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The Gay-Lussac's Law of Combining Volumes states that when gases react, they do so in volumes, which are in simple ratio to one another and to the volume of the product, if any; provided temperature and pressure remain constant. It applies to only gases, which means that solid and liquid reactants and products are always ignored when applying this law. For instance, hydrogen burns in oxygen at 100°C to form steam according to the equation:        2H2(g) + O2(g) ---> 2H2O(g)          2mol      1mol           2mol          2vol        1vol            2vol          2cm^3    1cm^3        2cm^3 From the above, it implie...

Mole concept is arguably the broadest topic in chemistry, as it cuts across every other branch of chemistry, as far as reactions are concerned. It is the foundation of calculations in chemistry.  Chemical reactions, expressed as equations, are ways of confirming the Law of Conservation of Mass, which states that matter is neither created nor destroyed, but is transformed from one form to another . This is also what was paraphrased in one of the postulations of Dalton's Atomic Theory, which is, atoms are neither created nor destroyed (during a chemical reaction), but are changed from one form to another . The above implies that if two substances A and B combine to give another substance C, i.e,              A  +  B  --->  C then, the total masses of A and B will equal the mass of C. In other words, all of A and B will be converted to C, assuming there is no loss. Meaning that if we know the m...

Summary Of Atomic Models After John Dalton's postulations of the Atomic Theory, several scientists carried out investigations on the structure of the atom to either validate or disapprove the theory. This eventually led to its modifications, as only one out of the five postulations made by Dalton was and is still valid, i.e., all chemical changes result from the combination or the separation of atoms . The results of the major studies of are summarized below: J . J . Thompson Using his discharge tube and cathode rays experiments, he discovered that an atom is made up of positively charged particles called protons, and negatively charged particles called electrons. He went on to propose that the atom is a sphere of positively charged matter in which negatively charged electrons are embedded . His model looks like an orange filled with seeds. Ernest Rutherford Through his gold-foil experiment, he proposed that the atom is made up of a positive core...

These ten two-lettered words, which have made a deep impression in me, take me back to my years in the university. As a student, I was a keen reader of Zig Ziglar's works. I had stumbled across one of his best sellers, 'See You At The Top', and could not put it down until I devoured all the pages. So, during my mandatory national youth service in Zamfara State; when I came across 'Over The Top' (a sequel to the former title), I quickly grabbed it and literally, started chewing the pages. It was in one those pages that I came across a quote of these powerful two-lettered words. There was also a story behind the quote, which I will like to share (in my own version). So, enjoy and learn the lesson! Once upon a time, in a mountainous village, there lived an old hermit, who was renowned for his wisdom. In fact, he was acclaimed to be the wisest man in the world as at that time. In that same village, down the valley, there resided two little boys, who were in their early...

The oxidation number of an element in a compound or radical   is the valency or combining power of the element in that compound or radical. It is also defined as the electrical charge an element appears to have in a given molecule or ion. The importance of oxidation number in chemistry cannot be overemphasized, as it can be used to predict the nature of a reaction. A change in oxidation number is used to reflect an electron gain or loss in a reaction. If the oxidation number increases, it means there is an electron loss (oxidation), while a decrease in oxidation number shows an electron gain (reduction). Determining the oxidation numbers of element follows a set of rules as discussed below: Rules For Determining Oxidation Numbers 1) The oxidation number of all elements in the free state is zero. By free state, we mean their uncombined state with any other element. e.g., F2, Mg, O3, Cl2, S, Ca, K, Na, Zn etc. 2) The oxidation number of a simple ion is equal to the charge...