AC-HPAT Chemistry Study Guide QUESTIONS WITH COMPLETE VERIFIED SOLUTIONS 2024/2025, Study Guides, Projects, Research of Chemistry

Download AC-HPAT Chemistry Study Guide QUESTIONS WITH COMPLETE VERIFIED SOLUTIONS 2024/2025 and more Study Guides, Projects, Research Chemistry in PDF only on Docsity! AC-HPAT Chemistry Study Guide QUESTIONS WITH COMPLETE VERIFIED SOLUTIONS 2024/2025 double-displacement reaction A double displacement reaction, also known as a double replacement reaction or metathesis, is a type of chemical reaction where two compounds react, and the positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products Precipitate precipitate is an insoluble solid that emerges from a liquid solution. The emergence of the insoluble solid from solution is called precipitation. Often the precipitate emerges as a suspension. Precipitates can form when two soluble salts react in solution to form one or more insoluble products. Energy Levels Energy levels (also called electron shells) are fixed distances from the nucleus of an atom where electrons may be found. As you go farther from the nucleus, electrons at higher energy levels have more energy. Electrons in the outermost energy level of an atom are called valence electrons Marquis Test The Marquis Test is commonly used for Ecstasy testing as MDMA turns the precipitate purple black. Cobalt thiocyanate is used to test for cocaine. The Cobalt is mixed with the questionable substance, then drowned in hydrochloric acid, doused in chloroform, and shaken. What is the relation between an atomic number and a mass number? Atomic number is actually the number of protons in an atom while mass number is the number of nucleons i. e, number of protons plus the number of neutrons. Isotopes Isotopes refer to the nuclides of a certain element that have different numbers of neutrons, or in other words, atomic nuclei that have the same number of protons but different numbers of neutrons. A radioisotope is an isotope that is unstable and therefore undergoes radioactive decay or will at some point. Chemical Synthesis Chemical synthesis, the construction of complex chemical compounds from simpler ones. It is the process by which many substances important to daily life are obtained. It is applied to all types of chemical compounds, but most syntheses are of organic molecules. Decomposition A decomposition reaction is a type of chemical reaction in which a single compound breaks down into two or more elements or new compounds. These reactions often involve an energy source such as heat, light, or electricity that breaks apart the bonds of compounds single-displacement reaction A single-displacement reaction, also known as a single-replacement reaction, is a type of chemical reaction where an element reacts with a compound and takes the place of another element in that compound. This type of reaction is typically pictured like this: Here, A replaces B in the compound BC Flame test flame test is an analytical procedure used in chemistry to detect the presence of certain elements, primarily metal ions, based on each element's characteristic emission spectrum. The color of flames in general also depends on temperature; see flame color. Precipitation reaction A precipitation reaction refers to the formation of an insoluble salt when two solutions containing soluble salts are combined. The insoluble salt that falls out of solution is known as the precipitate, hence the reaction's name. Precipitation reactions can help determine the presence of various ions in solution. organic compounds An organic compound is a substance that is added to a product, like food, to improve some qualities such as taste, smell, colour and texture. These substances can be both positive and negative for human health. Synthetic materials Synthetic materials which are by-products of petroleum are non-biodegradable, synthetic products take a long time to decompose, creating long-term pollution. Nylon is hard to recycle, making them hard to decompose, accumulate landfills more. Polyesters are easy to recycle, which makes them less harmful to the society. Electronegativity Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. The Pauling scale is the most commonly used. Fluorine (the most electronegative element) is assigned a value of 4.0, and values range down to caesium and francium which are the least electronegative at 0.7. Covalent bonds Covalent bonds are chemical bonds between two non-metal atoms. An example is water, where hydrogen (H) and oxygen (O) bond together to make (H2O). A full outer shell usually has eight electrons, or two in the case of hydrogen or helium. ... Covalent bonds are formed by atoms sharing valence electrons. Functional Group Plating is an oxidation-reduction reaction, where one material gives up electrons (gets oxidized) and the other material gains electrons (gets reduced). The anode is the electrode at which oxidation occurs, and the cathode is the electrode at which reduction occurs. Oxidation-reduction (redox) reactions are important because they are the principal sources of energy on this planet, both natural or biological and artificial. Oxidation of molecules by removal of hydrogen or combination with oxygen normally liberates large quantities of energy. Rust proofing Rustproofing is the prevention or delay of rusting of iron and steel objects, or the permanent protection against corrosion. Typically, the protection is achieved by a process of surface finishing or treatment. When the oil spray contacts the surface of your car it lifts off any amount of moisture that might be clinging to it. As thin as water itself, the oil can reach into every little seam and spot weld on your vehicle cathodic protection Cathodic protection (CP) is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. A simple method of protection connects the metal to be protected to a more easily corroded "sacrificial metal" to act as the anode. Galvination Galvanization or galvanizing (also spelled galvanisation or galvanising) is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanizing, in which the parts are submerged in a bath of molten hot zinc. Why do metal