Answer: BaI
{2}
⋅
4
H
{2}
O
any number in {} is small
Explanation: The idea here is that you need to use the number of moles of anhydrous barium iodide, BaI
{2}
, and of water, H {2} O
, to find the mole ratio that exists between the anhydrous salt and its water of hydration in the hydrate.
1.An astrolabe was an instrument which helped sailors to find their location by looking at the stars and sun
2. Crusaders were people who went on the Crusades
3. The feudal system was the social, economic, and political system of Europe in the Middle Ages
4. A manor was a large estate or farm, part of which was set aside for the lord and the rest divided among his peasants
5. The Middle Ages was the period in European history between ancient and modern times, from about A.D. 500 to about 1500
6. A Muslim is a believer in the religion of Islam; a follower of Mohammed
7. A serf was a peasant in the feudal system midway between a freeman and a slave
Plastic is a word that originally meant “pliable and easily shaped.” It only recently became a name for a category of materials called polymers. The word polymer means “of many parts,” and polymers are made of long chains of molecules. Polymers abound in nature. Cellulose, the material that makes up the cell walls of plants, is a very common natural polymer.
Over the last century and a half humans have learned how to make synthetic polymers, sometimes using natural substances like cellulose, but more often using the plentiful carbon atoms provided by petroleum and other fossil fuels. Synthetic polymers are made up of long chains of atoms, arranged in repeating units, often much longer than those found in nature. It is the length of these chains, and the patterns in which they are arrayed, that make polymers strong, lightweight, and flexible. In other words, it’s what makes them so plastic.
These properties make synthetic polymers exceptionally useful, and since we learned how to create and manipulate them, polymers have become an essential part of our lives. Especially over the last 50 years plastics have saturated our world and changed the way that we live.
The First Synthetic Plastic
The first synthetic polymer was invented in 1869 by John Wesley Hyatt, who was inspired by a New York firm’s offer of $10,000 for anyone who could provide a substitute for ivory. The growing popularity of billiards had put a strain on the supply of natural ivory, obtained through the slaughter of wild elephants. By treating cellulose, derived from cotton fiber, with camphor, Hyatt discovered a plastic that could be crafted into a variety of shapes and made to imitate natural substances like tortoiseshell, horn, linen, and ivory.
This discovery was revolutionary. For the first time human manufacturing was not constrained by the limits of nature. Nature only supplied so much wood, metal, stone, bone, tusk, and horn. But now humans could create new materials. This development helped not only people but also the environment. Advertisements praised celluloid as the savior of the elephant and the tortoise. Plastics could protect the natural world from the destructive forces of human need.
The creation of new materials also helped free people from the social and economic constraints imposed by the scarcity of natural resources. Inexpensive celluloid made material wealth more widespread and obtainable.
Answer:
but I don't know what I'd 3
Explanation:
c to get a new one and I will be there for the first time in a
Answer:
Black preachers provided leadership, encouraged education and economic growth, and were often the primary link between the black and white communities. The black church established and/or maintained the first black schools and encouraged community members to fund these schools and other public services.
Explanation:
