What is/are the identification characteristic/s of chemical changes?
a) color change
b) emission of a gas
c) formation of precipitate
d) all of these
What is/are the identification characteristic/s of chemical changes?
a) temperature change
b) odour change
c) new mixture forms
d) both a and b
Why apple turns brown after cutting?
a) decomposition started by bacteria
b) formation of iron oxide
c) formation of acids and salts
d) all of these
What is the color of Fe2+?
a) light blue
b) light green
c) light yellow brown
d) dark red
What is the
color of Fe3+?
a) light blue
b) light green
c) yellow brown
d) dark red
Which of the following reaction occurs when iron in apple converted into iron oxide in the presence of oxygen?
a) combustion
b) decomposition
c) oxidation
d) substitution
