Select the correct answer from the choice in bracket to complete each sentence.
A change in which a substance retains its identity is a — [physical/chemical] change

Select the correct answer from the choice in bracket to complete each sentence. Dissolution of lead nitrate in water is deemed as a - [physical/chemical] change.

Select the correct answer from the choice in bracket to complete each sentence. A change in which matter undergoes a change but the total mass of substance is unaltered is a - [physical/ chemical] change.

Select the correct answer from the choice in bracket to complete each sentence:- An element Z with zero valency is a — [metal/noble gas/non-metal].

Select the correct answer from the choice in bracket to complete each sentence. Matter is added or removed during a - [chemical/physical] change

Select the correct answer from the choice in bracket to complete each sentence:- A- [proton/neutron] is a sub-atomic particle with no charge and unit mass.

Select the correct answer from the choice in bracket to complete each sentence: An example of a monoatomic molecule is _______ [hydrogen/helium).

Select the correct answer from the choice in bracket to complete each sentence. Energy required for completion of a physical change is - [released/absorbed] when the change is reversed.

Select the correct answer from the choice in bracket to complete each sentence: The reactive element from the two monoatomic elements is _______ [neon/silicon].

Select the correct answer from the choice in bracket to complete each sentence: The gas which has now replaced hydrogen in air balloons is _____________[argon, helium, neon].

Select the correct answer from the choice in bracket to complete each sentence: A soluble solid is separated from an insoluble solid by ________ [fractional crystallisation/ solvent extraction]