Gases and Their Applications - ppt download
Dalton's law of partial pressures states that the total pressure of a gas mixture is the sum of the The critical pressure of carbon dioxide is atm. What is this .. Then, in the mids, a new breed of thinkers known as natural .. In the equation representing the ideal gas law, the constant R is known as the ideal gas . Use Boyle's Law to calculate volume-pressure relationships. Step 3: Think about your result. Mathematically, the direct relationship of Charles's law can be represented by the .. The Haber cycle reaction of gaseous nitrogen and hydrogen to form ammonia is a critical step in the production of fertilizer from ammonia. The empirical evidence presented by Gay-Lussac of gases combining in in order to reduce to two oxides all those which the same metal sometimes presents . the other hand--reasoning from general considerations and his own experiments--that .. According to Boyle's law, the volume of a gas at constant temperature is.
It only makes sense to speak of whole numbers of atoms, so there is no possibility of intermediate mass ratios--at least in compounds that have only one carbon atom. The third edition of Thomson's System of Chemistry [Thomson ] contains a description of Dalton's views.
Gas Laws Boyle’s Law Charle’s law Gay-Lussac’s Law Avogadro’s Law - ppt download
Berthollet included some critical remarks on Dalton's ideas in his introduction to a French edition of Thomson's book. Indeed, the results Gay-Lussac presents support the hypothesis of definite proportions and Dalton's atomic hypothesis.Gay Lussacs Law: Class X ICSE / CBSE : Gas law : Mole Concept
Interestingly, though, Gay-Lussac's attitude in this paragraph seems either neutral or inclined to disbelieve Berthollet's opponents. The early 19th century, however, was still a time of generalists rather than specialists in science. Notes will explain some of the reactions in modern notation and the modern names and formulas of the compounds.
What is important, however, is not so much the identity of the compounds involved in these reactions for indeed, Gay-Lussac did not know the formulas of many of them, and did not report the quantities of product formedbut the fact that in all the reactions the gases combined in simple ratios by volume.
That is to say for example one liter of one reactant with one, two, or three liters of another. Consideration of combining masses led to ratios not nearly as simple. In the first example given, that of water, Gay-Lussac means although does not say so explicitly that water contains parts of hydrogen by volume for every parts of oxygen.
The formula for ammonia is NH3. The reaction between these gases produces a solid salt, " muriate of ammonia" in Gay-Lussac's day, now called ammonium chloride: However, if one slowly adds HBF4 to ammonia, the reaction occurs according to: Thus two distinct reactions take place, one involving equal volumes of ammonia and fluoboric acid, the other requiring twice as much ammonia as fluoboric acid.
The reactions Gay-Lussac reports on only occur between dissolved ammonia and carbon dioxide, as he notes in the next paragraph. When carbon dioxide is dissolved in water, it first forms a compound with formula H2CO3; that substance is what is now called carbonic acid.
The available data Berthollet's concern masses, not volumes. Gay-Lussac, however, is able to convert masses to volumes, because he knows the density of carbon dioxide and ammonia gases. Density or specific gravity is mass divided by volume. Knowledge of any two of density, mass, and volume permits calculation of the third. At any rate, the reactions involving dissolved carbon dioxide are: The first requires equal volumes of ammonia and carbon dioxide; the second requires twice as much ammonia as carbon dioxide.
Note here, however, that Gay-Lussac is willing to note an instance where Berthollet's measurement and his own disagree. So he was not afraid to disagree with Berthollet in print. As a further irony, Berthollet's measurement here is correct!
I think the attitude Gay-Lussac exhibits toward Berthollet and his work is not uncommon in science. Particular measurements or observations seem to be more clear cut than theories or hypotheses; they appear to be more "matters of fact," closer to direct experience. Since their acceptance or rejection requires less judgment, it is easier for one to maintain objectivity about them. In concrete terms, Gay-Lussac has enough objectivity and integrity to disagree openly with Berthollet about the analysis of "muriate of ammonia," even while his respect for Berthollet seems to cloud his judgment concerning definite proportions.
Yet even from the combining masses, a simple relationship is apparent between the two carbonates of ammonia: How could one convince oneself? One possible way, of course, is to try to replicate the experiment. One might also use estimates of the error inherent in Davy's data. Quantitative estimates of error and precision were not often found in chemical analyses published at this time; indeed, statistical methods for the quantitative treatment of error were not yet well developed.
