Avogadro, Amedeo gases

Gay-Lussac measured how the temperature of a gas affects its pressure, volume, and density. The Italian scientist Amedeo Avogadro made a further contribution that established the relation between the volume and the amount of molecules in the sample and thereby helped to establish belief in the reality of atoms. 

After some debate between the two, in which Dalton cast doubt on Gay-Lussac s experiments, the conclusion was reached that equal volumes of gas (when measured under the same conditions of temperature and pressure) must contain equal numbers of molecules. This statement (Avogadro 1811), attributable to another great scientist, Amedeo Avogadro (1776-1856), from 1820 Professor of Physics at Turin, was consistent with observation, if it is assumed that simple gases such as oxygen and nitrogen are composed of molecules made up of two atoms, and is now known as Avogadro s... 

As discussed in Chapter 3, the 19th-century Italian scientist Amedeo Avogadro hypothesized that the volume of a gas is a function of the number of gas particles it contains. In other words, as the number of gas particles increases, so does the volume, assuming a constant pressure and temperature. This relationship is known as Avogadro s Law. An easy way to demonstrate this law is to blow into an empty plastic bag. The more air molecules you blow into the bag, the bigger its volume. Mathematically, we can depict Avogadro s Law by the following equation ... 

A third contribution to our understanding of gases was made by the Italian scientist Amedeo Avogadro, whose work enabled scientists to accept the reality of atoms. The molar volume, VJm of a substance—any substance, not only a gas—is the volume it occupies per mole of molecules, n. Specifically, if V is the volume of a sample and n is the number of moles of molecules the sample contains, the molar volume is... 

While most beginning chemistry students associate the name of Avogadro with moles and Avogadro s number, Amedeo Avogadro s principal contribution to the chemical sciences is the hypothesis that, at equal temperatures and pressures, equal volumes of gas contain equal numbers of particles. This work made the determination of several atomic and molecular masses possible. In other words, the volume of a gas is directly proportional to the number of gas molecules, as long as temperature and pressure are held constant. 

The relationship between the volume of a gas and the quantity of the gaseous material, as represented by the number of moles, was established by Amedeo Avogadro in the early 1800s. He deduced from experiments performed by Joseph-Louis Gay-Lussac that equal volumes of different gases at the same temperature and pressure contained the same number of moles. This idea leads to Avogadro s law, which states that the volume of a gas at constant temperature and pressure is directly proportional to the number of moles of the gas, or... 

We have considered relationships between the pressure, volume and temperature of a gas, but obviously properties also depend on howmuch stuffis present. To account for this properly, we have to step out of the purely thermodynamic context we have been using and introduce the atoms. Amedeo Avogadro proposed that at a given temperature and pressure, equal volumes of gas contain the same number of molecules, or V n. There is an enormous number of molecnles in (say) 1 liter of a gas, so instead of using numbers of molecules, we use moles (the word comes from the Latin, massive heap ). The modem definition is given in the box. 

Finally, Amedeo Avogadro proposed in the 1800s that the number of molecules in a gas was directly proportional to the volume of the gas. This relationship is expressed as... 

What is a mole The mole, commonly abbreviated mol, is the SI base unit used to measure the amount of a substance. It is the number of representative particles, carbon atoms, in exactly 12 g of pure carbon-12. Through years of experimentation, it has been established that a mole of anything contains 6.022 136 7 X 10 representative particles. A representative particle is any kind of particle such as atoms, molecules, formula units, electrons, or ions. The number 6.022 136 7 X 10 is called Avogadro s number in honor of the Italian physicist and lawyer Amedeo Avogadro who, in 1811, determined the volume of one mole of a gas. In this book, Avogadro s number will be rounded to three significant figures—6.02 X 10. ... 

Amedeo Avogadro (1776-1856) proposed the relationship between volume and quantity of gas in 1811, which has stood the test of time Equal volumes of two different gases at the same temperature and pressure contain the same number of molecules. The last phrase same number of molecules can also be stated as same number of moles. An enlargement of this observation has given us the gas law that bears his name. 

The work of the Itahan scientist Amedeo Avogadro complemented the studies of Boyle, Charles, and Gay-Lussac. In 1811 he published a hypothesis stating that at the same temperature and pressure, equal volumes of different gases contain the same number of molecules (or atoms if the gas is monatomic). It follows that the volume of any given gas must be proportional to the number of moles of molecules present that is. 

