Concept map The heat that flows across the boundaries of a system undergoing a change is a fundamental property that characterizes the process. It is easily measured, and if the process is a chemical reaction carried out at constant pressure, it can also be predicted from the difference between the enthalpies of the products and reactants. The quantitative study and measurement of heat and enthalpy changes is known as thermochemistry. In order to define the thermochemical properties of a process, it is first necessary to write a thermochemical equation that defines the actual change taking place, both in terms of the formulas of the substances involved and their physical states temperature, pressure, and whether solid, liquid, or gaseous.
Chemical Reactions Photo by: It involves making and breaking chemical bonds and the rearrangement of atoms. Chemical reactions are represented by balanced chemical equations, with chemical formulas symbolizing reactants and products.
For specific chemical reactants, two questions may be posed about a possible chemical reaction. First, will a reaction occur? Second, what are the possible products if a reaction occurs? This Sulfur reacting to heat. The most reliable answer is obtained by conducting an experiment—mixing the reactants and then isolating and identifying the products.
We can also use periodicity, since elements within the same group in the Periodic Table undergo similar reactions.
Finally, we can use rules to help predict the products of reactions, based on the classification of inorganic chemical reactions into four general categories: Reactions may also be classified according to whether the oxidation number of one or more elements changes.
Those reactions in which a change in oxidation number occurs are called oxidation—reduction reactions. One element increases its oxidation number is oxidizedwhile the other decreases its oxidation number is reduced.
Combination Reactions In combination reactions, two substances, either elements or compounds, react to produce a single compound. One type of combination reaction involves two elements. Most metals react with most nonmetals to form ionic compounds. The products can be predicted from the charges expected for cations of the metal and anions of the nonmetal.
For example, the product of the reaction between aluminum and bromine can be predicted from the following charges: Since there is a change in the oxidation numbers of the elements, this type of reaction is an oxidation—reduction reaction: The composition of the product is predicted from the common oxidation numbers of the elements, positive for the less reactive and negative for the more reactive nonmetal usually located closer to the upper right side of the Periodic Table.
For example, sulfur reacts with oxygen gas to form gaseous sulfur dioxide: Carbon monoxide, formed by the burning of hydrocarbons under conditions of oxygen deficiency, reacts with oxygen to form carbon dioxide: Two compounds may react to form a new compound.
For example, calcium oxide or lime reacts with carbon dioxide to form calcium carbonate limestone: The products of a decomposition reaction are determined largely by the identity of the anion in the compound.
The ammonium ion also has characteristic decomposition reactions.The full chemical equation is: CaSO4 + 2HCl --> H2SO4 + CaCl2. This states that calcium sulfate plus hydrochloric acid becomes sulfuric acid and calcium chloride. Write balanced molecular, complete ionic, and net ionic equations for each of the following reactions.
Assume all reactions occur in aqueous solution. In chemistry, an ester is a chemical compound derived from an acid (organic or inorganic) in which at least one –OH (hydroxyl) group is replaced by an –O–alkyl group.
Usually, esters are derived from a carboxylic acid and an alcohol. Glycerides, which are fatty acid esters of glycerol, are important esters in biology, being one of the main classes of lipids, and making up the bulk of. The equivalence point of the neutralisation titration is the point at which the moles of H + is equal to the moles of OH-.
An indicator is used to indicate the equivalence point during a titration by changing colour 2.; The titration experiment is usually conducted several times carefully and the volume of solution used from the burette (buret) recorded (known as a titre).
Unit VI Molarity.
Lesson Day Date Topic. 1. Molarity 1 2. Molarity Lab Molarity 2. Microchip Fabrication 5th Ed. by Peter Van Zant Copy - Free ebook download as PDF File .pdf), Text File .txt) or read book online for free.