Question

having read about the different kinds of chemical equations, jameel decided to learn more about how they work. read each of the descriptions or equations that describe the different kinds of chemical reactions that can occur. drag each one into the correct box.
2ki + pb(no3)2 → pbl2 + 2kno3
two or more elements or compounds combine to make a more complex substance
compounds break down into simpler products
2h2o2 → 2h2o + o2
two elements in different compounds trade places
2mg + o2 → 2 mgo
decomposition replacement synthesis

Explanation:

• For the equation \(2KI + Pb(NO_3)_2

ightarrow PbI_2 + 2KNO_3\), two elements (\(I\) and \(NO_3\)) in different compounds trade places, so it is a replacement reaction.

• The description “two or more elements or compounds combine to make a more complex substance” matches the definition of a synthesis reaction. The equation \(2Mg + O_2

ightarrow 2MgO\) (where \(Mg\) and \(O_2\) combine to form \(MgO\)) also fits the synthesis reaction.

• The description “compounds break down into simpler products” is the definition of a decomposition reaction. The equation \(2H_2O_2

ightarrow 2H_2O + O_2\) (where \(H_2O_2\) breaks down into \(H_2O\) and \(O_2\)) is a decomposition reaction.

Answer:

• Decomposition: “compounds break down into simpler products”, \(2H_2O_2

ightarrow 2H_2O + O_2\)

• Replacement: \(2KI + Pb(NO_3)_2

ightarrow PbI_2 + 2KNO_3\), “two elements in different compounds trade places”

• Synthesis: “two or more elements or compounds combine to make a more complex substance”, \(2Mg + O_2

ightarrow 2MgO\)