Video Transcript
Complete the following with the
correct chemical formula of the product, or products, we get when carbon dioxide
dissolves in water: CO2 plus H2O react to form blank. (A) CO3 plus H2, (B) CO plus H2CO2,
(C) O3 plus H2 plus C, (D) CH2O plus O2, (E) H2CO3.
In this question, we are given an
incomplete chemical equation for a chemical reaction. In a chemical equation, the
reactants always appear on the left side of the reaction arrow and the products
appear on the right. We are told that the names of the
reactants of the chemical reaction are carbon dioxide and water. CO2 is the chemical formula of
carbon dioxide, and H2O is the chemical formula of water.
To answer the question correctly,
we must determine the chemical formula of the product or products of this
reaction. Carbon dioxide is a type of
chemical compound called an oxide. There are two main types of oxide
compounds: nonmetal oxides and metal oxides. A nonmetal oxide is a covalent
compound that contains the element oxygen and another nonmetal element. A metal oxide is an ionic compound
that contains a metal element and oxygen.
Nonmetal oxides and metal oxides
have different chemical properties. When a nonmetal oxide dissolves in
water, a new compound called an acid is formed. A different compound is produced
when a metal oxide dissolves in water. When a metal oxide dissolves in
water, an alkali is formed. This is why chemists call nonmetal
oxides acidic oxides and call metal oxides basic oxides.
Let’s determine what type of oxide
carbon dioxide is. A carbon dioxide molecule contains
one carbon atom and two oxygen atoms. Both carbon and oxygen are nonmetal
elements. This means carbon dioxide is a
nonmetal oxide or an acidic oxide.
Now we know that when carbon
dioxide dissolves in water, an acid will be produced. We can often identify an acid from
its chemical formula. Many acids are composed of the
element hydrogen and at least one other nonmetal element. Let’s think about the acid
hydrochloric acid. Its chemical formula is HCl. H is the chemical symbol for
hydrogen, and Cl is the chemical symbol for the nonmetal element chlorine. In the chemical formula of many
acids, one or more hydrogen atoms are written first.
When looking at the answer choices,
we can see that there are only two choices that contain an acid, choices (B) and
(E). In choice (B), we know that the
chemical formula H2CO2 represents an acid because the hydrogen atoms are written
before the other nonmetal elements. Likewise, in choice (E), we know
that the chemical formula H2CO3 represents an acid because the hydrogen atoms are
also written before the other nonmetal elements. Something else that we notice is
that in choice (B), two different products are listed: CO and H2CO2. But in choice (E) only one product
is listed: H2CO3.
When a nonmetal oxide dissolves in
water, only one product is produced, the acid. So, answer choice (E) must be the
correct answer. The chemical formula of the acid
produced in the reaction is H2CO3, and the name of this acid is carbonic acid. In conclusion, the chemical formula
of the product that correctly completes the equation is H2CO3 or answer choice
(E).
