ECAT Pre Engineering Chemistry Chapter 1 MCQ Test With Answer

Which of the following statement is correct for a chemical reaction to occur molecules of substances must

• Collide with each other A
• Collide with energy more than activation energy B
• Collide with energy less than activation energy C
• Collide with high frequency 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

Isotopes of an element differ in

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

The number of moles of CO2which contain 8.0 g of oxygen

• 0.25 A
• 0.50 B
• 1.0 C
• 1.50 D

An ion bearing positive charge is called:

• Cation A
• Positron B
• Anion C
• None of above D

Which one of the following statements is not correct

• A molecule is the smallest particle of an element which can exist independently A
• He is a molecule of helium B
• S₈is a molecule of sulphur C
• O₃is a molecule of oxygen 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

The volume occupied by 1.4 g of N₂ at S.T.P is

• 2.24 dm³ A
• 22.4 dm³ B
• 1.12 dm³ C
• 112 cm³ 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

A ring contains 3 gram diamond. The number of C-atoms which a ring contains is

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

• 84.84 % A
• 89.89% B
• 81.81% C
• 90.90% D

0.5 mole of CH₄and 0.5 mole of SO₂gases have equal

• Volume A
• Mass is gram B
• Total number of atoms C
• Number of molecules D

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

• The percentage composition of the compound A
• The relative molecular mass of the compound B
• The density of the compound C
• The volume occupied by one mole of the compound D

Determination of atomic masses and invention of system of writing symbols was made by:

• J. Berzelius A
• Democritus B
• Dalton C
• None of above D

Macromolecules are

• organic molecules A
• High molecular mass molecules B
• Natural compounds C
• Rarely occurring molecules D

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

• chesmistry A
• Geology B
• Physics C
• Mechanics D

First atomic theory was put forward by an English school teacher:

• Maxewell A
• Newton B
• Sanger C
• John Dalton D

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

• C₃H₄O₃ A
• C₂H₄O₃ B
• C₃H₅O₄ C
• C₂H₃O₁ D

If four moles of sulpur dioxide are oxidised to sulphur trioxide, how many moles of oxygen molecules are required

• 0.5 A
• 1.0 B
• 1.5 C
• 2.0 D

Which of the sub-atomic particles is not charged

• Electron A
• Proton B
• Neutron C
• All of them D

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

• 2.8 g A
• 2.4 g B
• 1.4 g C
• 14 g 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

Smallest particle of an element which may or may not have independent existence is known as:

• A molecule A
• An ion B
• An atom C
• An electron D

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

• C₃H₈ A
• CH₄ B
• C₂H₄ C
• C₂H₆ D

• 32 g A
• 3.2 g B
• 5.6 g C
• 9.6 g D

Isotopes differ in

• properties which depend upon mass A
• arrangement of electrons in orbitals B
• chemical properties C
• the extent to which they may be affected in electric fields D

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

• C₂H₅OH A
• C₆H₅OH B
• HCOOH C
• 
  D

Metal tend to lose electrons, becoming:

• Metals

  A

• Positively charged

  B

• Negatively charged

  C

• (a)And (c)

  D

• 99.2% A
• 99.5% B
• 90.5% C
• 96.2% D

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

• 1/12 mass of carbon-12 A
• 1/12 mass of carbon B
• 1 mass of hydrogen atom C
• 1/16 mass of oxygen D