orthodontic braces not corrode? Because orthodontic wires are positioned close to the oral mucosa for lengthy periods, they should be resistant to corrosion and prevent the release of ions in the oral cavity, and should not cause allergic reactions. In other words, orthodontic wires must be biocompatible with oral tissues. Oxidation Oxidation is any chemical reaction that involves the moving of electrons. ... When iron reacts with oxygen it forms a chemical called rust because it has been oxidized (the iron has lost some electrons) and the oxygen has been reduced (the oxygen has gained some electrons). Anode vs Cathode The anode of a device is the terminal where current flows in from outside. The cathode of a device is the terminal where current flows out. ... By current we mean the positive conventional current. Since electrons are negatively charged, positive current flowing in is the same as electrons flowing out. Electrolyte An electrolyte is a substance that produces an electrically conducting solution when dissolved in a polar solvent, such as water. The dissolved electrolyte separates into cations and anions, which disperse uniformly through the solvent. Galvanic Corrosion Galvanic corrosion occurs when two different metals are in contact in a corrosive environment: one of the metals experiences an accelerated corrosion rate. The contacting metals form a bimetallic couple because of their different affinities (or attraction) for electrons. reduction Reduction is a chemical reaction that involves the gaining of electrons by one of the atoms involved in the reaction between two chemicals. The term refers to the element that accepts electrons, as the oxidation state of the element that gains electrons is lowered. oxidation redox reaction An oxidation-reduction (redox) reaction is a type of chemical reaction that involves a transfer of electrons between two species. An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion change by gaining or losing an electron. Parts of Galvanic Cells 1. The anode is an electrode where oxidation occurs. 2. The cathode is an electrode where reduction occurs. 3. A salt bridge is a chamber of electrolytes necessary to complete the circuit in a voltaic cell. 4. The oxidation and reduction reactions are separated into compartments called half-cells. 5. The external circuit is used to conduct the flow of electrons between the electrodes of the voltaic cell and usually includes a load. 6. The load is the part of the circuit which utilizes the flow of electrons to perform some function. Molar Mass - In chemistry, the molar mass of a chemical compound is defined as the mass of a sample of that compound divided by the amount of substance in that sample, measured in moles - The molar mass is the mass of a given chemical element or chemical compound (g) divided by the amount of substance (mol). The molar mass of a compound can be calculated by adding the standard atomic masses (in g/mol) of the constituent atoms. Molar concentration Molar concentration (also called molarity, amount concentration or substance concentration) is a measure of the concentration of a chemical species, in particular of a solute in a solution, in terms of amount of substance per unit volume of solution Percent yield Percent yield is the percent ratio of actual yield to the theoretical yield. It is calculated to be the experimental yield divided by theoretical yield multiplied by 100%. It's possible for percent yield to be over 100%, which means more sample was recovered from a reaction than predicted Avogadro's number Avogadro's number: the number 6.022 × 1023 indicating the number of atoms or molecules in a mole of any substance. — called also Avogadro number. Mole The Mole. The identity of a substance is defined not only by the types of atoms or ions it contains, but by the quantity of each type of atom or ion. For example, water, H2O, and hydrogen peroxide, H2O2, are alike in that their respective molecules are composed of hydrogen and oxygen atoms. Theoretical vs actual yields Amounts of products calculated from the complete reaction of the limiting reagent are called theoretical yields, whereas the amount actually produced of a product is the actual yield. The ratio of actual yield to theoretical yield expressed in percentage is called the percentage yield molar concentration Molar concentration (also called molarity, amount concentration or substance concentration) is a measure of the concentration of a chemical species, in particular of a solute in a solution, in terms of amount of substance per unit volume of solution. Limiting reagent The limiting reagent (or limiting reactant or limiting agent) in a chemical reaction is the substance that is totally consumed when the chemical reaction is completed. The amount of product formed is limited by this reagent, since the reaction cannot continue without it. aspirin Aspirin can be made by reacting salicylic acid with acetic acid in the presence of an acid catalyst. The phenol group on the salicylic acid forms an ester with the carboxyl group on the acetic acid. However, this reaction is slow and has a relatively low yield Ammonia Ammonia is industrially prepared by the Haber process, a chemical method that uses nitrogen gas and hydrogen gas to synthesize ammonia. One nitrogen gas molecule reacts with three hydrogen gas molecules over finely divided iron as a catalyst to produce two ammonia molecules. Ozone layer Ozone Layer is a layer of the earth's upper atmosphere that is characterized by high ozone content which blocks most of the sun's ultraviolet radiation from entering the lower atmosphere Titration Titration is the slow addition of one solution of a known concentration (called a titrant) to a known volume of another solution of unknown concentration until the reaction reaches neutralization, which is often indicated by a color change. pH pH is a measure of hydrogen ion concentration, a measure of the acidity or alkalinity of a solution. The pH scale usually ranges from 0 to 14. Aqueous solutions at 25°C with a pH less than 7 are acidic, while those with a pH greater than 7 are basic or alkaline. What does ppm mean?