which of these are chemical change - iron rusting
- magnesium burning
- a lump os sodium carbonate is being crushed
- carbon being burned with oxygen to give co2
- burning of petroll
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1) Rusting of iron is a chemical change. This is because rust is produced when iron reacts with the oxygen in the atmosphere, thus producing iron oxide.
Fe + xH2O + O2 Fe2O3.xH2O
2) Burning of magnesium in air is a chemical reaction. On heating , Mg metal burns in air giving intense heat and light to form a basic oxide called magnesium oxide.
2Mg + O2 2MgO
3) Crushing of lump of sodium carbonate is a physical change.
4) Burning of carbon in Oxygen is a chemical change as new compound is formed, that is , CO2.
C + O2 CO2
5) Burning of petrol is also a chemical change.
Fe + xH2O + O2 Fe2O3.xH2O
2) Burning of magnesium in air is a chemical reaction. On heating , Mg metal burns in air giving intense heat and light to form a basic oxide called magnesium oxide.
2Mg + O2 2MgO
3) Crushing of lump of sodium carbonate is a physical change.
4) Burning of carbon in Oxygen is a chemical change as new compound is formed, that is , CO2.
C + O2 CO2
5) Burning of petrol is also a chemical change.