Classify the sentences based on the chemical reactions they describe.
When a clam shell (CaCO3)
is heated, carbon dioxide
(CO2) is given off and a
white powder, calcium
oxide (CaO), forms.>
Nitrogen pentoxide
(N2O5) is an unstable
gas that changes to
nitrogen dioxide (NO2)
and oxygen (O2) at
room temperature.

Sodium (Na) reacts with
chlorine (Cl) to give
sodium chloride (NaCl).
Zinc (Zn) metal reacts
with copper sulfate
(Cu2SO4) to give zinc
sulfate (ZnSO4) and
copper (Cu).
A strip of magnesium (Mg)
burns brightly in
oxygen (O2) to form
a white powder,
magnesium oxide (MgO).
On heating iron ore
(Fe2O3) with carbon (C),
we get iron (Fe) and
carbon dioxide (CO2).