The formation of rust on the surface of iron is called __________ of iron.
rusting
melting
condensation
none of these
The chemical name of baking soda is
Sodium carbonate
Sodium hydrogen carbonate
Calcium phosphate
Calcium oxychloride
Burning of wood is a _________ change.
Physical
Chemical
Reversible
Temporary
Identify the substance that evaporates at room temperature:
Water
Oil
Kerosene
Ammonium chloride
When a solid directly turns into gaseous state, it is called:
Sublimation
Condensation
Polymerisation
Melting
A change in which a substance undergoes a change in its physical properties is called a ________ change.
Thermal
Thermodynamic
Chemical changes are
temporary
partial
permanent
A seed growing into a tree is an example of:
Slow physical change
Fast periodic change
Slow natural change
Man made reversible change
Cooking of rice is an example of:
Irreversible change
Endothermic reaction
Both A and B
None of these
When liquids are heated, they turn into gases. The yellow egg yolk present inside the egg is a liquid but when it is heated, it changes into an omelet which is solid, why?
Sometimes, liquids turn into solids
Omelet does not follow the above rule
Strictly speaking, the rule does not apply to complex mixtures and egg yolk is a complex mixture
The given statement is false
