1st Year Chemistry MCQS with Answers Chapter 1

Actual yield is mostly less than the theoretical yield due to the reason that

Rates of reactions are slow

Law of conservation of mass is not true

Loss of the product during handling

Reactions are never completed 100%

One mole of CH₃OH and one mole of C₂H₅OH have

Equal number of atoms

Equal number of protons

Equal number of molecules

Equal number of electrons

The separation of the different isotopes in the mass spectrometer is done on the basis of

Different m/e value

Different amounts of positive changes

Velocities of the ions

Charge e/m value different amounts of negative changes

The volume occupied by 1.6 g of O₂at STP is

1.12 dm³

112 dm³

2.24 dm³

22.4 dm³

In stoichiometric calculations

Side products can be formed

The reaction can be reversile

Law of definite proportions is definitely obeyed

Law of conservation of mass may not be obeyed

The volume occupied by 1.4 g on N₂at S.T.P is

2.24 dm³

112 cm³

1.12 dm³

22.4 dm³

The mass of one mole of electrons is

0.55 mg

0.184 mg

1.673 mg

1.008 mg