Classify the sentences based on the chemical reactions they describe. synthesis decomposition replacement 1.when a clam shell (caco3) is heated, carbon dioxide (co2) is given off and a white powder, calcium oxide (cao), forms. 2.'nitrogen pentoxide (n2o5) is an unstable gas that changes to nitrogen dioxide (no2) and oxygen (o2) at room temperature. 3.sodium (na) reacts with chlorine (cl) to give sodium chloride (nacl). 4.zinc (zn) metal reacts with copper sulfate (cu2so4) to give zinc sulfate (znso4) and copper (cu). 5.a strip of magnesium (mg) burns brightly in oxygen (o2) to form a white powder, magnesium oxide (mgo). 6.on heating iron ore (fe2o3) with carbon (c), we get iron (fe) and carbon dioxide (co2).

1.When a clam shell (CaCO3) is heated,carbon dioxide (CO2) is given off and a white powder, calcium oxide (CaO), forms.
This is a decomposition reaction because calm shell CaCO3 is getting decomposed into other products.

2.'Nitrogen pentoxide (N2O5) is an unstable gas that changes to nitrogen dioxide (NO2) and oxygen (O2) at room temperature.
This is also a decomposition reaction as nitrogen pentaoxide is getting decomposed.

3.Sodium (Na) reacts with chlorine (Cl) to give sodium chloride (NaCl).
This is a synthesis reaction as two reactants are producing a product.

4.Zinc (Zn) metal reacts with copper sulfate (Cu2SO4) to give zinc
sulfate (ZnSO4) and copper (Cu).
This is a displacement reaction because Zn displaces Cu.

5.A strip of magnesium (Mg) burns brightly in oxygen (O2) to form a white powder, magnesium oxide (MgO).
This is a synthesis reaction because Mg and oxygen react to form magnesy oxide.

6.On heating iron ore (Fe2O3) with carbon (C), we get iron (Fe) and carbon dioxide (CO2).
This is a synthesis reaction because iron oxide reacts with carbon to produce Fe.