ECAT Pre Engineering Chemistry Chapter 1 MCQ Test With Answer

Isotopes of an element differ in

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

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

Matter is defined as any thing which occupies space and:

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

One mole of SO₂contains

• 6.02 x 10²³atoms of oxygen A
• 18.1 x 10²³, molecules of SO₂ B
• 6.02 x 10²³ atoms of sulphur C
• 4 gram atoms of SO₂ D

A species having positive or negative charge is called:

• Electron A
• Ion B
• Proton C
• Atom D

0.5 mole of CH4and 0.5 mole of SO2gases have equal

• Volume A
• Mass in grams B
• Total number of atoms C
• Number of molecules D

The phenomenon of isotropy was first discovered by

• Soddy A
• Rutherford B
• Bohr C
• Dalton 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

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

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

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 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

The percentage of H is the highest in

• CH₄ A
• NH₃ B
• H₂SO₄ C
• C₆H₁₂O₆ 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

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

• Determination % of each element A
• Determination of gram atom of each element B
• Determination of isotopes of each element C
• Determination of atomic ratio of element 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

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

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

Each molecule of haemoglobin is 68000 times heavier than one atom of

• C A
• H B
• N C
• O D

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

The number of subatomic particles in atoms sidcovered is more than:

• 110 A
• 100 B
• 125 C
• 90 D

The diameter of atoms is of the order:

• 2* 10^-5m A

• 2* 10^-10 m

  B
• 2* 10^-2m C
• 2* 10^-3m 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

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

• Ethanoic acid, CH₃CO₂H A
• Ethanol, CH₃CH₂OH B
• Glucose, C₆H₁₂O₆ C
• Methanal, HCHO D

In molecules kinetic and potential energies are:

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

Al³⁺is a symbol for aluminium

• Atom A
• Ion B
• Cation C
• Anion D

How many moles of oxygen, O₂are needed for the complete combustion of two moles of butane C₄H₁₀?

• 2 A
• 8 B
• 10 C
• 13 D

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

• 46 A
• 78 B
• 110 C
• 180 D

The number of isotopes of gold is

• 3 A
• 1 B
• 2 C
• 4 D