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

Which one of the following compounds does not have the empirical formula CH₂O?

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Ethanoic acid, CH₃CO₂H

Ethanol, CH₃CH₂OH

Glucose, C₆H₁₂O₆

Methanal, HCHO

Covalent compound s mostly exist in the form of:

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Protons

Atoms

Neutrons

Molecules

A compound X contains 50% sulphur and 50% oxygen by mass. What is the empirical formula of compound X?

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SO

SO₂

SO₃

SO₄

Which of the following statements is not true?

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Isotopes with even atomic masses are comparatively abundant

Isotopes with even atomic masses and even atomic numbers are comparatively abundant

Isotopes with even atomic masses and odd atomic number are comparatively abundant

The branch of science dealing with structure, composition and changes in matter and laws and principles which govern these changes is called as

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chesmistry

Geology

Physics

Mechanics

The quantitative relationship between the substances according to balanced equation describes

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Reversible reactions

Stoichiometry

Limiting reacting

Percentage composition

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

Where energy is released during a reaction it is

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Exothermic reaction

Endothermic reaction

A free radical reaction

A bond breaking reaction

Isotopes of an element differ in

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Number of protons

Number of electrons

Number of neutrons

Number of electrons and protons

When an electron is added to a uni positive ion we get:

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Cation

Molecule

Neutral atom

Anion

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99.2%

99.5%

90.5%

96.2%

A limiting reactant is the one which

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Is taken in lesser quantity in grams as compared to other reactants

Is taken in lesser quantity in volume as compared to other reactants

Gives the maximum amount of the product which is required

Gives the minimum amount of the product under consideration

The phenomenon of isotropy was first discovered by

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Soddy

Rutherford

Bohr

Dalton

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0 dm³

3 dm³

2 dm³

3 dm³

Matter is defined as any thing which occupies space and:

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Molecules

Mass

Compound

Molecules

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84.84 %

89.89%

81.81%

90.90%

A molecule of haemoglobin is made up if nearly

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10,000 atoms

50,000 atoms

2500 atoms

1500 atoms

Who one mole of each of the following is completely burned in oxygen, which gives the largest mass of carbon dioxide?

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Carbon monoxide

Diamond

Ethane

Methane

Which of the sub-atomic particles is not charged

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Electron

Proton

Neutron

All of them

The number of moles of CO2which contain 8.0 g of oxygen

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0.25

0.50

1.0

1.50

Hemoglobin contains nearly:

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10,000 atoms

100 atoms

1000 atoms

1 atom

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

0.5 mole of CH₄and 0.5 mole of SO₂gases have equal

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Volume

Mass is gram

Total number of atoms

Number of molecules

An ion bearing positive charge is called:

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Cation

Positron

Anion

None of above

He Ar and Ne are:

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Mono-atomic molecules

Hetero atomic molecules

Poly-atomic molecules

Diatomic molecules

The atom of an element is

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The smallest particle

The fundamental particle

The independent particle

The charged particle

Atoms and molecules can either gain or lose electrons, forming charge particles called:

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Positrons

Photons

Ions

Electrons

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

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 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

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