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Physical Change. Chemical Change. OR. ??. PHYSICAL. H 2 O (s) H 2 O (l). CHEMICAL. light. 6CO 2 (g) +6H 2 O (l) C 6 H 12 O 6 ( aq ) + 6O 2 (g). PHYSICAL. KMnO 4 (s) K + ( aq ) + MnO 4 - ( aq ). Hydrocarbons + O 2 CO 2 + H 2 O. CHEMICAL. CHEMICAL.
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Physical Change Chemical Change OR ??
PHYSICAL H2O (s) H2O (l)
CHEMICAL light 6CO2 (g)+6H2O (l) C6H12O6 (aq)+ 6O2 (g)
PHYSICAL KMnO4 (s) K+ (aq) + MnO4- (aq)
Hydrocarbons + O2 CO2 + H2O CHEMICAL
H2O (l) H2O (g) PHYSICAL
CHEMICAL 4Fe (s) + 3O2 (g) 2Fe2O3 (s)
PHYSICAL CO2 (s) CO2 (g)
CHEMICAL CaCO3 (s) + 2HCl(aq) CaCl2 (aq) + H2CO3 (aq)
How do we know a chemical reaction has occurred? • Heat or light is produced or absorbed • Gas evolved • The change is (generally) difficult to reverse • Change in colour* • Precipitate formed