Balance febr3 h2so4 fe2 so4 3 hbr

CHEM 102: LECTURE 3 The Chemical Revolution of Lavoisier https://upload.wikimedia.org/wikipedia/commons/1/17/Laboratoire-de-Lavoisier.jpg Lavoisier's Laboratory, Musée des Arts et Métiers, Paris Antoine-Laurent Lavoisier (1734 – 1794) forever changed the practice and concepts of chemistry by forging a new series of laboratory analyses that would bring order to the chaotic centuries of Greek philosophy and medieval alchemy. Lavoisier’s experimental work which led to his discovering the Law of Conservation of Mass and framing the principles of modern chemistry in his Traité élémentaire de chimie (the first Chemistry book) prompted future generations to regard him as a founder of the science. It is generally accepted that Lavoisier's great accomplishments in chemistry stem largely from his changing the science from a qualitative to a quantitative one. Lavoisier is most noted for his discovery of the role oxygen plays in combustion. He recognized and named oxygen (1778) and hydrogen (1783), and opposed an earlier (phlogiston) theory of spontaneous chemical reactions. Lavoisier helped construct the metric system, wrote the first extensive list of elements and helped to reform chemical nomenclature. He predicted the existence of silicon (1787) and was also the first to establish that sulfur was an element (1777) rather than a compound. He discovered that, although matter may change its form or shape, its mass always remains the same. The fossil fuel, natural gas (CH4), “burns” in the presence of oxygen. This is called a combustion reaction or simply oxidation. The Law of Conservation of Mass states that Matter can neither be created or destroyed…. but it can be transformed. If you count the number of carbon atoms (black), the number of hydrogen atoms (white) and the number of oxygen atoms (red) on both sides of the chemical reaction below, they are (respectively) the same. This is made definite in the equation which follows by the integers [1 before methane (CH4), 2 before oxygen (O2), 1 before carbon dioxide (CO2) and 2 before water (H2O)]. upload.wikimedia.org/wikipedia/commons/7/7c/Com... Lavoisier’s experiments were carried out using samples of materials that could be weighed; one describes the samples as “macroscopic.” When the discussion center on atoms, the descriptor is “microscopic.” A macroscopic quantity of matter, say a glass of water, has ~ 6 x 10^23 molecules of water. Think of how big a number this is. The bill passed by Congress to ease the economic concerns caused by coronavirus pandemic is 2 trillion dollars, which is 2 x 10^9 , 14 powers of 10 smaller! If you had Chemistry in High School, the specification of the integers [1,2,1,2] was called “balancing the chemical equation.” What you were really being asked to do was to assume that a law deduced from experiments done on a macroscopic scale can be applied to a problem on the microscopic scale of atoms and molecules. That you were able to do so is a profound statement of the universality of a physical law of Nature. This lecture has two objectives. The first is to review the background of ideas that led to Lavoisier’s discovery of the Law of Conservation of Mass. This journey will reveal other Conservation Laws of Nature, statements that are valid not only at the scale of atoms and molecules, but at the scale of everyday macroscopic experiments, and to events/processes on the scale of the Universe. That is why you need to be familiar with these Laws. They apply at every length scale of the Universe, which is why they are called “universal.” The second objective is to bring you “face to face” with Lavoisier by having you read the description “in his own words” of his discovery of the Law of Conservation of Mass, as described his seminal text, Traité élémentaire de chimie, published in 1789. The Classical Theory of Chemistry. 1. Ideas from the Ancient World a) Thales of Miletus (we know he lived around May 28, 585 BC) Thales proposed that there exists ONE (“chemical”) element in Nature. Further, he proposed that that one element, the primary stuff of all things, is water.

F.Copleston, “A History of Philosophy” vol.1, part 1. “… the phenomena of evaporation suggests that water may become mist or air, while the phenomena of freezing might suggest that, if the process were carried further, water could become earth. In any case, the importance of this early thinker lies in the fact that he raised the question, what is the ultimate nature of the world; and not in the answer that he actually gave to the question or in his reasons, be they what they may, for giving the answer.”

b) charge [ 'ηλεκτρον (the substance amber) = electron; ~ 600 BC ] The ancient Greeks recognized that rubbing certain materials (friction) produced changes in that material, particularly with respect to its effect on other materials.

