What is an atom?

2

(a)

Define atomic mass unit.

2

(a)

What are ionic compounds?

2

(a)

The chemical formula of chloride of metal 'M' is MCl.Write the chemical formula of its chloride, bicarbonate and sulphide.

2

(a)

Define 'Molecular Mass'

2

(a)

Define the term: Gram molecular mass. How is it related to the mole and Avogadro number?

2

(a)

How do you account for the fact that grame atomic mass or gram molecular mass of any substance contains the same number of particles?

2

(a)

The ratio of hydrogen and oxygen in water is 1:8 by mass, find out their ratio by number of atoms, in one molecule of water(Atomic mass: H = 1u, O=16u)

2

(a)

Calculate the molecular mass of the following
(i) HNO₃ (ii) CH₃COOH

2

(a)

Calculate the number of atoms in one grame of zinc (atomic mass of zinc is 65.37).Give the weight of 1 atom of zinc.

2

(a)

16.26 mg of a sample of an element 'X' contains 1.66 x 10²⁰ atoms.What is the atomic mass of the element X? 

2

(a)

A 0.24 g sample of compound of oxygen and boron was found by analysis to contain 0.096 g of boron and 0.144 g of oxygen.Calculate the percentage composition of the compound by weight.

2

(a)

Calculate the number of molecules of sulphur (S₈) present in 16 g of solid sulphur.

2

(a)

During the formation of ammonia, what mass of hydrogen gas would be required to react completely with 42 g of nitrogen gas?

2

(a)

The most remarkable feature of Dalton's atomic theory was that of atomic mass.Since determining atomic mass of an individual atom was a difficult task, the relative atomic, masses were determined using the laws of chemical combinations and the compounds formed.In 1961, carbon-12 isotope was chosen as the standard reference for measuring atomic masses.It says that one atomic mass unit is a mass unit equal to exactly 1/12th the mass of one atom of carbon-12 Since experimentally t was observed that 3g cabon-12 combines with 4g of oxygen to form CO, further 4g sulphur combines with 4g oxygen to form SO₂
(a) Calculate the atomic mass of sulphur.
(b) How was the concept of relative masses utilized in olden times?Was it successful?

2

(a)