Chapter 1
Chemistry Project
Zosimos of Panopolis
He describes a series of useful apparatus - for distillation, sublimation, filtration, fixation and others in great detail. Many of the instruments are adapted from cooking utensils or items used in perfumery or other crafts. While he didn't make many of the instruments, he does describe them in great detail. For example, one called the kerotakis- is designed to expose one material to the vapors of another. He seemed especially interested in the action of vapors on solids (based on appliedl observations). He knew that the vapors released by heated cadmia (calamine, a zinc-containing earth) could turn copper golden by transforming it into brass (an alloy of zinc and copper) The vapors of mercury and arsenic whiten copper to a silvery color. Knowledge of these color changes made Zosimos seek similar processes that would bring about true transmutations. Most people think that alchemists worked more or less blindly--just mixing things in a random search for gold, but that's not quite true as with Zosimos we can identify theoretical principles that guided his practical work as well as practical observations that supported or modified his theories. His theories, albeit wrong, were solid and guided his experiments. His observant, active , questioning mind is shown as he noticed the different effects of sulfur vapor in different substances, and expresses his astonishment that while the vapor is and whitens most substances, when is is absorbed by mercury, which is itself white, the resulting composition is yellow. He likewise expresses his surprise that when the vapor of sulfur turns mercury into a solid, not only does the mercury lose its volatility and become fixed, but the sulfur also becomes fixed and remains combined with the mercury. HIs observation is now recognized as a basic principle of chemistry: when substances react with one another, their properties are not “averaged,” as they would be in a mixture, but are instead completely changed. Zosimos was a careful observer who thought deeply about what he witnessed experimentally.
There's not enough known about his experiments and theories to decide what aspects are and aren't based on scientific thinking. We know only descriptions of instruments and observations but no idea of the steps used to in the experiments from him.
Metallic Alloys
Alloys are metallic materials consisting of two or more elements combined in such a way that they cannot be readily separated by physical means that are usually to combine or increase certain characteristics.
Formation of alloys
There are several different ways to make an alloy, the main ones being to make a solid solution, powder metallurgy, and/or ion implantation. To make a solid solution is the traditional way of making alloys by heating the components until they melt into a liquid, and then continue to mix them together and let cool. Powder metallurgy is a technique involving turning the components into powders, and then fusing them with a combination of high pressure and high temperature. Ion implantation involves firing beams of ions into the surface layer of a piece of metal.
Types of Alloys
There are two types of alloys: substitutional alloys and interstitial alloys.
In substitutional alloys, the atoms of the alloying agent replace atoms of the main metal. In interstitial alloys, the alloying agent or agents have atoms that are very much smaller than those of the main metal. In that case, the agent atoms slip in between the main metal atoms. Examples of alloys:
Purity Grades
Technical grade chemicals are less pure (has more impurities) than reagent grade chemicals, and are usually used in applications where there are no official standards for impurity levels. This grade is suitable for non-critical tasks in the laboratory such as rinsing, dissolving, or are used as raw materials.
FCC grade is an internationally recognized standard for purity and identity of food ingredients. The FCC provides an essential criteria and analytical methods to authenticate and determine the quality of food ingredients. Products that are of FCC grade meet the strength specification and maximum impurity limit by the FCC
.
NF grade chemicals meet the requirements to be admitted into the pharmaceutical sector (exceeds requirements of the US National Formulary [bought out and merged with the USP]). USP grade is acceptable for food, drug, or medicinal use: may be used for most laboratory purposes (higher purity than most).
ACS grade is the chemical grade of highest purity that meets or exceeds standards set by the American Chemical Society (ACS).
Laboratory grade is of relatively high quality with exact levels of impurities unknown: usually pure enough for educational applications. Not pure enough to be offered for food, drug, or medicinal use of any kind.
Primary standard reagents are of sufficient purity from which standard solutions of known normalities can be prepared by direct weighing of it and diluting to a defined volume of solution. So pure that its weight is truly representative of the number of moles of substance contained.
Parts of a Chemical Equation
A basic chemical equation consists or 2 or more reactants with a subscript or coefficient separated by plus signs followed by a right arrow with yields (or products) to the right of it (ex. reactant + reactant → yield (product).
Reactants are substances that take part in and undergo changes during a reaction. They are to the right of the yield sign
Products (referred to as yields) are substances that are formed as the result of a chemical reaction. They are to the left of the yield sign.
A + is used to separate one reactant (or to show a reaction between reactants) or product from another.
An → (yield sign) is used to separate the reactants from the products - it is pronounced “yields”
or “produces” when the equation is read.
⇆ denotes a reversible reaction. The reactants become products and the products can become reactants again using the same process
⇋ shows a reversible reaction when the reaction is at equilibrium
(g) indicates that a substance is in a gaseous stat
(s) indicates that the substance in a solid state
(aq) indicates that a substance is dissolved in water - the aq comes from aqueous
↑ is an alternate way of representing a substance in a gaseous state
↓ is an alternate way of representing a substance in a solid state
Coefficients (big numbers to the left of the element) are indicating the relative number of molecules of each kind involved in the reaction
Subscripts (small numbers to the right of an element) indicates the specific number of atoms of the element found in the substance