Figurę 7.4 In a decomposition reaction, one reactant breaks down into two or morę products.
Howdo the diffierences in the reactant and products classify this as a decomposition reaction?
2 HgO(j) Mercury(II) oxide
2 Hg(/) Mercury
+ 02(g)
Oxygen
A splits reactant into
A B
In a decomposition reaction, a single reactant splits into two or morę products. For example, when mercury(II) oxide is heated, the products are mercury and oxygen. (See Figurę 7.4.)
2HgO(i) 2Hg(i) + 02(g)
In another example of a decomposition reaction, calcium carbonate breaks apart into simpler compounds of calcium oxide and carbon dioxide.
CaCO3(j) -A* CaO(s) + C02(g)
In replacement reactions, elements in compounds are replaced by other ele-ments. In a single replacement reaction, an uncombined element takes the place of an element in a compound.
Single replacement
One element replaces anothet element
In the single replacement reaction shown in Figurę 7.5. zinc replaces hydrogen in hydrochloric acid, HC1 (aq).
Zn (s) + 2HC1 (aq) ZnCl 2{aq) + U2(g)