are things like carbon monoxide, sulpur componds and nitrous oxides. They are unwanted products which can be removed by filtering the fuel and/or the exhaust gas.
Which bonding holds atoms together in a biological molecule?
What is adiabatic calorimetry?
Adiabatic calorimetry is used primarily for the study of thermal hazards and the consequences of a maloperation during a process, for instance a misfeed or loss of cooling. This is because on larger scales the effective natural cooling rates are negligible in comparison to heat generation, and many large process vessels can therefore be considered to be adiabatic. An adiabatic calorimeter is designed to simulate the thermal behaviour of larger scale chemical reactors, especially when studying uncontrolled and run-away reactions.
Asked in Science, Chemistry, Organic Chemistry
Is graphene stronger than diamonds?
Yes graphene is a new two-dimensional material what is the hardest and thinnest material known to man also it can conduct electricity 100 times faster than silicon in computer chips and much much more it really is a wonder material so yes it is harder than diamond. NB: Natural diamond is the hardest natural mineral known. As well, hard and strong do not necessarily equate.
Asked in Chemistry, Batteries
Can a cucumber fruit extract be able to produce electricity?
Yes. Electricity will be produced wherever two different metals are immersed in an electrolyte. In this case, the fruit or vegetable juice acts as the electrolytic solution that allows ionic motion. Lemons and Potatoes are well known fruits and vegetables that work as a battery and a cucumber has much of the same properties. To ensure the best result, make sure you use a zinc and a copper wire to plug into the cucumber. Other metals will work and you can find lists which give information about which metal are most dissimilar. This is called a galvanic series.
What is intermolecular Force?
Answer: Intermolecular forces are the forces of attraction and repulsion that act between molecules or ions to influence the physical properties of compouds. intermolecular forces are forces that act between stable molecules or between functional groups of macromolecules. Answer: Well the key word is molecule. In a substance like water... There are many water molecules. Water molecules are made up of two hydrogen and one oxygen. When someone says the intermolecular forces they are talking about how each molecules of any substance (in this case "water") interact with each other. Each substance or "thing" that we see has intermolecular forces. Answer: The intermolecular forces means how strong the bonding is between each individual molecule. This strength of the bonds determines whether a substance is a solid, liquid, or gas at room temperature. Intermolecular forces are the forces of attraction between molecules. They include:- Hydrogen bonding, van der waals forces which includes dipole -dipole interactions, dipole -induced dipole interactions, instantaneous dipole interactions (London dispersion forces) Intermolecular force - or physical force - is the attraction between molecules. It attracts the molecules to stick together or repulses the molecules to separate them.
Asked in Chemistry, Drinking Water, Desalinization
Checking the bacterial contamination in drinking water by testing sulphide ion?
Asked in Chemistry, Elements and Compounds
How many atoms are present in two mole of H2O?
each mole of h2o molecules contains 2 moles of hydrogen atoms and 1 mole of oxygen atoms. Therefore, three moles of atoms make up one mole of hydrogen molecules. And, six moles of atoms make up 2 moles of h2o. There are 6.023E23 atoms in a mole. So, six moles of atoms is equal to 6(6.023E23) or 3.614E24 atoms Wouldn't that be 36.14? More precisely a mole is simply a term that denotes a particular quantity. Just as a dozen equals 12 of something a mole is a specific quantity of atoms a dozen trucks or a dozen cotton balls still equal 12 of each. So to it is with a mole. A mole is 6.0221367 X 10^23, or 6.0221367E23. To put that as a number most people recognize you take 6.0221367 and move the decimal point 23 places to the right. That makes a mole equal to 602,213,670,000,000,000,000,000 which, don't quote me, lol, I believe is in the sextillions. Whatever it is it is an extremely large number! People can sometimes get confused at this next step. Your question asked how many "atoms" are present in 2 mole of H2O. H2O is a molecule, the sum of 2 Hydrogen atoms and 1 oxygen atom. To draw a parallel think of it like this: how many tires are there in 2 dozen vehicles? It takes 4 tires per vehicle and 2 dozen cars are 24. 24 X 4 = 96. Same logic applies here because it requires 3 atoms to make one water molecule. 2 mole of water molecules are simple to equate. It is 6.0221367 X 10^23 multiplied by 2. 3 atoms per molecule so as the original respondent stated there are 4 mole of Hydrogen atoms and 2 mole of Oxygen atoms in 2 mole of water molecules. That number, hold on to your hat, is 3.61328202 X 10^24 or 3,613,282,020,000,000,000,000,000 and I believe that is Three Septillion Six Hundred Thirteen Sextillion Two Hundred Eighty Two Pentillion Twenty Quadrillion. Which is alot, alot, alot, alot, lot, lot, lot, lot, lot!
Asked in Biology, Chemistry, History of Science
What is biological methods?
The scientific method in which biological problems are solved is termed as biological method.It comprises the steps a biologist adopt in order to solve a biological problem,In solving a biological problem a biologist adopt the following steps 1) Recognition of biological problem. 2) Observation. 3) Hypothesis formulation. 4) Deduction. 5) Experimentation. 6) Summarization of result. 7) Reporting of result. 8) Formation of theory. 9) Biological Law