How to Calculate Volume Percent Concentration

How to Calculate Volume Percent Concentration Volume percent or volume/volume percent (v/v%)  is used when preparing solutions of liquids. It is very easy to prepare a chemical solution using volume percent, but if you misunderstand the definition of this unit of concentration, youll experience problems. Percent Volume Definition Volume percent is defined as: v/v % [(volume of solute)/(volume of solution)] x 100% Note that volume percent is relative to volume of solution, not volume of solvent. For example, wine is about 12% v/v ethanol. This means there are 12 ml ethanol for every 100 ml of wine. It is important to realize liquid and gas volumes are not necessarily additive. If you mix 12 ml of ethanol and 100 ml of wine, you will get less than 112 ml of solution. As another example, 70% v/v rubbing alcohol may be prepared by taking 700 ml of isopropyl alcohol and adding sufficient water to obtain 1000 ml of solution (which will not be 300 ml). Solutions made to a specific volume percent concentration typically are prepared using a volumetric flask. When Is Volume Percent Used? Volume percent (vol/vol% or v/v%) should be used whenever a solution is prepared by mixing pure liquid solutions. In particular, its useful where miscibility comes into play, as with volume and alcohol. Acid and base aqueous reagents are usually described using weight percent (w/w%). An example is  concentrated hydrochloric acid, which is 37% HCl w/w. Dilute solutions are often described using weight/volume % (w/v%). An example is 1% sodium dodecyl sulfate.  Although its a good idea to always cite the units used in percentages, it seems common for people to omit them for w/v%. Also, note weight is really mass.

The Saxons Were a Germanic People

The Saxons Were a Germanic People The Saxons were an early Germanic tribe that would play a significant role in both post-Roman Britain and early medieval Europe. From the first few centuries B.C. up until about 800 C.E., the Saxons occupied parts of northern Europe, with many of them settling along the Baltic coast. When the Roman Empire went into its long decline in the third and fourth centuries C.E., Saxon pirates took advantage of the reduced power of the Roman military and navy and made frequent raids along the coasts of the Baltic and the North Sea. Expansion Across Europe In the fifth century C.E., Saxons began to expand fairly rapidly throughout present-day Germany and into present-day France and Britain. Saxon migrants were numerous and dynamic in England, establishing along with several other Germanic tribes settlements and power bases in territory that until recently (c. 410 C.E.) had been under Roman control. Saxons and other Germans displaced many Celtic and Romano-British peoples, who moved westward into Wales or crossed the sea back to France, settling in Brittany. Among the other migrating Germanic peoples were Jutes, Frisians, and Angles; it is the combination of Angle and Saxon that gives us the term Anglo-Saxon for the culture that developed, over the course of a few centuries, in Post-Roman Britain. The Saxons and Charlemagne Not all Saxons left Europe for Britain. Thriving, dynamic Saxon tribes remained in Europe, in Germany in particular, some of them settling in the region that is today known as Saxony. Their steady expansion ultimately brought them into conflict with the Franks, and once Charlemagne became king of the Franks, friction turned to out-and-out war. The Saxons were among the last peoples of Europe to retain their pagan gods, and Charlemagne became determined to convert the Saxons to Christianity by any means necessary. Charlemagnes war with the Saxons lasted 33 years, and in all, he engaged them in battle 18 times. The Frankish king was particularly brutal in these battles, and ultimately, his ordered execution of 4500 prisoners in one day broke the spirit of resistance the Saxons had displayed for decades. The Saxon people were absorbed into the Carolingian empire, and, in Europe, naught but the duchy of Saxony remained of the Saxons.