Today we know that charge is a characteristic of an atom or molecule which expresses either the loss or gain of electrons. c) Democritus (468-370 BC) ; Epicurus (342-270 BC) Democritus postulated that matter was not infinitely devisable, but that there was a limit to which it could be divided. The limiting case of minute, indivisible particles he called an atom ( άτομο ).

d) Aristotle (384-212 BC) Apart from his foundational contributions to Philosophy, Aristotle was the first to formulate a theory of Chemistry, and to link this to an explanation of motion. In ancient Greek, his 'kinesis' ( κίνησις ) literally means movement or to move. i) “Chemistry”: four elements on Earth: Earth, Air, Fire, Water ; in the Heavens: a fifth element αἰθήρ = aether; quintessence. ii) “Physics”: All bodies move toward their Natural Place on Earth. For the elements Earth and Water, that place is the center of the (geocentric) universe; the natural place of water is a concentric shell around the earth because earth is heavier; it sinks in water. The natural place of Air is likewise a concentric shell surrounding that of water; bubbles rise in water. The natural place of Fire is higher than that of air but below the innermost celestial sphere (carrying the Moon). 2. Ideas from the Intellectual Revolution in the 17th Century a) mass For nearly 2000 years, people held to Aristotle’s “common sense” theory of “natural place” and motion, that a falling object had a definite “natural falling speed” proportional to its weight. Hence, in dropping two objects of different weight, the heavier object should hit the ground first. In his inclined-plane experiment, the 26 year old Galileo found that the speed just kept increasing, and weight was irrelevant as long as friction was negligible. Both objects hit the ground at the same time. He recognized that the speed (velocity) of an object changes on falling (the concept of acceleration). This groundbreaking experiment was captured in the legend that Galileo dropped two cannonballs from the top of the Leaning Tower in his hometown of Pisa in Italy. The Leaning Tower of Pisa History & Facts | LivItaly Tours Check out:

Feather & Hammer Drop on Moon - YouTube
The concept of mass as a quantitative measure of inertia was introduced by Galileo (1564 – 1642) , then adopted and quantified by Newton (1642 - 1727) [ Newton was born in the year Galileo died; for historical reference, Michelangelo died in 1564, and Shakespeare was born in 1564]. Inertia is a fundamental property of all matter. It is, in effect, the resistance that a body of matter offers to a change in its speed or position upon the application of a force. The greater the mass of a body, the smaller the change produced by an applied force. The following is what Newton proposed on the inter-relationship between mass, change in position with time (velocity, acceleration), and force. Three Laws of Motion: The first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force (F). The second law states: Force = mass x acceleration. F = ma. The third law states that for every action (force) in nature there is an equal and opposite reaction.

Using these three laws (after inventing a new branch of mathematics, calculus, to solve the problem) he proved the following: Law of Universal Gravitation; Objects with mass feel an attractive force that is proportional to their masses and inversely proportional to the square of the distance (R). F = G m m’ / R^2 (G = a constant) Importantly, this is a universal Law of Nature, applicable to processes in the nucleus, to atoms and molecules, to the macroscopic processes we study on planet Earth, to Black Holes, to events in the farthest reaches of the Universe, back to the Big Bang, a singularity in the fabric of time and space that occurred ~ 14 billion years ago. Discovery of this mind-blowing general law is one of the reasons why Newton is regarded as the greatest scientist (ever). Later in the course we will find that he also made fundamental contributions to our understanding of light, elaborated in his book Opticks.jpg c) Conservation of Charge ( Franklin: 1706 – 1790 ; Coulomb: 1736 – 1806 ) Benjamin Franklin proposed a one-fluid theory of electricity. He imagined electricity as being a type of invisible fluid present in all matter. He posited that rubbing insulating surfaces together caused this fluid to change location, and that a flow of this fluid constitutes an electric current. He also posited that when matter contained too little of the fluid it was negatively charged, and when it had an excess it was positively charged. Franklin laid the foundation for a very important principle: unlike charge can cancel each other, but the total amount of charge is never changed. Charge is neither created nor destroyed, although + and – charge can neutralize each other, and two kinds of charge in a neutral object can often be separated. No exceptions have ever been found. Diagrams of various electrical phenomena o Experiments and Observations on Electricity. Library of COngress

