As the tannins produce hydrogen peroxide the colour changes and then the peroxide changes the ethanol to ethanal and then on to acetic acid. The colour will change, the smell will be different, the ethanol decreases, the titratable acidity will increase.
It indicates that early humans had an elementary knowledge of chemistry. History of ferrous metallurgy and History of metallurgy in the Indian subcontinent The earliest recorded metal employed by humans seems to be gold which can be found free or "native".
Small amounts of natural gold have been found in Spanish caves used during the late Paleolithic period, c. However, for millennia fire was seen simply as a mystical force that could transform one substance into another burning wood, or boiling water while producing heat and light.
Fire affected many aspects of early societies. These ranged from the simplest facets of everyday life, such as cooking and habitat lighting, to more advanced technologies, such as pottery, bricks, and melting of metals to make tools. It was fire that led to the discovery of glass and the purification of metals which in turn gave way to the rise of metallurgy.
Bronze Age Certain metals can be recovered from their ores by simply heating the rocks in a fire: However, as often happens with the study of prehistoric times, the ultimate beginnings cannot be clearly defined and new discoveries are ongoing.
Mining areas of the ancient Middle East. Yellow area stands for arsenic bronzewhile grey area stands for tin bronze. These first metals were single ones or as found. By combining copper and tin, a superior metal could be made, an alloy called bronzea major technological shift which began the Bronze Age about BC.
The Bronze Age was period in human cultural development when the most advanced metalworking at least in systematic and widespread use included techniques for smelting copper and tin from naturally occurring outcroppings of copper ores, and then smelting those ores to cast bronze.
These naturally occurring ores typically included arsenic as a common impurity. After the Bronze Age, the history of metallurgy was marked by armies seeking better weaponry. Countries in Eurasia prospered when they made the superior alloys, which, in turn, made better armor and better weapons.
Iron Age The extraction of iron from its ore into a workable metal is much more difficult than copper or tin. While iron is not better suited for tools than bronze until steel was discoverediron ore is much more abundant and common than either copper or tin.
So iron was much more often available locally without have to trade for it. The secret of extracting and working iron was a key factor in the success of the Philistines. Historical developments in ferrous metallurgy can be found in a wide variety of past cultures and civilizations.
This includes the ancient and medieval kingdoms and empires of the Middle East and Near East, ancient Iranancient Egyptancient Nubiaand Anatolia TurkeyAncient NokCarthagethe Greeks and Romans of ancient Europe, medieval Europe, ancient and medieval China, ancient and medieval India, ancient and medieval Japan, amongst others.
Many applications, practices, and devices associated or involved in metallurgy were established in ancient China, such as the innovation of the blast furnacecast ironhydraulic -powered trip hammersand double acting piston bellows.
Atomism DemocritusGreek philosopher of atomistic school. Philosophical attempts to rationalize why different substances have different properties color, density, smellexist in different states gaseous, liquid, and solidand react in a different manner when exposed to environments, for example to water or fire or temperature changes, led ancient philosophers to postulate the first theories on nature and chemistry.
The history of such philosophical theories that relate to chemistry can probably be traced back to every single ancient civilization. The common aspect in all these theories was the attempt to identify a small number of primary classical element that make up all the various substances in nature.
The early theory of atomism can be traced back to ancient Greece and ancient India. Leucippus also declared that atoms were the most indivisible part of matter.
This coincided with a similar declaration by Indian philosopher Kanada in his Vaisheshika sutras around the same time period. What Kanada declared by sutra, Democritus declared by philosophical musing. Both suffered from a lack of empirical data. Without scientific proof, the existence of atoms was easy to deny.
Aristotle opposed the existence of atoms in BC.
Earlier, in BC, a Greek text attributed to Polybus argues that the human body is composed of four humours. Around BC, Epicurus postulated a universe of indestructible atoms in which man himself is responsible for achieving a balanced life.Investigating stoichiometry with Sodium Salts of Carbonic Acid Lab Report Experiment 7 Introduction The purpose of this lab is to investigate and better.
Free Essay: Experiment 7 INVESTIGATING STOICHIOMETRY WITH SODIUM SALTS OF CARBONIC ACID Introduction In this experiment we are going to get a better. We have the equation: HCl + NaHCO 3-> NaCl + H 2 O + CO 2 n NaHCO 3 = 84 = ¿ * (mol) n NaCl = ( * ) * 1 1 = * m NaCl = ( * ) * (molar mass NaCl) = ( * ) * (23 + ) = (g) So the theoretical yield of NaCl when g of NaHCO3 reacts with HCl equals to grams.
As already discussed in Chapter 2, plant cell cultures are the potential source for the production of high-value secondary metabolites. The totipotent nature of culturing cells preserves their genetic information and is thus capable of producing a large number of biochemicals found in the parent plant.
Investigating Stoichiometry with Sodium Salt of Carbonic Acid Introduction The Problem that was introduced in this lab is that we as a group were using stoichiometry to react different reactants of either sodium bicarbonate or sodium carbonate and hydrochloric acid to produce sodium chloride and carbon dioxide.
The history of chemistry represents a time span from ancient history to the present. By BC, civilizations used technologies that would eventually form the basis of the various branches of chemistry. Examples include extracting metals from ores, making pottery and glazes, fermenting beer and wine, extracting chemicals from plants for medicine and perfume, rendering fat into soap, making.