Video Transcript
Nitrogen and oxygen in the air can
combine in a series of reactions to produce a variety of nitrogen oxides. Using the concept of conservation
of elements, determine which of the following could not be a possible product of
these reactions? (A) N2O3, (B) HNO3, (C) NO2, (D)
N2O5, or (E) NO.
All chemical reactions must obey
the concept of conservation of elements. This means that atoms of elements
cannot be created or destroyed during a chemical reaction. In other words, all elements which
appear in the reactants or starting materials must also appear in the products and
vice versa.
In this question, we are told that
nitrogen and oxygen in the air can combine in a series of reactions to produce a
variety of nitrogen oxides. Using what we know about the
conservation of elements, we need to determine which of the answer choices could not
be a possible product. Nitrogen and oxygen in the air are
the reactants or starting materials of this reaction. Nitrogen in the air consists of two
nitrogen atoms and is represented by capital N subscript two. Oxygen in the air consists of two
oxygen atoms and is represented by capital O subscript two. So the reactants only contain the
elements nitrogen, chemical symbol capital N, and oxygen, chemical symbol capital
O.
Since all elements which appear in
the reactants must also appear in the products and vice versa, nitrogen oxides can
only contain the elements nitrogen and oxygen, although the number of nitrogen and
oxygen atoms represented here by the subscripts 𝑥 and 𝑦 will differ depending on
the variety of nitrogen oxide.
Looking at the answer choices, we
can see that each contains the elements nitrogen and oxygen. However, the product shown in
answer choice (B) also contains the element hydrogen. Since we have established that
nitrogen oxides can only contain the elements nitrogen and oxygen, answer choice (B)
cannot be a possible product of this reaction because it contains the element
hydrogen. So the substance which could not be
a possible product of the reaction between nitrogen and oxygen to produce a variety
of nitrogen oxides is the substance shown in answer choice (B), HNO3.
