Question

1. atomic mass does not have any units . why? 2. what is difference between molecular mass and actual mass of a molecule? 3. write the name and formula of one monoatomic and one polyatomic ion? 4. the relative mass of chlorine is 35.5.what do you understand by it? 5. an element forms an oxide M2O3. what will be the formula of its sulphate? 6.a chemical eqution must be balanced to satisfy whichlaw? state the law. 7.explain why the no. of atoms in one mole of hydrogen gas is double the no. of atoms in one mole of helium? 8. what is meant by variable valency ? give at least two examples showing variable valency? 9. which postulate of dalton's theory is the basis of law of conservation of mass? 10. which of the following molecules are tetra atomuc and which are penta atomic? CH3OH, CH4, H2O2, P4 &PCl5

Answer 1

• Molecular weight is the mass of one molecule while a molar mass is regarded as the mass of one mole.

It comprises of 6.023 *10 ^23 molecules.

• Nominal mass of water molecule is about 18. 1.

Mole is considered to be Avagadro number comprising of 6.023*10^23 molecules.

• Law of conservation states that the energy can neither be created nor be destroyed

Answer 2

HEY!!

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 1. Atomic mass is unitless because it is the ratio between the mass of an atom of a particular substance to that of 1 Carbon-12 atom and in this process, units cancel each other.

3. One monoatomic ion is Sodium (Na+) and a polyatomic ion is Hydroxyl (OH-)

4. By the given statement, we mean that one atom of Chlorine is 35.5 times heavier than an atom of C-12 atom.

5. M2(SO4)3

6. Law of conservation of mass.

This law is as follows-Atoms can neither can be created nor be destryed in a chemical reaction.

8. Variable valency means more than 1 valency.

Copper and Iron have variable valency.

9. Atoms are indivisible and can neither be created nor be destroyed in a chemical reaction.

10. Tetra atomic- H2O2, P4

   penta atomic- CH4