A-Stage Chemistry Glossary | The Chemistry Weblog
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To reach your chemistry research, you’ll must have a great grasp of the important thing ideas and ideas. That’s why we’ve created this useful glossary of chemical phrases utilized in A-level chemistry.
We’re consistently including extra definitions to our chemistry glossary so you should definitely go to this web page often. And when you’re in search of extra assist and data, don’t neglect to check out our chemistry schooling sources.
Glossary of chemical phrases for A stage college students
Acid
A substance with a pH stage of lower than 7. Based on the Bronsted-Lowry definition, an acid is a proton donor. This implies it readily loses its hydrogen in a neutralisation response with a base. The hydrogen can also be simply changed by a steel, inflicting it to be launched as fuel.
Acid-base buffers
Options that may resist small pH modifications in a system. Acid-base buffers are necessary for a lot of organic methods, together with human blood. Additionally they have quite a lot of industrial purposes and are generally used to fabricate meals and medical gadgets. Sometimes, these buffers include an acid and its conjugate base.
Accuracy
The diploma to which a measurement is closest to the precise worth being measured. For instance, if the temperature of ice is zero levels Celsius and a thermometer signifies the identical, the measurement is alleged to be correct. For measurements to be correct, devices have to be calibrated and there have to be settlement amongst a number of devices measuring the identical parameter.
Alkali metals
The weather within the first column of the periodic desk. Alkali metals type alkaline or base substances comparable to sodium hydroxide once they react with water. Their response with water is extraordinarily exothermic (generates warmth) as hydrogen is launched.
Avogadro’s quantity
The variety of unit particles in a mole of any substance. It’s experimentally decided to be 6.02 x 1023. The time period is known as in honour of the Italian rely and scientist, Lorenzo Romano Amedeo Carlo Avogadro.
Base
A substance (sometimes an aqueous answer) that has a pH worth above 7. Based on the Bronsted-Lowry definition, a base is a proton acceptor. Which means that throughout a neutralisation response, it strips away the hydrogen proton from the acid to type water. Very like an acid, a powerful and concentrated base is corrosive as a result of it might break molecular bonds.
Baeyer reagent
A kind of reagent that’s ready by diluting and cooling a potassium permanganate answer. It’s generally used for the oxidation of alkenes and alkynes.
Becquerel
The SI unit for measuring radioactivity. Named after the French Nobel laureate for physics, Antoine Henri Becquerel, one unit is equal to at least one radioactive decay per second.
Balanced equation
A written illustration of the chemical or ionic reactions utilizing the symbols of the weather and their corresponding subscript numbers. It’s separated by an arrow to indicate the completely different sides of the response. In a balanced equation, there are equal numbers of atoms or charged ions on both aspect of the equation.
Benzyne
A comparatively unstable intermediate chemical species that’s composed of a benzene ring with an adjoining chemical bond. It’s created when the sp2 orbitals overlap on the adjoining carbon atoms of benzene.
Cadmium
A transition steel component with the atomic quantity 48 and the image Cd. Cadmium is among the most necessary transition metals attributable to its wide selection of purposes. In addition to being a part in batteries and solar energy cells, it’s utilized in nuclear reactors to soak up neutrons. Cadmium can also be used to fabricate plastics and pigments.
Calibration
The method of adjusting and evaluating devices to make sure they supply correct and exact measurements. This significant step entails evaluating the readings or outputs of an instrument primarily based on sure requirements of measurement.
Calorie
One of the vital widespread and acquainted items of measuring thermal power. A calorie is the warmth power wanted to extend the temperature of a gram of pure water by one diploma Celsius beneath normal circumstances. One calorie is equal to 4.184 joules.
Candela
The SI unit for measuring gentle depth. A candela is outlined because the luminosity of a monochromatic spherical supply of 540 nm gentle with the equal radiant power of 1/683 watts per steradian.
Carbohydrates
Chain natural compounds which have subunits of sugar. Composed of carbon, hydrogen, and oxygen, carbohydrates could be seen merely as hydrated carbon. The overall formulation for carbohydrates is Cm(H2O)n. As carbohydrates are primarily the product of the photosynthesis of autotrophs, they are often saved in varied varieties comparable to root crops and grains.
Dalton’s Regulation
A fuel regulation that states the overall stress of a fuel combination is the same as the partial pressures of the gases that the combination is made up of once they’re added collectively.
