Question # 1

Which statement about an atom is true ?

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The number of neutrons is not equal to number of electrons

Mass number is less than atomic number

All the elements have only one mass number

Mass number can be equal to atomic number

Hemoglobin contains nearly:

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10,000 atoms

100 atoms

1000 atoms

1 atom

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99.2%

99.5%

90.5%

96.2%

Isotopes of an element differ in

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Number of protons

Number of electrons

Number of neutrons

Number of electrons and protons

The isotopes of an element

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Possess same mass number

Possess same number of protons

Do not possess same chemical properties

May or may not possess same chemical properties

The relative abundance of the ions with a definite m/e value is measured by

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High pressure of vapours

Strength of electric current measured

Quantity of fast moving electrons

Electron gas

The wave length of visible light is 500 nm. In S.I. unit this value is

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5 x 10^-8m

5 x 10^-9m

500 x 10^-7m

500 x 10^-9m

One mole of SO₂contains

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6.02 x 10²³atoms of oxygen

18.1 x 10²³, molecules of SO₂

6.02 x 10²³atoms of sulphur

4 gram atoms of SO₂

A compound contains one atom of oxygen and % of O 34.78, then molecular mass of compound is

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46

78

110

180

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32 g

3.2 g

5.6 g

9.6 g

A compound contains 75% carbon and 25% hydrogen, by mass. What is the molecular formula of the compound/

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C₃H₈

CH₄

C₂H₄

C₂H₆

The value of R(General Gas Constant) is

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8.3134 JK^-1mole^-1

1.987 Cal K^-1Mole^-1

Both a and b

1.987 JK^-1mole^-1

A species having positive or negative charge is called:

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Electron

Ion

Proton

Atom

The mass of sulphur which combines with 24 grams oxygen to form SO₂

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32 gram

24 gram

8 gram

12 gram

Ascorbic acid contains 40.92% carbon, 4.58%, hydrogen and 54.4% oxygen. The empirical formula is

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C₃H₄O₃

C₂H₄O₃

C₃H₅O₄

C₂H₃O₁

The empirical formula of a compound is CH₂O. What may be the compound

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C₂H₅OH

C₆H₅OH

HCOOH

The mass of one mole of proton is

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1.008 g

0.184 g

1.673 g

1.008 mg

1.12 dm³of N₂gas at S.T.P. has mass of N₂gas

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2.8 g

2.4 g

1.4 g

14 g

Metal tend to lose electrons, becoming:

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Metals

Positively charged

Negatively charged

(a)And (c)

X-ray work has shown that the diameters of atom are of the order of

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8 x 10^-10m

2 x 10^-10m

8 x 10^-8m

2 x 10^-8m

The relative abundance of Pb isotopes is 1.5% Pb²⁰⁴, 23.6% Pb²⁰⁶, 22.6% Pb²⁰⁷, 52.3% Pb²⁰⁸The relative atomic mass of Pb is

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207.94

208.24

206.94

207.24

Which one of the following step is not involved in determination of empirical formula

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Determination % of each element

Determination of gram atom of each element

Determination of isotopes of each element

Determination of atomic ratio of element

A beaker contains 9 grams of water. The number of H atoms is

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6.02 x 10²³

3.01 x 10²³

6.02 x 10²⁴

3.01 x 10²⁴

Benzene is stable to:

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Oxidation

Nitration

KMnO₄

SULPHONATION

Relative atomic mass of an element is the mass of the element relative to

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1/12 mass of carbon-12

1/12 mass of carbon

1 mass of hydrogen atom

1/16 mass of oxygen

The empirical formula of a liquid compound is known to be C₂H₄O. What other information is needed to work out its molecular formula?

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The percentage composition of the compound

The relative molecular mass of the compound

The density of the compound

The volume occupied by one mole of the compound

A compound having empirical formula C₃H₃O and its molecular mass is 110.02. Its molecular formula is

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C₃H₃O

C₆H₆O₂

C₉H₉O₃

C₃H₆O₂

When nitrogen is 5.6 grams in NO₂. then number of moles of NO₂is

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0.5

0.4

0.04

0.05

Molecules of High molecular weight usually greater than 10,000 are called:

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Macro molecules

Mega molecules

Poly molecules

Gega molecules

NH₃, HCL, H₂O, HL are:

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Diatomic molecules

Poly-atomic molecules

Mono-atomic molecules

Hetero atomic molecules

A balloon contains 0.02 gram of H₂gas, it contains H₂molecules

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6.02 x 10²³

3.01 x 10²²

6.02 x 10²¹

3.01 x 10²¹

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