ECAT Pre Engineering Chemistry Chapter 1 MCQ Test With Answer

The isotopes of an element

• Possess same mass number A
• Possess same number of protons B
• Do not possess same chemical properties C
• May or may not possess same chemical properties D

CL₂, N₂ and O_{2 are:}

• Diatomic molecules

  A

• Hetero atomic molecules

  B

• Poly-atomic molecules

  C
• Mono-atomic molecules D

• 0 dm³ A
• 3 dm³ B
• 2 dm³ C
• 3 dm³ D

A balloon contains 0.02 gram of H₂gas, it contains H₂molecules

• 6.02 x 10²³ A
• 3.01 x 10²² B
• 6.02 x 10²¹ C
• 3.01 x 10²¹ D

Which statement about molecule is incorrect ?

• Molecules of a substance are similar A
• Hemoglobin is a homo atomic molecules B
• Oxygen molecule is a macro molecule C
• It exist independently D

• 
  A
• 
  B
• 
  C
• 
  D

Two different hydrocarbon each contain the same percentage by mass of hydrogen. It follows that they have the same

• Empirical formula A
• Number of atoms in a molecules B
• Number of isomers C
• Relative molecular mass D

What is the volume in cm³of 3.01 x 10²³molecules of O₂gas at S.T.P

• 1000 cm³ A
• 11000 cm³ B
• 1120 cm³ C
• 11200 cm³ D

Which of the following statements is not true?

• Isotopes with even atomic masses are comparatively abundant A
• Isotopes with even atomic masses are comparatively abundant B
• Isotopes with even atomic masses and even atomic numbers are comparatively abundant C
• Isotopes with even atomic masses and odd atomic number are comparatively abundant D

The negatively charged particles are called

• Cation A
• Radical B
• Anion C
• Positron D

One mole of ethanol and one mole of ethane have an equal

• Mass A
• Number of atoms B
• Number of electrons C
• Number of molecules D

The phenomenon of isotropy was first discovered by

• Soddy A
• Rutherford B
• Bohr C
• Dalton D

The relative atomic mass of chlorine is 35.5. What is the mass of 2 mol of chlorine gas

• 142 g A
• 71 g B
• 35.5 g C
• 18.75 g D

C₆H₁₂O₆and C₁₂H₂₂O₁₁ are:

• Mono-atomic molecules A
• Diatomic molecules B
• Poly-atomic molecules C

• Hetero atomic molecules

  D

A limiting reactant is one which according to the stoichiometric equation

• Has excess mass A
• Has least mass B
• Has excess number of moles C
• Has least number of moles D

The pressure of vapours when sent to the ionization chamber in mass spectrometer is

• 10^-5to 10^-6torr A
• 10^-6to 10^-7torr B
• 10^-7to 10^-8torr C
• 10^-3to 10^-4torr D

Objects of the size of an atom can be observed in

• An electron microscope A
• An x-ray spectrum B
• Atomic absorption spectrum C
• A visible spectrum D

Which of the following compounds contains the highest percentage by mass of nitrogen?

• Ammonia, NH₃ A
• Ammonium carbamate, NH₂CO₂NH₄ B
• Ammonium carbonate, (NH₄)₂CO₃ C
• Hydrazine, N₂H₄ D

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

• Macro molecules A
• Mega molecules B
• Poly molecules C
• Gega molecules D

Isotopes of an element differ in

• Number of protons A
• Number of electrons B
• Number of neutrons C
• Number of electrons and protons D

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

• Cation A
• Molecule B
• Neutral atom C
• Anion D

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

• 6.02 x 10²³ A
• 3.01 x 10²³ B
• 6.02 x 10²⁴ C
• 3.01 x 10²⁴ D

• 300 cm³ A
• 200 cm³ B
• 150 cm³ C
• 100 cm³ D

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

• SO A
• SO₂ B
• SO₃ C
• SO₄ D

What is the maximum mass of aluminium which can be obtained from 240g of aluminium oxide Al₂O₃?

• 26 g A
• 127 g B
• 51 g C
• 108 g D

In molecules kinetic and potential energies are:

• Definite A
• Moderate B
• Indefinite C
• None of above D

The largest number of molecules are present in

• 3.6 g of H₂O A
• 4.8 g of C₂H₅OH B
• 2.8 g of CO C
• 5.4 g of N₂O₅ D

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

• C₂H₅OH A
• C₆H₅OH B
• HCOOH C
• 
  D

Matter is defined as any thing which occupies space and:

• Molecules A
• Mass B
• Compound C
• Molecules D

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

• C₃H₃O A
• C₆H₆O₂ B
• C₉H₉O₃ C
• C₃H₆O₂ D