Question

identifying types of chemical reactions - swyk which one of the following is a decomposition reaction? ch₄ (g) + 2o₂ (g) → co₂ (g) + 2h₂o (g) caco₃ (s) → cao (s) + co₂ (g) 2mg (s) + o₂ (g) → 2mgo (s) pbco₃ (s) → pbo + co₂

Explanation:

Step1: Recall decomposition reaction definition

A decomposition reaction is a reaction in which a single compound breaks down into two or more simpler substances.

Step2: Analyze each option

• For $CH_4(g)+2O_2(g)

ightarrow CO_2(g) + 2H_2O(g)$, it is a combustion reaction (a compound reacting with oxygen to produce carbon - dioxide and water).

• For $CaCO_3(s)

ightarrow CaO(s)+CO_2(g)$, a single compound ($CaCO_3$) breaks down into two simpler substances ($CaO$ and $CO_2$), which is a decomposition reaction.

• For $2Mg(s)+O_2(g)

ightarrow 2MgO(s)$, it is a combination reaction (two substances combining to form one compound).

• For $PbCO_3(s)

ightarrow PbO(s)+CO_2(g)$, a single compound ($PbCO_3$) breaks down into two simpler substances ($PbO$ and $CO_2$), which is a decomposition reaction.

Answer:

$CaCO_3(s)
ightarrow CaO(s)+CO_2(g)$ and $PbCO_3(s)
ightarrow PbO(s)+CO_2(g)$