Tag: atoms, molecules and chemical reactions

Questions Related to atoms, molecules and chemical reactions

Which of the following is a limitation of the law of constant composition is not applicable?

chemistry atoms, molecules and chemical reactions law of constant proportion - i law of constant proportion law of definite proportions

  1. When same isotopes of an element take part in the formation of a particular compounds.

  2. When different isotopes of different elements take part in the formation of a particular compound.

  3. When different isotopes of an element take part in the formation of a particular compound.

  4. None of the above.

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Correct Option: C
Explanation:
Law of constant composition is not applicable if an element exists in different isotopes which may be involved in the formation of the compound. The elements may combine in the same ratio but the compounds formed may be different.

Hence, the correct option is $(C)$
Assertion (A): Pure water obtained from different sources such as a river, well, spring, the sea always contains hydrogen and oxygen in the ratio of 1:8 by mass.

Reason (R): The total mass of reactants and products during chemical or physical change is always the same.
chemistry atoms, molecules and chemical reactions law of constant proportion - i law of constant proportion law of definite proportions

  1. Both A and R are true and R is the correct explanation of A

  2. Both A and R are true and R is not correct explanation of A

  3. A is correct and R is incorrect

  4. A is incorrect and R is correct

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Correct Option: A

Statement: Every nine parts of water by weight contain eight parts by weight of oxygen. 


State whether the given statement is true or false.

chemistry atoms, molecules and chemical reactions law of constant proportion - i law of constant proportion law of definite proportions

  1. True

  2. False

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Correct Option: A