Coulomb found experimentally that: The magnitude of the electrostatic force (F) of attraction or repulsion between two point charges (q) is directly proportional to the product of the magnitudes of charges ( q x q’ ) and inversely proportional to the square of the distance (R) between them. F = K q q’ / R^2 (K = constant) Notice the similarity in the mathematical structure of the Law of Universal Gravitation and Coulomb’s Law. Both involve an inverse dependence on the distance, viz., 1/R2. A product in the numerator, m x m, for Gravitation, q x q for charge interactions. Two significant differences: the constants are different and have very different values (K >>G). And, most importantly, gravitational interactions are always attractive, whereas electrical interactions can be either attractive or repulsive. The latter point is a cardinal principle throughout Chemistry. “Like charges repel, unlike charges attract.” b) Conservation of Mass (Lavoisier, 1793) So, finally, we come to Lavoisier. As a college student Lavoisier read Newton’s famous book, Philosophiæ Naturalis Principia Mathematica. Notice that it was written in Latin. At some point, Lavoisier realized that he could begin to quantify the jungle of empirical observations about chemical reactions if he focused on the Galilean/Newtonian concept of mass. Now, we’re off to the races!!! See below for a diagram of Lavoisier’s instruments and his description of his seminal experiment.

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Above shows Lavoisier’s apparatus for studying mercury oxidation in closed environment described in his Traité Élémentaire de Chimie published in 1789 The system contained mercury (Hg) Pouring liquid mercury bionerd.jpg in a resort (called a matrass) and normal air sealed by a bell jar placed in the mercury reservoir. After heating the mercury in the resort for several days, red mercury oxide (HgO) Mercury(II) oxide was observed on the mercury surface. The mercury level inside the bell jar rose up because the consumption of oxygen. When the amount of mercury oxide no longer increased, the heating was terminated and the amount of gas volume decrease was measured. Lavoisier found that the gas loss was 16% of the total volume. The mercury oxide was removed and heated again, the volume of oxygen generated was measured. It was found that the volume was the same as the 16% volume loss. The oxygen percentage (16%) was not accurate, which could be due to not all oxygen react with mercury. From this experiment, we recognize Lavoisier’s emphasis on the Conservation of Mass in his experiment design.