Decantation
A easy technique of separating mixtures both in a laboratory or an industrial setting. Throughout decantation, small particulate matter is separated from the liquid by which it’s suspended. The solids settle on the backside, and the particulate-free high layer of liquid could be extracted.
Decarboxylation
A kind of chemical response by which carbon dioxide is faraway from a substrate. A carboxyl group is faraway from a carbon chain, which then releases carbon dioxide. Decarboxylation performs an necessary function in biology as a result of it converts amino acids into amines and carboxylic acid into ketones.
Dehydration response
A chemical response by which water molecules are faraway from a reactant. When water molecules are faraway from sure kinds of monomers, the monomers type covalent bonds that result in polymerization.
Deionisation
The removing of ions from an answer (often water). Deionization is among the key levels of water purification. Water passes by a sequence of ion alternate columns, which take away the dissolved salts and minerals. Deionized water is often utilized in laboratories and the pharmaceutical trade to arrange varied mixtures and chemical compounds.
Effusion
When fuel diffuses into one other gaseous area or a vacuum by passing by a porous medium or capillaries. This course of is necessary in lots of industrial and chemical processes, comparable to within the separation of uranium isotopes.
Elastomer
A kind of polymer materials that’s stretchy and compressible. When the tensile drive or compressive drive is eliminated, an elastomer returns to its unique form. Rubber is an instance of an elastomer.
Electrochemical cell
A tool that generates electrical energy by an oxidation-reduction response. The response happens when the 2 electrodes – the anode and cathode (two completely different metals) – are immersed in an electrolyte answer. A sequence of electrochemical cells could be related to type a battery of a specific voltage and electrical capability.
Electrochemistry
The scientific research of how various kinds of electrolyte options, chemical reactions, and electrodes could be mixed to provide {an electrical} present or retailer electrical power.
Electron affinity
A measure of the change in power when an electron is added to atoms in a gaseous state. Each atom can settle for electrons at various levels – the stronger the attraction, the extra power is launched.
Household
A gaggle of compounds or parts which have comparable properties. For instance, methane, ethane, and propane belong to the household of hydrocarbons often called alkanes. ‘Household’ can also be used to confer with parts within the periodic desk which have the identical variety of valence electrons.
First regulation of thermodynamics
The idea that power is neither created nor destroyed however merely reworked from one type to a different. It’s often known as the regulation of conservation of power. For instance, the chemical power in petrol vehicles is reworked into warmth power. The warmth power then creates stress that strikes the pistons, reworking it into mechanical power.
Fractional distillation
A separation approach that depends on the completely different boiling factors of the varied elements of a liquid. Fractional distillation is often used on an industrial scale, comparable to within the oil and fuel trade when refining crude oil into various kinds of fuels.
Homosexual-Lussac’s regulation
A model of the perfect fuel regulation that establishes the connection between the stress of the fuel and absolutely the temperature in Kelvin. It states that if the amount is fixed, the stress of an excellent fuel is immediately proportional to its absolute temperature.
Gibbs free power
A measure of the utmost work achieved by a system that’s reversible given fixed stress and temperature.
Gravimetric evaluation
A set of analytical strategies primarily based on inspecting the mass and density of pattern substances, reactants, and merchandise. One well-known instance of gravimetric evaluation is Archimedes’ ‘Eureka’ second. Based on legend, Archimedes decided that the King’s crown wasn’t product of pure gold due to the distinction within the displaced water.
Haber course of
An industrial course of that’s used to provide ammonia by the response between nitrogen and hydrogen fuel. The approach, which is essential to fertiliser manufacturing, entails using a steel catalyst beneath excessive temperatures and pressures.
Heisenberg uncertainty precept
The precept that it’s unattainable to concurrently measure the place and momentum or velocity of a particle with 100% accuracy. It was named after the German theoretical physicist, Werner Heisenberg.
Hydronium ion
The positively-charged ion or cation that’s represented by the image H3O+ in an aqueous answer.
Ideally suited fuel regulation
A mix of Charles’ regulation and Boyle’s regulation that summarises the connection between quantity, stress and temperature. It may be written as an equation:
PV = nRT
The place:
- P – stress
- V – quantity
- n – variety of moles
- R – splendid fuel fixed
- T – temperature
Impartial variable
The variable in an experiment that determines the result of the dependent variables. The unbiased variable is tweaked to see its diploma of impact on the dependent variable. For instance, in a fuel experiment, you possibly can tweak the temperature or stress after which observe the impact on the opposite variable. If all the variables are held fixed, a rise in temperature leads to a rise in stress and vice versa.
