Question

1- which of these is an Irreversible physical change?
a) rusting of iron
b) freezing of water
c) a double decomposition reaction
d) breaking of a glass tumbler

2- and arrow pointing downwards in a chemical reaction shows
a)evolution of gas
b) formation of precipitate
c) oxidant
d)displacement

3- a chemical reaction in which heat is given out is called
a) exothermic reaction
b) endothermic reaction
c) decomposition reaction
d) neutralization reaction ​

Answer 1

Answer:

1.c) a double decomposition reaction

2.d)displacement

3.a) exothermic reaction

Answer 2

Answer:

1. d. breaking of a glass tumbler

2. b. formation of precipitate

3. a. exothermic reaction