Conservation of matter

Besides equilibrium constant equations, two other types of equations are used in the systematic approach to solving equilibrium problems. The first of these is a mass balance equation, which is simply a statement of the conservation of matter. In a solution of a monoprotic weak acid, for example, the combined concentrations of the conjugate weak acid, HA, and the conjugate weak base, A , must equal the weak acid s initial concentration, Cha- ... 

In chemical reactions, when the atomic configurations of molecules are changed, matter is neither created nor destroyed (Law of Conservation of Matter). The identity and number of atoms remain unchanged. When methane gas (Cl L) is burned, its atoms don t disappear they combine with oxygen (O,) in the air and are transformed into carbon dioxide (CO,) and water vapor (H,0) ... 

The design of a reactor starts with the expression of material balance for any reactant (or product). The basis for all material balances is the law of conservation of matter, which states that matter cannot be created or destroyed in a given system (nuclear reactions are, of course, out of this dictum). Material balance is generally given as ... 

In a chemical equation, like the one for the reaction between sulfuric acid and potassium hydroxide, the reactants (the substances being mixed together) are always written on the left-hand side of the equation. The products (the substances made when the reactants react with each other) are placed on the right-hand side of the equation. Atoms cannot be made or destroyed in a chemical reaction, only rearranged. This is called the law of conservation of matter. Therefore, there must always be the same number of atoms of each element on the reactant side of the equation as there are on the product side. 

Now there are four hydrogen atoms on the reactant side (two in sulfuric acid and one in each of the two molecules of potassium hydroxide) and four hydrogen atoms on the product side (two in each of the two molecules of water). All of the other atoms have equal numbers on each side as well. Now the equation conforms to the law of conservation of matter, and it is a balanced chemical equation. 

Law of conservation of matter A law that states that matter can... 

The increase in mass is just the mass of the combined oxygen. When a log burns, the ash which remains is much lighter than the original log, but this is not a contradiction of the law of conservation of matter. In addition to the log, which consists mostly of compounds containing carbon, hydrogen, and oxygen, oxygen from the air is consumed by the reaction. In addition to the ash, carbon dioxide and water vapor arc produced by the reaction. 

The total mass of the ash plus the carbon dioxide plus the water vapor is equal to the total mass of the log plus the oxygen. As always, the law of conservation of matter is obeyed as precisely as chemists can measure. The law of conservation of mass is fundamental to the understanding of chemical reactions. Other laws related to the behavior of matter are equally important, and learning how to apply these laws correctly is a necessary goal of the study of chemistry. 

The Law of Conservation of Matter provides the basis for balancing a chemical equation. It states that matter is neither created nor destroyed during an ordinary chemical reaction. Therefore, a balanced chemical equation must always contain the same number of each kind of atom on both sides of the equation. 

Due to the Law of Conservation of Matter, electrons cannot be created or destroyed in chemical reactions. The electrons that cause the reduction of one substance must be produced from the oxidation of another substance. Therefore, oxidation and reduction always occur simultaneously in ordinary chemical reactions. 

If Kc were very large, at equilibrium we would have essentially all A2 and very little A. The Law of Conservation of Matter is not violated because wherever the system is, the total mass of the system remains constant mass of A + mass of A2 = constant. 

Recall that for other reactions we have studied which we know obey the Law of Conservation of Matter, we assumed they went totally to completion. At the beginning of the reaction, there were only reactants and at the end, there were only products. 

In a nuclear reaction, there is no conservation of matter as in ordinary chemical reactions. 

A balanced chemical equation provides many types of information. It shows which chemical species are the reactants and which species are the products. It may also indicate in which state of matter the reactants and products exist. Special conditions of temperature, catalysts, etc., may be placed over or under the reaction arrow. And, very importantly, the coefficients (the integers in front of the chemical species) indicate the number of each reactant that is used and the number of each product that is formed. These coefficients may stand for individual atoms/molecules or they may represent large numbers of them called moles (see the Stoichiometry chapter for a discussion of moles). The basic idea behind the balancing of equations is the Law of Conservation of Matter, which says that in ordinary chemical reactions matter is neither created nor destroyed. The number of each type of reactant atom has to equal the number of each type of product atom. This requires adjusting the reactant and product coefficients—balancing the equation. When finished, the coefficients should be in the lowest possible whole-number ratio. 

Conservation of Matter says that, in ordinary chemical reactions, matter is neither created nor destroyed. 

A chemical reaction is said to be balanced when the number of atoms of each element is equal in the reactants and products. Because of the conservation of matter, equations are always balanced. You cannot represent the reaction of hydrogen and oxygen as... 

Lavoisier, A.L. (1743—1794). Fr Chemist, regarded as the father of modern chemistry by virtue of his study of combstn and the role of oxygen. He formulated the theory of the conservation of matter, and laid the basis for chemical nomenclature. From 1775 to 1791 he was in charge of expl manufg in Fr ( Regisseur des Poudres ). He was unjustly accused and executed during the Fr revolution Ref Hackh s (1944), 481-R (1969), 381-R... 

If the entire system consists of only two phases, the hypothesis here, the conservation of matter requires that any substance lost from one phase must appear in the other ... 

Now the probability of reactants 1 and 2 simultaneously being at rj and r2 is n(r1,r2). The two-body density or concentration changes with time due to a net flux into the small volume drtdr2, that is the law of conservation of matter or the equation of continuity of mass... 

The mass balance is a statement of the conservation of matter. It really refers to conservation of atoms, not to mass. 

Eqn. (8.71) constitutes (n-1) differential equations for the spatial distribution of n components in the crystal. The set of equations is complete if the conservation of matter is taken into account. For a binary system (1—2), Eqn. (8.71) is particularly simple to handle since it reduces to... 

Conservation of Matter. This is the familiar statement that "mailer is neither destroyed nor created." There must be a weight balance between the sum of the weights entering a process and the sum leaving. In other words. A pounds of fuel combined with B pounds of air will always result in A + B pounds of products. (It should be noted that when a pound of a typical coal is burned, releasing 13.500 Btu, the quantity of mass converted to energy amounts to only 3.5 x 10 1(1 pound, a loss too small to be measured or considered in conventional combustion calculations. Obviously, this conversion is of significance to nuclear reactions.)... 

When we make a balance to obtain a differential equation, we are invoking a natural law, the conservation of matter in our case. If the net flux of any conserved quantity into a lumped system over its boundaries is F, the rate of generation within the system is G, and the amount contained in it is H, then the balance gives... 

---