Arsenic reacts with oxygen to form oxides that react with...

Key Concepts

Hydrolysis of Oxides

Hydrolysis refers to the reaction of an oxide with water to produce an oxyacid. Here, the arsenic pentoxide reacts with water to generate arsenic acid, analogous to the reaction of phosphorus pentoxide with water to yield phosphoric acid, illustrating the conversion of a nonmetal oxide into its corresponding acid.

Oxidation Reaction

This concept involves the process in which a substance (in this case, elemental arsenic) combines with oxygen, resulting in an increase in its oxidation state. Such reactions are fundamental in inorganic chemistry and demonstrate how elements react with oxygen to form corresponding oxides.

Oxide Formation

In the context of this reaction, oxide formation pertains to the creation of a compound consisting of arsenic and oxygen (arsenic pentoxide). Similar to phosphorus forming P4O10, arsenic forms As2O5 under certain conditions, reflecting trends in the behavior of elements within the same group.

Stoichiometry and Balancing Chemical Equations

A key aspect of writing chemical reaction equations is ensuring that the number of atoms of each element is conserved on both sides of the equation. This involves careful accounting and balancing of reactants and products, which is a critical skill in understanding and representing chemical reactions accurately.

Transcript

00:01 So in this way here we're going to be working through problem 50 from chapter 20, which says arsenic reacts with oxygen to form oxides that react with water in a manner analogous to that of the phosphorus oxides.

00:12 Right balanced chemical equations describing the reaction of arsenic with oxygen and the reaction of the resulting oxide with water.

00:19 So we know we have arsenic coming together with oxygen, as plus o2, and we're forming an arsenic oxide.

00:26 But we need to figure out the formula of the arsenic oxide.

00:30 So we know that arsenic, because of the column or 3 % in the periodic table, is going to want to form a plus 3 oxidation state, while oxygen is going to want to form a minus 2 oxidation state.

00:46 So we have minus 2 and plus 3.

00:48 The least common multiple of 2 and 3 is 6.

00:50 So we're going to need 3 of our negatively charged anion.

00:56 Three of our minus two charges and two of our plus three charges in order for this to be balanced.

01:01 So the formula for the arsenic oxide is as203, arsenic trioxide.

01:09 So how do we balance this? so just starting out, i can see that i have an odd number of oxygen atoms on the right and an even number on the left.

01:17 So i'm going to put a coefficient of two in front of my as203 to make that an even number.

01:22 So now i have six oxygen atoms on the right and just two on the left.

01:27 So i'm going to put a coefficient of three in front of my o2.

01:30 And now i have the same number of oxygen atoms on both sides of the equation.

01:35 So that's balanced.

01:36 But i have four arsenic atoms in my product and only one arsenic atom in my reactant...

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