Class 10 ncert science chemistry chapter 1 chemical reactionsandequations, types of chemical reactions class notes , class 10 board cbse.

NOTES



C H A P T ER 1 .
CHEMICAL REACTIONS AND EQUATIONS.

● O B S ER V A T I O N T O D E T ER M I N E A C H E M I C A L R E A C T I O N :
▪︎ C H A N G E I N S T A T E ( S O L I D , L I Q U I D , G A S A N D A Q U E O U S )
▪︎ C H A N G E I N CO L O R
▪︎ E V O L U T I O N O F G A S
▪︎ C H A N G E I N T E M P ER A T U R E ( B E A K ER B E CO M E S W A R M )
▪︎ FO R M A T I O N O F P R E C I P I T A T E
● T H E S E C H A N G E S C A N B E S E E N A F T ER A C H E M I C A L R E A C T I O N .
● TYPES OF CHEMICAL REACTIONS:
T H ER E A R E 5 T Y P E S O F C H E M I C A L R E A C T I O N S :
● CO M B I N A T I O N R E A C T I O N .
● D E CO M P O S I T I O N R E A C T I O N .
● DISPLACEMENT REACTION.
● DOUBLE DISPLACEMENT REACTION.
● O X I D A T I O N A N D R ED U C T I O N .

, COMBINATION REACTION.

A REACTION IN WHICH TWO OR MORE ELEMENTS OR COMPOUNDS COMBINE TO
FORM A SINGLE PRODUCT IS CALLED A COMBINATION REACTION.
FORMULA:
▪︎
CAO(S) + H₂O(L) ---- CA(OH)₂(AQ) + HEAT (ALREADY EXPLAINED IN
ACTIVITIES PDF)
▪︎
BURNING OF COAL:
C(S) + O₂(G) ---- CO₂(G)
▪︎
FORMATION OF WATER:
2H₂(G) + O₂(G) ---- 2H₂O(L).

DECOMPOSITION REACTION.

● A REACTION IN WHICH A SINGLE SUBSTANCE BREAKS INTO TWO OR MORE
SUBSTANCES IS CALLED A DECOMPOSITION REACTION.
● IF A DECOMPOSITION REACTION TAKES PLACE IN THE PRESENCE OF HEAT,
IT IS CALLED A THERMAL DECOMPOSITION REACTION.
● IF A DECOMPOSITION REACTION TAKES PLACE IN THE PRESENCE OF LIGHT,
IT IS CALLED A PHOTOLYTIC, PHOTOCHEMICAL, OR PHOTODECOMPOSITION
REACTION.
●
IF A DECOMPOSITION REACTION TAKES PLACE IN THE PRESENCE OF
ELECTRICITY, THEN THE TYPE OF REACTION IS KNOWN AS AN ELECTROLYTIC
DECOMPOSITION REACTION.
FORMULA:
▪︎
2FESO4(S) --HEAT-- FE2O3(S) + SO2(G) + SO3(G) (ALREADY EXPLAINED IN
ACTIVITIES PDF)
▪︎
2PB(NO3)2(S) --HEAT-- 2PBO(S) + 4NO3(G) + O2(G) ( ALREADY EXPLAINED IN
ACTIVITIES PDF)
▪︎
2AGCL(S) --SUNLIGHT-- 2AG(S) + CL2(G) ( ALREADY EXPLAINED IN
ACTIVITIES PDF)
▪︎
2AGBR(S) --SUNLIGHT-- 2AG(S) + BR2(G) (SIMILAR AS ABOVE REACTION)
THESE REACTIONS ARE USED IN BLACK AND WHITE PHOTOGRAPHY.
▪︎
CACO3(S) --HEAT-- CAO(S) + CO2(G)
IN THIS REACTION CALCIUM CARBONATE DECOMPOSES IN THE PRESENCE OF
HEAT TO FORM CALCIUM OXIDE AND CARBON DIOXIDE GAS.
THIS REACTION IS USED IN MANUFACTURING OF CEMENT.