In Lavoisier’s own words: I took a matrass of about 36 cubic inches, having a long neck of six or seven lines internal diameter, and having bent the neck so as to allow of its being placed in the furnace, in such a manner that the extremity of the neck might be inserted under a bell glass, placed in a trough of quicksilver (mercury). I introduced four ounces of pure mercury into the matrass and, by means of a siphon, exhausted the air in the receiver, so as to raise the quicksilver, and I carefully marked the height at which it stood by pasting on a slip of paper. Having accurately noted the height of the thermometer and barometer, I lighted a fire in the furnace, which I kept up almost continually during twelve days, so as to keep the quicksilver almost at its boiling point. Nothing remarkable took place during the first day: the mercury, though not boiling, was continually evaporating and covered the interior surface of the vessel with small drops, at first very minute, which gradually augmenting to a sufficient size, fell back into the mass at the bottom of the vessel. On the second day, small red particles began to appear on the surface of the mercury, which, during the four or five following days, gradually increased in size and number, after which they ceased to increase in either respect. At the end of twelve days seeing that the calcination (ancient word for what today is called oxidation) of mercury did not at all increase, I extinguished the fire, and allowed the vessel to cool. The bulk of air in the body and neck of the matrass, and in the bell glass, reduce to a medium of 28 inches of the barometer and 10o (54.5o F) of the thermometer, at the commencement of the experiment was about 50 cubic inches. At the end of the experiment the remaining air, reduced to the same medium pressure and temperature, was only between 42 and 43 cubic inches; consequently it had lost about 1/6 of its bulk. Afterwards, having collected all the red particles formed during the experiment from the running mercury in which the floated, I found these to amount to 45 grains. The air which remained after the calcination of the mercury in this experiment, and which was reduced to1/6 of its former bulk, was no longer fit either for respiration or combustion; animals being introduced into it were suffocated in a few second, and a taper was plunged into it, it was extinguished as if it had been immersed in water. (In fact, he had discovered the presence of the element nitrogen). Lavoisier then carried out the reverse experiment, heating the product (mercuric oxide) measuring the amount of mercury that was produced and the gas (oxygen) that evolved.. Weights were taken again it was found that the weight of the reactant matched the weight of the two products. As for the gas that was produced, a taper burned in it with a dazzling splendor and charcoal, instead of consuming quietly as it does in common air, burned with a flame, attended with a decrepitating noise, like phosphorus, and threw out such light the eyes could hardly endure it. BALANCING EQUATIONS The Law of Conservation of Mass, as implemented at the atomic/molecular level in balancing equations, is more than just an abstract idea. It is the bedrock of the chemical industry. Suppose, for example, you want to produce sulfuric acid (H2SO4), the substance most produced by the chemical industry World-wide. (Guess why ???) In the first step of the production, sulfur (a solid) is oxidized to produce sulfur dioxide, SO2. S (s) + O2(g) SO2 SO2 is then oxidized to sulfur trioxide using oxygen in the presence of a vanadium (V) oxide catalyst. 2 SO2(g) + O2(g) 2 SO3(g) An intermediate is then formed, oleum (H2S2O7), called fuming sulfuric acid , which, dissolved in water, gives H2SO4 . If the coefficients were ignored in the second equation, you would have no quantitative idea how much sulfuric acid would be produced in the process. Practically speaking, you would have no idea how many train loads of sulfur from Louisiana should be brought to the plant, and the “bottom line” would be a disaster. Too little sulfur or too much sulfur would wipe out the profit margin. Below is taken from a Wikipedia website on “balancing equations.” Spending time reviewing the examples given will help understanding material later on in the course.

Balancing Equations: Practice Problems Try your hand at balancing each of the following equations. The correct answers follow. (a) Fe+ Cl2 → FeCl3 (b) Fe+ O2 → Fe2O3 (c) FeBr3 + H2SO4 → Fe2 (SO4 )3 + HBr (d) C4H6O3 + H2O → C2H4O2 (e) C2H4 + O2 → CO2 + H2O (f) C4H10O+ O2 → CO2 + H2O (g) C7H16 + O2 → CO2 + H2O (h) H2SiCl2 + H2O → H8Si4O4 + HCl (i) HSiCl3 + H2O → H10Si10O15 + HCl (j) C7H9 + HNO3 → C7H6 (NO2) 3 + H2O (k) C5H8O2 + NaH + HCl → C5H12O2 + NaCl Answers to Practice Problems. (a) 2 Fe+ 3 Cl2 →2 FeCl3 (b) 4 Fe + 3 O2 → 2 Fe2O3 (c) 2 FeBr3 + 3 H2SO4 → Fe2 (SO4 )3 + 6 HBr (d) C4H6O3 + H2O → 2 C2H4O2 (e) C2H4 + 3 O2 → 2 CO2 +2 H2O (f) C4H10O +6 O2 →4 CO2 + 5 H2O (g) C7H16 + 11 O2 → 7 CO2 + 8 H2O (h) H2SiCl2 + H2O → H8Si4O4 + HCl (i) 10 HSiCl3 + 15 H2O → H10Si10O15 + 30 HCl (j) C7H9 + 3 HNO3 → C7H6 (NO2) 3 + 3 H2O (k) C5H8O2 + 2 NaH + 2 HCl → C5H12O2 + 2 NaCl