Class 9 Practice Level 2 - Set 1 – Atoms and Molecules

Total questions: 25

What is the mass of one atom of carbon-12?

Topic: Basic Concepts of Atoms and Molecules

$ \displaystyle {1.66\text{ }\times \text{ }{{{10}}^{{-24}}}}$ g

$ \displaystyle {2.00\text{ }\times \text{ }{{{10}}^{{-23}}}}$ g

$ \displaystyle {1.99\text{ }\times \text{ }{{{10}}^{{-23}}}}$ g

$ \displaystyle {1.99\text{ }\times \text{ }{{{10}}^{{-24}}}}$ g

None

What is the relative atomic mass of an element?

Topic: Basic Concepts of Atoms and Molecules

The mass of an atom compared to 1/12th the mass of a carbon-12 atom

The mass of an atom compared to 1/16th the mass of an oxygen-16 atom

The mass of an atom compared to the mass of a hydrogen atom

The mass of an atom compared to the mass of a helium atom

None

What is the molecular mass of $ \displaystyle C{{O}_{2}}$?

Topic: Basic Concepts of Atoms and Molecules

28 g/mol

32 g/mol

44 g/mol

40 g/mol

None

According to the Law of Multiple Proportions, if two elements combine to form more than one compound, then the masses of one element that combine with a fixed mass of the other element are in the ratio of

Topic: Laws of Chemical Combination

Whole numbers

Fractions

Decimals

None of the above

None

Who discovered the Law of Definite Proportions?

Topic: Laws of Chemical Combination

John Dalton

Joseph Proust

Antoine Lavoisier

Robert Boyle

None

Which particle is not present in the nucleus of an atom?

Topic: Atomic Structure

Proton

Neutron

Electron

All of the above

None

What is the atomic number of an element with 11 protons and 12 neutrons?

Topic: Atomic Structure

None

Which scientist proposed the plum pudding model of the atom?

Topic: Atomic Structure

Niels Bohr

Ernest Rutherford

J.J. Thomson

James Chadwick

None

What is the difference between the isotopes of an element?

Topic: Isotopes

Number of protons

Number of neutrons

Number of electrons

Number of positrons

None

10.

Which isotope of hydrogen is used in nuclear fusion reactions?

Topic: Isotopes

Protium

Deuterium

Tritium

None of the above

None

11.

What is the volume occupied by 1 mole of any gas at standard temperature and pressure (STP)?

Topic: Mole Concept

22.4 L

24 L

22 L

23.5 L

None

12.

Calculate the number of moles in 88 grams of $ \displaystyle C{{O}_{2}}$?

Topic: Mole Concept

1 mole

2 moles

3 moles

4 moles

None

13.

What is the molecular mass of nitrogen dioxide ($ \displaystyle N{{O}_{2}}$)?

Topic: Molecular Mass and Mole Concept

38 g/mol

42 g/mol

46 g/mol

48 g/mol

None

14.

How many grams are there in 0.5 moles of sulphur dioxide ($ \displaystyle S{{O}_{2}}$)?

Topic: Molecular Mass and Mole Concept

32 g

48 g

40 g

32.5 g

None

15.

What is the empirical formula of a compound with a molecular formula of $ \displaystyle {{{C}_{2}}{{H}_{4}}}$?

Topic: Empirical and Molecular Formulas

$ \displaystyle {{C}{H}}$

$ \displaystyle {C{{H}_{2}}}$

$ \displaystyle {{{C}_{2}}{{H}_{2}}}$

$ \displaystyle {C{{H}_{3}}}$

None

16.

What is the molecular formula of a compound with an empirical formula of $ \displaystyle {C{{H}_{2}}}$ and a molar mass of 28 g/mol?

Topic: Empirical and Molecular Formulas

$ \displaystyle {{{C}_{2}}{{H}_{4}}}$

$ \displaystyle {C{{H}_{2}}}$

$ \displaystyle {{{C}_{3}}{{H}_{6}}}$

$ \displaystyle {{{C}_{4}}{{H}_{8}}}$

None

17.

How many moles are present in 40 g of He?

Topic: Chemical Reactions and Equations

10 moles

5 moles

20 moles

6 moles

None

18.

How many grams of water are produced when 2 moles of hydrogen react with 1 mole of oxygen?

Topic: Chemical Reactions and Equations

18 g

36 g

54 g

72 g

None

19.

An element has an atomic number of 17 and a mass number of 35. How many neutrons does it have?

Topic: Atomic Number and Mass Number

None

20.

Which element has an atomic number of 13?

Topic: Atomic Number and Mass Number

Magnesium

Silicon

Aluminium

Phosphorus

None

21.

Which element is represented by the symbol 'Fe'?

Topic: Periodic Table and Elements

Fluorine

Iron

Francium

Fermium

None

22.

What is the atomic number of Neon?

Topic: Periodic Table and Elements

None

23.

In the reaction $ \displaystyle CaC{{O}_{3}}+\text{ }2HCl\text{ }\to \text{ }CaC{{l}_{2}}+\text{ }{{H}_{2}}O\text{ }+\text{ }C{{O}_{2}}$, how many moles of $ \displaystyle C{{O}_{2}}$ are produced from 1 mole of $ \displaystyle CaC{{O}_{3}}$?

Topic: Stoichiometry

1 mole

2 moles

3 moles

4 moles

None

24.

How many moles of $ \displaystyle {{H}_{2}}O$ are produced when 2 moles of $\displaystyle C{{H}_{4}}$ react with 4 moles of $\displaystyle {{O}_{2}}$in the reaction $\displaystyle C{{H}_{4}}+\text{ }2{{O}_{2}}\to \text{ }C{{O}_{2}}+\text{ }2{{H}_{2}}O$ ?

Topic: Stoichiometry

2 moles

3 moles

4 moles

5 moles

None

25.

What is the empirical formula of a compound with a molecular formula of $ \displaystyle {{C}_{6}}{{H}_{{12}}}{{O}_{6}}$ ?

Topic: Empirical and Molecular Formulas

$ \displaystyle {CHO}$

$ \displaystyle {{{C}_{2}}{{H}_{4}}{{O}_{2}}}$

$\displaystyle {C{{H}_{2}}O}$

$\displaystyle {{{C}_{3}}{{H}_{6}}{{O}_{3}}}$

None

1 out of 25

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Class 9 Practice Level 2 - Set 1 – Atoms and Molecules

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