What is the Law of Conservation of Mass - Book Report/Review Example

What is the Law of Conservation of Mass? The law of conservation of mass states that the mass of a given system does not change in any ordinary chemical reaction or more simply, the mass of reacting species is always equal to the mass of the substances formed by a chemical reaction (Sterner). b. Who developed it? The law of conservation of mass was developed by Antoine Laurent Lavoisier, a French chemist, in 1789 (Lavoisier and the Law of Conservation of Mass). c. Describe the experiments this person carried out that led to the law’s formulation. Lavoisier was able to carry out a series of laboratory experiments that led to the formulation of this law. These experiments (which are as follows) are done in closed vessels, in which of course the mass of species involved in the reaction remained constant all throughout. (1) One experiment performed by Lavoisier involved heating a sealed glass vessel containing a sample of tin and some air. Lavoisier found that before heating, the mass of the entire system (vessel + tin + air) is equal to the mass of the system after heating (vessel + tin calx + remaining air). In this experiment, tin calx (which is now known as tin oxide) is the product of the reaction which he showed that it consisted of the tin together with a portion of the air. (2) Another experiment done by Lavoisier was on red mercury compound in which he boiled the former in a sealed apparatus. After reaction has occurred, aside from the formation of oxygen gas, the red mercury became silvery liquid. Lavoisier confirmed by weighing the apparatus that the chemical species were the same in quantity before and after the experiment (Zinni). d. Which of Dalton’s four principles does it support, and how does it support it? The second principle (atoms are neither created nor destroyed in chemical reactions) supports the law of conservation of mass. Since atoms are present in all matter, then this principle by Dalton truly explains the law of conservation of mass. 2. a. What is the law of definite proportions? The law of definite proportions (also known as law of constant composition) states that all samples of a particular compound have the same composition – the same proportions by mass of the constituent elements (wiseGEEK). b. Who developed it The law of definite proportions was developed and declared by Joseph Proust, a French chemist, in 1806 (Carson). c. Describe the experiments this person carried out that led to the laws formulation. Joseph Proust discovered this law when he was conducting some experiments that involved determination of chemical formulas. Most of his experiments were done primarily on metal compounds (the very common one is on oxides of copper). He reacted several elements with oxygen and he found out that amount of oxygen in the product from these reactions was always fixed at one or two values. Another experiment of Proust that led to the discovery of law of definite proportions was on copper (II) carbonate. Proust showed that this compound always had 5.3 parts copper to 1 part carbon to 4 parts oxygen (Joseph Louis Proust). 3. a. What is the law of multiple proportions The law of multiple proportions is a statement that when two or more elements form more than one compound, the mass ratios of the elements in the compounds are simple whole numbers of each other. b. How is different from the law of definite proportions? The laws of definite proportions and multiple proportions have something to do with relating Dalton’s Atomic Theory. The difference is that the former concerns itself with the combination of elements for the formation of one compound which results to a simple whole number ratio, meaning to say that no matter how a compound is produced, it has to have the same elements ratio. On the other hand, the latter has something to do with comparison between two same elements that make up two different compounds where the division of these two ratios should be a simple whole number ratio. This means that this law pertains to different chemical compounds that can be produced whenever two elements react (Petrucci). c. Who developed it? John Dalton developed law of multiple proportions when he was studying different binary compounds. d. What experimental evidence led to the law’s formulation? When John Dalton was on the verge of discovering this law, he made a quantitative and experimental study of different compounds made from the same elements such as carbon monoxide, carbon dioxide, etc. Such a study became experimental evidence which led to formulating the law of multiple proportions (Petrucci). e. Which of Dalton’s four principles does it support, and how does it support it? The third principle (atoms of different elements combine in whole number ratios, with more than one ratio being possible for a given combination of elements) supports the law of multiple proportions. This principle supports the law of multiple proportions in such a way that if atoms unite in fixed numerical ratios, the percent composition of a compound must have a unique value, regardless of the origin of the sample being analyzed (Petrucci). 4. 1 g of hydrogen will react with 19 g of fluorine to form HF. By contrast, 1 g of hydrogen will react with 80 g bromine to form HBr. a. How many grams of each product will form in each reaction? Based on the law of conservation of mass, the mass in grams of each product in each reaction: For the reaction between 1 g H and 19 g F Mass of HF formed = mass of H + mass of F = 1 g + 19 g = 20 g For the reaction between 1 g H and 80 g Br Mass of HBr formed = mass of H + mass of Br = 1 g + 80 g = 81 g b. Why are different amounts of each element required to react with the same amount of hydrogen? Different amounts of each element are required to react with the same amount of hydrogen since 1 mole of hydrogen weighs 1 g. When bromine and fluorine react with hydrogen in separate reactions, the mole ratio is 1:1, which means that 1 mole of hydrogen is needed for every 1 mole of fluorine or bromine that will be used up in the reaction. Take note that for every 1 mole of fluorine and bromine, the corresponding masses are 19 g and 80 g, respectively. Therefore, to completely answer this question, the reaction is done with same amount of hydrogen because these reactions take place in terms of moles of substances. c. Which of Dalton’s four principles does this observation support, and how does it support it? The fourth principle (each element is made of a different kind of atom, and the atoms of different elements have different masses) supports this observation. In a similar manner as how the third principle supports the law of multiple proportions, the fourth principle supports the said observation in a way that if all atoms of an element are alike in mass then the percent composition of a compound must have a unique value, regardless of the origin of the sample being analyzed (Proust / Dalton & The Laws of Definite and Multiple Proportions). Works Cited Petrucci, Ralph H., and Harwood, William S. General Chemistry: Principles and Modern Applications. Seventh edition. Singapore: Simon and Schuster (Asia) Pte Ltd., 1998. Sterner, Robert W. “The Conservation of Mass.” The Nature Education. 2012. Web. 17 Jan 2013. http://www.nature.com/scitable/knowledge/library/the-conservation-of-mass-17395478. “Lavoisier and the Law of Conservation of Mass.” 2012. Web. 17 Jan 2013. http://www.chemteam.info/Equations/Conserv-of-Mass.html Zinni, Yasmin. “Lavoisier’s Discoveries.” 2013. Web. 17 Jan 2013. http://www.ehow.com/info_8153097_lavoisiers-discoveries.html Carson, Nacie. “About the Law of Definite Proportions.” 2013. Web. 17 Jan 2013. http://www.ehow.com/about_4570091_law-definite-proportions.html “What is the Law of Definite Proportions?” wiseGEEK. 2013. Web. 18 Jan 2013. http://www.wisegeek.com/what-is-the-law-of-definite-proportions.htm “Joseph Louis Proust.” 2013. Web. 18 Jan 2013. http://www2.ucdsb.on.ca/tiss/stretton/CHEM1/history_Proust.html “Proust / Dalton & The Laws of Definite and Multiple Proportions.” 2013. Web. 18 Jan 2013. http://www.sussexvt.k12.de.us/science/The%20Atom/Proust.htm Read More