The question "How close is close enough? Here Gay-Lussac presents some additional evidence for the composition of "nitrous gas. Its name until oxymuriatic acidhowever, reflected the belief that it did. It is worth remembering that whatever reagent an analyst used to try to break "oxygenated muriatic acid" into its elements most likely reacted with the already elementary chlorine to form a new compound. Note also that chlorine, like oxygen, is an oxidizer, so a reaction of "oxygenated muriatic acid" could well be confused with a similar reaction of the oxygen it supposedly contains.
We see an example of this in the next footnote present in Gay-Lussac's original: But since the simple ratio of of acid to of oxygen cannot be due to chance, we must conclude that water by combining with dry muriatic acid to form ordinary muriatic acid does not sensibly change its specific gravity. We should be led to the same conclusion from the consideration that the specific gravity of oxygenated muriatic acid, which from our experiments contains no water, is exactly the same as that obtained by adding the density of oxygen gas to three times that of muriatic gas to three times that of muriatic gas, and taking half of this sum.
The fact that gases combine in simple ratios by volume is consistent with Dalton's atomic theory if the number of atoms or molecules in a given volume of different gases was equal or was itself a simple ratio. For example, if the number of molecules in a given volume of nitrogen was the same as that in hydrogen, then the volume ratio of three hydrogens to one nitrogen corresponds to a reaction in which every nitrogen atom combines with three hydrogen atoms.
This turns out to be the case, as is argued in the next chapter. Or it is also plausible, although it turns out not to be true, that a given volume of nitrogen might contain three times as many molecules as the same volume of hydrogen; then the reaction would involve every atom of nitrogen reacting with one atom of hydrogen. Either way, the observation that reactions occur among whole numbers of volumes of gas is consistent with Dalton's idea of reactions taking place among atoms--which by definition come only in whole numbers.
Gay-Lussac mentions in passing that the combining weights of multiple compounds of the same element are simply related as in carbonic acid and carbonic oxide mentioned above. That is, the weights of one element that can combine with a given amount of another element in different compounds of those elements are simple multiples. This is the law of multiple proportions.
This law also follows from Dalton's atomic hypothesis. If compounds are formed by combinations of small numbers of atoms, each of which has a definite weight, then the weight of B in the compound ABn is obviously n times that in the compound AB.
Atoms come only in whole numbers, so n must be a whole number. When the product of a reaction is also gaseous, its volume is also closely related to the volumes of the reactants.
Actually, Gay-Lussac focuses not on the volume of the product but on the "contraction of volume," that is the difference in volume between the product and the combined reactants. In each case the carbon or charcoal is a solid, not a gas, so the comparison is between the first reactant and the product which are both gases. These reported compositions are equivalent to saying that CO2 has 2.
He strays from the focus of the paper so far: These applications amount to testable predictions based on the simplicity of combining volumes. Unfortunately, he does not tell the reader where he is going.
Combination by Volume: Gay-Lussac
The objects of the calculations here are to compute the change in volume of the reaction between oxygen and sulfur to form "sulphurous gas" SO2 and to infer the combining weights of sulfur and oxygen in this compound.
Among the flaws in exposition, he refers to numbers without stating what they represent. In addition, he expresses his numbers to a far greater number of decimal places than the precision of the experimental data warrant. Still, it is worthwhile reconstructing the calculation concerning sulfur-compounds to show just how susceptible chemistry already was to quantitative treatment. The formation of "sulphurous gas" from sulfur and oxygen is not a reaction about which Gay-Lussac has direct information, so he uses information from a variety of related reactions.
He knows that two volumes of "sulphurous gas" combine with one of oxygen to make two of "sulphuric acid" SO3or in modern notation: The weight of sulphuric acid produced for every volume of oxygen that reacts is 2x2. How much of this is oxygen? Here Gay-Lussac uses the quoted result that "sulphuric acid" contains parts oxygen for every parts sulfur, so the oxygen in the sample weighs. Noticing that this is very close to the weight of oxygen in one volume of oxygen gas, Gay-Lussac concludes that one volume of oxygen reacts with solid sulfur to produce one volume of "sulphurous gas.
The law of multiple proportions and the mass ratio in "sulphuric acid" would require I have found, it is true, on heating cinnabar in oxygen gas, that parts of this gas only produce 93 of sulphurous gas. It also appeared as if less sulphurous gas than ammonia gas was necessary to form a neutral salt. But these experiments were not made under suitable conditions--especially the last, which could only be made in presence of water, the sulphurous gas decomposing and precipitating sulphur immediately on being mixed with ammonia gas,--I intend to repeat them and determine exactly all the conditions before drawing any conclusion from them.
This is all the more necessary, as sulphurous gas can be used to analyze sulphuretted hydrogen gasif its proportions are well known. Heating cinnabar in the presence of oxygen causes the sulfur to combine with oxygen. The upshot of Gay-Lussac's footnote is that more careful experiments are needed to determine the density of the sulfur-oxygen compounds.
