ECAT Pre Engineering Chemistry Chapter 1 MCQ Test With Answer

He Ar and Ne are:

• Mono-atomic molecules A

• Hetero atomic molecules

  B

• Poly-atomic molecules

  C

• Diatomic molecules

  D

A limiting reactant is the one which

• Is taken in lesser quantity in grams as compared to other reactants A
• Is taken in lesser quantity in volume as compared to other reactants B
• Gives the maximum amount of the product which is required C
• Gives the minimum amount of the product under consideration 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

Mass spectrometer measures the

• Exact mass of an element A
• Average mass of an element B
• The number of elements present in a molecule C
• m/e value of a positive ion D

NH₃, HCL, H₂O, HL are:

• Diatomic molecules

  A

• Poly-atomic molecules

  B

• Mono-atomic molecules

  C

• Hetero atomic molecules

  D

The percentage of which element in the organic compound is determined by the difference method

• Carbon A
• Hydrogen B
• Nitrogen C
• Oxygen D

One of the following statements is incorrect

• Actual yeild is always less than the theoretical yield A
• The formula of a compound is not definite B
• Law of conservation of mass is applied in stoictiometry C
• Boyles law is applied in stoichiometry D

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

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

Which has greater number of moles

• 0.1 g sodium A
• 6.02 x 10²⁰atoms of magnesium B
• 20 cm³0.1mole per dm³of NaOH C
• 12.2 dm³of nitrogen at standard
  [A_rNa = 23, Mg = 24, O = 16]
  D

The number of isotopes of gold is

• 3 A
• 1 B
• 2 C
• 4 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

Which of the sub-atomic particles is not charged

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

The amount of products obtained from the balanced chemical equation is regarded as

• Theoretical yield A
• Actual yield B
• % yield C
• Experimental yield 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 compound having empirical formula C₃H₃O and its molecular mass is 110.02. Its molecular formula is

• C₃H₃O A
• C₆H₆O₂ B
• C₉H₉O₃ C
• C₃H₆O₂ 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

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

• N₂O₄is limiting reactant A
• N₂H₄is the limiting reactant B
• Reactants are completely converted to the products C
• Reactions is reversible D

• 
  A
• 
  B
• 
  C
• 
  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

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

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

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

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

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

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

• C A
• H B
• N C
• O D

A molecule of haemoglobin is made up if nearly

• 10,000 atoms A
• 50,000 atoms B
• 2500 atoms C
• 1500 atoms D

Hemoglobin is 68000 times heavier than:

• Oxygen atom A
• Nitrogen atom B
• Carbon atom C
• Hydrogen atom 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

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