A mole does not signify

1

(a)

atomic mass unit

(b)

6.023 x 10²³ ions

(c)

22.4 litres of a gas at STP

(d)

gram molecular mass

Which one of the following dose not represnt molar mass of a substance?

1

(a)

1 mole of HCl

(b)

6.023 x 10²³ molecules of helium

(c)

16 g of O₂

(d)

44 g of CO₂

One atomic mass unit is equal to weight of

1

(a)

one atom of hydrogen

(b)

\(\frac { 1 }{ 16 } \) th of oxygen atom

(c)

\(\frac { 1 }{ 12 } \) th of natural carbon atom

(d)

\(\frac { 1 }{ 12 } \) of C-12 isotopes of carbon

In SO₂, the mass of sulphur in combination with 3.0 oxygen is 

1

(a)

3.0 g

(b)

4.0 g

(c)

32.0 g

(d)

16.0 g

Which of the following supports Dalton's atomic theory of matter?

1

(a)

Formation of isotopes

(b)

Formation of isobars

(c)

Law of definite proportions

(d)

Graphite and diamond though made from carbon, show different properties.

Choose the correct statement

1

(a)

Two atoms of hydrogen combine with one atom of oxygen to give water molecule.

(b)

One atom of hydrogen combine with one atom of chlorine to from hydrogen chloride 

(c)

One atom of nitrogen combine with 3 atoms of hydrogen to form 1 molecule of ammonia

(d)

One atom of carbon combines with one molecules of oxygen to form one molecule of carbon dioxide.

Arrange the following compounds in the order of increasing number of molecules:
2 g NH₃; 2 g H₂O; 2 g CO; 2 g HCl

1

(a)

CO<HCl<H₂O<NH₃

(b)

HCl<CO<H₂O<NH₃

(c)

NH₃<H₂O<CO<HCl

(d)

NH₃<H₂O<CO<HCl

The unit of atomic mass is .............

1

(a)

u

Dalton's atomic theory provides explanation for the various laws of ...................

1

(a)

combinations

Naturally occurring oxygen is a mixture of atoms of slightly different masses called ............

1

(a)

isotopes

Avogadro's number represents ................... particles of a substance.

1

(a)

6.022 x 10²³

The abbreviations used for the lengthy names of elements are termed ............

1

(a)

symbols

One mole of sodium sulphate contains ............... atoms of sodium

1

(a)

12.046 x 10²³

Isotopes differ from each other in ............

1

(a)

molar mass

Law of ............. says that hydrogen and oxygen combine in the ratio 1 : 8 to form water.

1

(a)

definite proportions

(i) One mole of carbon atom weighs 12 g.Find the mass in grams of one atom of carbon (Given C = 12u, No = 6.022 x 10²³ per mole)
(ii) Calculate the mass of the following:
(a) 0.5 mole of N2 gas
(b) 0.2 mole of O-atoms
(c) 4 moles of aluminium atom
[Given, N = 14 u, 0 = 16 u, Al = 27 u,
Avogadro's number = 6.022 x 10²³ per mole ]

3

(a)

(i) Convert into mole 20 g of water (Atomic mass of hydrogen and oxygen are 1 and 16 respectively).
(ii) Convert into mole 22 g of carbon dioxide.

3

(a)

50 g 0f 10% lead nitrate is mixed with 50g of 10% sodium chloride in a closed vessel.After reaction has taken place, it was found that 6.83 g of lead chloride was precipated.Besides, the reaction mixture contained 90g water and sodium nitrate.Calculate the amount of sodium nitrate formed. 

3

(a)

Which postulate of Dalton's atomic theory is the result of the law of conservation of mass?

3

(a)

How were the names of elements derived?

3

(a)

Write the names of the compounds represented by the following formulae.
(i) NaBr (ii) Al₂O₃ (iii) ZnNO₃ (iv) HCl (v) NaCl (vi) CaCO₃

4

(a)