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प्रश्न
A change in the physical state can be brought about
पर्याय
only when energy is given to the system
only when energy is taken out from the system
when energy is either given to or taken out from the system
without any energy change
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उत्तर
when energy is either given to or taken out from the system
When energy is given to the system the solid state changes to liquid. When energy is taken out from a liquid it changes to solid e.g., ice changes to water and water to water vapours when heat energy is given. Water vapours or steam condense to water and water freezes to ice when energy is decreased.
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संबंधित प्रश्न
Why is it not possible to see an atom with naked eyes?
TRUE \ FALSE
Neils Bohr gave the theory to explain the arrangement of protons in an atom.
ANSWER IN DETAIL
Enlist the features of Bohr’s model of an atom. How did he correct the Rutherford’s model ?
Write the names of the elements present in the:-
Acetic acid
Define: Chemical bond
Who originated the word ‘atom’ ?
Name the particle or particles you would expect to find in :
The orbit of an atom
A certain particle ‘X’ has 17 protons, 18 electrons and 20 neutrons.
What is the atomic numebr of X ?
Fill in the blank
A charged particle is called an _____
Dalton's atomic theory says that atoms are indivisible. Is this statement still valid ? Give reasons for your answer.
Which has more atoms, 50 g of aluminium or 50 g of iron ? Illustrate your answer with the help of calculations.
(Atomic masses : Al = 27 u ; Fe = 25 u)
Draw diagrams representing the atomic structures of the following:
- Sodium atom
- Chlorine ion
- Carbon atom
- Oxygen ion
Name the sub-atomic particles.
Define the following term with an example.
Metalloid
______ is the smallest particle of an element.
The volume occupied by 4.4 g of CO2 at S.T.P ______
Write any two observations which support the fact that atoms are divisible.
The smallest unit of an element is ______.
The most abundant type of atom is the universe is ______.
Atoms have a radius of the order ______.