Cannizzaro was a talented organic chemist and an early leader in the discipline, but it is his contribution to the then-existing debate over atoms, molecules, and atomic weights for which he is best known. He championed Amedeo Avogadro s notion that equal volumes of gas at the same pressure and temperature held equal numbers of molecules or atoms, and the notion that equal volumes of gas could be used to calculate atomic weights. In so doing, Cannizzaro provided a new understanding of chemistry. 

Mendeleev also attended the 1860 Karlsruhe Congress, the first international chemistry conference. Many of the leading chemists of the day were in attendance, and one of the central questions addressed was the appropriate method for calculating atomic weight. Different chemists used different systems, leading to widespread confusion over everything from nomenclature to chemical formulas. Mendeleev heard the Itafian chemist Stanislao Cannizzaro present Amedeo Avogadro s hypothesis that equal vol-tunes of gas under equal temperature and pressure contained equal numbers of molecules. 

The number 6.0221367 x 10 is called Avogadro s number, in honor of the Italian physicist and lawyer Amedeo Avogadro, who, in 1811, determined the volume of 1 mol of a gas. In this book, Avogadro s number is rounded to three significant figures, 6.02 x 10. ... 

Avogadro s Principle In closing, we will discuss Avogadro s principle. Lorenzo Romano Amedeo Carlo Avogadro s contribution to gas theory is the idea that the volume of a gas is a measure of the number of particles it is made up of, independent of the type of the particles. At given temperature and pressure, the volume of a gas is proportional to the amount of substance in question ... 

The relationship between the quantity of a gas and its volume follows from the work of Joseph Louis Gay-Lussac (1778-1823) and Amedeo Avogadro (1776-1856). 

Three years later Amedeo Avogadro interpreted Gay-Lussac s observation by proposing what is now known as Avogadro s hypothesis Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. For example, 22.4 L of any gas at 0 °C and 1 atm contain 6.02 X 10 gas molecules (that is, 1 mol), as depicted inT FIGURE 10.10. 

Amedeo Avogadro (the same Avogadro that gave us his famous number of particles per mole — see Chapter 10) determined, from his study of gases, that equal volumes of gases at the same temperature and pressure contain equal numbers of gas particles. So Avogadro s Law says that the volume of a gas is directly proportional to the number of moles of gas (number of gas particles) at a constant temperature and pressure. Mathematically, Avogadro s Law loote like this ... 

Avogadro s number a-v9- ga-(i)droz- [Count Amedeo Avogadro] (1924) np. The number of atoms in exactly 12g of C ... 

So far, we have learned how V, P, and T are interrelated, but we have considered only a constant amount of a gas. What happens when the amount of gas changes If we make several measurements of the volume of a gas sample (at constant temperature and pressure) while varying the number of moles in the sample, we get results similar to those shown in T Figure 11.18. We can see that the relationship between volume and number of moles is linear. An extrapolation to zero moles shows a zero volume, as we might expect. This relationship was first stated formally by Amedeo Avogadro (1776-18 ) and is called Avogadro s law. 

Amedeo Carlo Avogadro (1776-1856) was an Italian chemist, most noted for his contributions to the theory of molarity and molecular weight. In 1811, he declared the hypothesis of what we now call Avogadro s law Equal volumes of gases, at the same temperature and pressure, contain the same number of molecules. Hence, the gas laws of Boyle, Mariotte and Cay-Lussac in combination with Avogadro s Law can be generalized by the ideal gas law. The Avogadro constant Na, that is, the number of molecules in one mol is 6.022 x 10 mol is named in his honor. The numerical value of /Va was first estimated in 1865 by Johann Josef Loschmidt (1821-1895), an Austrian scientist. 

Shortly after Gay-Lussac s observations became known, the Italian scientist Amedeo Avogadro reasoned that they could be explained if equal volumes of all gases at the same temperature and pressure contain the same number of molecules (Fig. 14.2). If the reacting molecules react in a 1 1 ratio, and the reacting volumes also have a 1 1 ratio, then the equal volumes of the different gases must have the same number of molecules. If both ratios are 1 2, then the larger volume must have twice as many molecules as the smaller volume of the other gas. It follows that Van at constant temperature and pressure. These statements are known as Avogadro s Law (Fig. 14.3). 

Count Amedeo Avogadro (1776-1856), depicted on a 1956 Italian postage stamp. The quote says, Equal volumes of gas in the same conditions of temperature and of pressure contain the same number of molecules. ... 

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