With more accurate densities, calculations like the ones just made can be used to arrive at the composition of other gases that contain sulfur. The "acids" of phosphorus i. In this paragraph, he suggests a correction to the density of nitrous oxide as reported by Davy. The formation of nitrous oxide from nitrogen and oxygen, Gay-Lussac maintains, involves a contraction by the amount of oxygen added.
Because 2 volumes of N2O contains the mass of 2 volumes of N2 and 1 volume of O2, its density ought to be that of N2 plus half that of O2.
This is another prediction a correct one based on gases combining in simple ratios by volume. The most likely reaction, written in modern notation, is: The volume ratio of nitrous oxide to phosphine PH3 is 4 to 1, not 2.
This provides additional evidence for the relationship between volumes. In modern notation, we would write the reaction: Here the volume of product is the same as that of the reactants, so there is no contraction. Gay-Lussac makes a similar comparison in the next paragraph for the reaction: Here the volume of the product is twice the original volume of nitrogen, but half the total volume of reactants.
Here Gay-Lussac assumes a reaction whose volume proportions are: The coefficient on the product comes from the statement that the apparent contraction of the gases is half the volume of the reactants. Of course, this reaction is incorrect. Nonetheless, the implied relationship among densities is coincidentally correct.
They glow more brightly than other gases when electrons pass through them. Neon is slightly lighter than air, Xenon is quite a bit heavier. Not actually a pure gas, but a gas mixture that acts much like a pure gas. It is used by scuba divers at shallow depthsand to run pneumatic tools, and for producing foam materials.
Laughing gas, Happy gas, Nitro, NOS Once used as an anaesthetic in dentist offices, this sweet-smelling gas reduces pain sensitivity and causes euphoric sensations. It is an excellent oxidizer, reigniting a glowing splint much like oxygen would. Sulfur Hexafluoride One of the densest gases in common use.
Summary 10 Textbook Assignments Read Chapter 1: Know the properties of gases Know the features of some important gases, esp: Oxygen Hydrogen Carbon dioxide Know the environmental problems associated with some gases, eg. The Kinetic Molecular Theory 2. The Kinetic Molecular Theory The Kinetic Theory of Gases tries to explain the similar behaviours of different gases based on the movement of the particles that compose them.
All matter is composed of particles ions, atoms or molecules which are extremely small and have a varying space between them, depending on their state or phase. Particles of matter may attract or repel each other, and the force of attraction or repulsion depends on the distance that separates them.
Particles of matter are always moving. In other words, when it is cold, molecules move slowly and have lower kinetic energy. When the temperature increases, molecules speed up and have more kinetic energy!
In solids, the particles molecules are moving relatively slowly. They have low kinetic energy In liquids, molecules move faster.
They have higher kinetic energy. In gases, the particles move fastest, and have high kinetic energy. But, as we will find out later: Heavy particles moving slowly can have the same kinetic energy as light particles moving faster.
Gas Particles move freely through container. The wide spacing means molecular attraction is negligible. Strong molecular attractions keep them in place. As they capture new electrons, the atoms emit light—they glow.
Gases and Their Applications
Four of these are listed on page 61 of your textbook The fifth one is not. The particles of an ideal gas are in constant motion, and move in straight lines until they collide with other particles The particles of an ideal gas do not exert any attraction or repulsion on each other. The average kinetic energy of the particles is proportional to the absolute temperature. Collisions between particles are perfectly elastic, ie.
No energy is lost in collisions. At absolute zero an ideal gas would occupy no space at all. Not all molecules move at exactly the same speed. The kinetic theory is based on averages of a great many molecules. Even if the molecules are identical and at a uniform temperature, a FEW will be faster than the average, and a FEW will be slower. That means SOME heavy molecules may be moving as fast as the slowest of the light ones.
Temperature is based on the average mean kinetic energy of sextillions of individual molecules. Not the velocity of individual molecules Not the mass of individual molecules. At that speed an oxygen molecule could travel from Montreal to Vancouver in three hours…If it travelled in a straight line. Each air molecule has about ten billion collisions per second 10 billion collisions every second means they bounce around a lot!
The number of oxygen molecules in a classroom is about: The average distance air molecules travel between collisions is about 60nm. Because the distances between particles in a gas is relatively large, gases can be squeezed into a smaller volume. Compressibility makes it possible to store large amounts of a gas compressed into small tanks 2. Gases will expand to fill any container they occupy, due to the random motion of the molecules 34 2. They do this because of the random motion of the molecules.