The chemical name of baking soda is
Sodium carbonate
Sodium hydrogen carbonate
Calcium phosphate
Calcium oxychloride
Chemical changes are
temporary
partial
permanent
none of these
________ protects us from the harmful ultraviolet radiation.
Oxygen
Hydrogen
Fluorine
Ozone
Properties such as shape,size,colour and state of a substance are called its ________ properties.
Physical
Chemical
Thermal
Thermodynamic
__________ turns lime water milky.
Carbondioxide
Carbonmonoxide
Rusting of iron is a chemical change because:
It is temporary
It can be cleaned and the original substance recovered
It is a slow reaction
A new substance is formed
Burning of any substance is a _________ change.
Temporary
Reversible
A change in which a substance undergoes a change in its physical properties is called a ________ change.
Dissolving salt in water is a/an:
Endothermic change
Exothermic change
Both A and B
Chemical combination
The cells used in a wrist watch undergo:
Physical change
Periodic change
Chemical change
None of these
