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History
This observation was first made by the French chemist Joseph Proust based on several experiments conducted between 1798 and 1804.For example: Proust, J.-L. (1799). Researches on copper, Ann. chim., 32:26-54. Excerpt, in Henry M. Leicester and Herbert S. Klickstein, A Source Book in Chemistry, 1400-1900, Cambridge, MA: Harvard, 1952. Accessed 2008-05-08. Based on such observations, Proust made statements like this one, in 1806:- "I shall conclude by deducing from these experiments the principle I have established at the commencement of this memoir, viz. that iron like many other metals is subject to the law of nature which presides at every true combination, that is to say, that it unites with two constant proportions of oxygen. In this respect it does not differ from tin, mercury, and lead, and, in a word, almost every known combustible." Read full entry
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- 1.Law of definite proportions - Wikipedia, the free encyclopedia
- (Redirected from Law of constant composition) Jump to: navigation, search ... equivalent statement is the law of constant composition, which states that all ...
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aw_of_constant_composition
- 2.Law of Constant Composition
- Many textbooks have suggested experiments about the law of constant composition: ... an experiment that you can do that will show the Law of Constant Composition. ...
- http://www.saskschools.ca/curr
_content/science10/unitb/lawco mp.html
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What does the law of constant Law of Composition: A given
compound always contains the
same elements in the same
proportions by mass.
1. What does the above
statement mean?
2. For example, does
CuSO4*5H2O follow the law of
constant composition? Why or
why not?
3. Give an example with
another chemical. :]
Thanks~
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Your satement Law of constant composition is fine. But a better one: A particular compound will always have same elements in same (constant) proportion irrespective of its source or method of preparation. For example H2O can be obtained from different places and sources or by different methods. So long it is pure water the proportion of hydrogen and oxygen by mass will be same in all the samples. You can get water by melting ice or snow, condensing steam, from river, sea, pond. etc. It can be from different places USA, UK, Australia, or from any where. It can be made by chemical reactions like burning H2 in oxygen, or by neutralization of acid and base (NaOH / HCl or KOH / H2SO4). If water is pure it will have same (constant) composition irrespective of its source / place of source / method of preparation. CuSO4.5H2O or in fact every other compound follow this law. |
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What does the law of constant and the law of multiple
proportions.
please explian becasue i dont
seem to understand it that
well.
thank you!
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Law of Constant Composition or Law of Definite Proportions: "Law which states samples of a pure compound always contain the same elements in the same mass proportion." All compounds have the same chemical formula. Makes sense, no? Law of Multiple Proportions: Quoted: "Let's see an example: Hydrogen can react with oxygen in a couple of different ways. One way occurs when you take two moles of hydrogen and react it with one mole of oxygen. When you do this, you make H2O. Another way occurs when you take one mole of hydrogen and react it with one mole of oxygen: When you do this, you make H2O2. What you'll find is that any time two elements can form more than one compound with each other, this kind of relationship between the masses takes place." This means that two elements can combine in 1 or more ways. Hence, multiple proportions. |
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Which of the following is an 1)Water boils at 100
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I think its # 5, because no matter which mass water has, the composition will always be 11% hydrogen and 89% oxygen |
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