Joule
An SI unit used for measuring power. Named after the English physicist, James Prescott Joule, it’s the equal of the work achieved utilizing one Newton of drive transferring a distance of 1 metre.
Kelvin temperature scale
A technique of measuring temperature primarily based on the Celsius scale, however recalibrating for absolute zero temperature. Zero levels Celsius, which is the freezing level of water, is outlined as 273.15 Okay. Which means that absolute zero temperature is -273.15 °C. That is the theoretical temperature at which all particle actions stop because the power of the system reaches zero.
Regulation of chemical equilibrium
Chemical reactants and merchandise are mentioned to be in equilibrium once they’re utterly balanced and the speed of each ahead and backward reactions is equal. Chemical equilibrium specifies the focus of each the reactants and the merchandise. Their stoichiometric coefficients are fixed supplied different elements stay fixed.
Mole
An SI unit used to measure massive portions of very small particles or constituents of a substance. It’s the unit equal of a specific mounted amount of a substance, often in grams. A mole of any substance is all the time equal to Avogadro’s quantity, which is 6.02214076 × 1023.
Molar mass
The mass in grams of 1 mole of a substance. Molar mass is calculated primarily based on the mass of the person constituents of the basic unit of a substance. For instance, the molar mass of water is calculated by figuring out the atomic mass of hydrogen and oxygen. The atomic mass of every component is multiplied by its coefficients after which added collectively. Which means that the molar mass of water is eighteen g/mol.
Neutralisation
The response between an acid and a base. It’s referred to as neutralisation as a result of the ensuing merchandise have a impartial pH of seven. Usually, one of these response produces salts and water.
Octet rule
The precept that the outermost shell of an atom have to be full of eight electrons for it to be full. This rule applies to atomic bonding.
Periodic regulation
A regulation developed by the Russian scientist, Dmitri Mendeleev, that states the chemical properties of the weather have predictable patterns once they’re organized so as of accelerating atomic mass in a periodic desk. This regulation helped Mendeleev predict the gaps within the periodic desk.
Quantitative evaluation
A exact kind of scientific evaluation that goals to measure the share or proportion of elements in a pattern. It makes use of superior statistical strategies, comparable to correlation and regression. Quantitative evaluation differs from qualitative evaluation, which as an alternative focuses on the visible traits of a chemical response.
Reverse osmosis
A water purification course of by which stress is utilized on one aspect of a semi-permeable membrane to drive the move of water from a excessive focus of solute to a low focus of solute. Reverse osmosis is efficient in eradicating microorganisms and mineral impurities from water, together with salt.
Saturated hydrocarbons
Saturated hydrocarbons have single bonds between their carbon atoms. Hydrocarbon chains are mentioned to be saturated when the utmost variety of hydrogen atoms are hooked up to the carbon atoms.
Thermodynamics
The scientific research of how power, associated mechanical methods, and chemical methods work and work together. Vitality and its tendency to turn into much less helpful is among the key ideas tackled by thermodynamics.
UN ID
A regular, internationally-recognised four-digit code that’s used to determine and classify hazardous chemical compounds. UN ID stands for United Nations Identifier.
Valence electron
The electrons situated on the outermost power shell of an atom. Valence electrons are the almost certainly to take part in chemical reactions by forming bonds comparable to ionic and covalent bonds.
Weak acid or weak base
Each a weak acid and a weak base have ions that partially dissociate in aqueous options. This implies the acid or base will not be utterly consumed in a response. They could need to undergo a number of steps earlier than they obtain a stage of dynamic equilibrium.
Xenon
One of many seven noble gases that make up group 18 of the periodic desk. It has the atomic quantity 54 and an atomic weight of 131.29. Xenon doesn’t readily react with different parts or compounds, which is among the the reason why it’s generally utilized in cathode ray tubes.
Yield
The amount of merchandise produced by a chemical response. This may occasionally depend upon the quantity of the reactants and their respective stoichiometry. In chemistry, yield can confer with experimental yield or the precise yield. It could additionally confer with the theoretical yield and proportion yield.
Zaitsev rule
A rule utilized in natural chemistry to foretell the formation of alkenes in elimination reactions. The Zaitsev rule states that elimination reactions will produce alkenes which might be extremely substituted. The one with essentially the most variety of alkyl teams which might be hooked up to the double-bonded carbons is the extremely substituted alkene.
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