Question

detecting combination reactions
from your work on the previous screen, you saw that combination reactions follow the general pattern ( a + b
ightarrow ab ).
based on this, which of the reactions below are combination reactions?
( fe(s)+s(s)
ightarrow fes(s) )
( mgo(s)+co_{2}(g)
ightarrow mgco_{3}(s) )
( cao(s)+h_{2}o(l)
ightarrow ca(oh)_{2}(aq) )
( h_{2}so_{3}(aq)
ightarrow h_{2}o(l)+so_{2}(g) )

Explanation:

Combination reactions follow the general pattern \(A + B \to AB\).

• For \(Fe(s)+S(s)\to FeS(s)\), two reactants (\(Fe\) and \(S\)) combine to form one product (\(FeS\)).
• For \(MgO(s)+CO_{2}(g)\to MgCO_{3}(s)\), two reactants (\(MgO\) and \(CO_{2}\)) combine to form one product (\(MgCO_{3}\)).
• For \(CaO(s)+H_{2}O(l)\to Ca(OH)_{2}(aq)\), two reactants (\(CaO\) and \(H_{2}O\)) combine to form one product (\(Ca(OH)_{2}\)).
• For \(H_{2}SO_{3}(aq)\to H_{2}O(l)+SO_{2}(g)\), one reactant (\(H_{2}SO_{3}\)) breaks down into two products (\(H_{2}O\) and \(SO_{2}\)), which is a decomposition reaction.

Answer:

\(Fe(s)+S(s)\to FeS(s)\), \(MgO(s)+CO_{2}(g)\to MgCO_{3}(s)\), \(CaO(s)+H_{2}O(l)\to Ca(OH)_{2}(aq)\)