Some basic concepts of cheistry

Number of significant figures in

12.6 X 11.2

are:

• 6

• 3

• 4

• 2

A jug contains 2 L of milk. The volume of milk in m³ is:

• 0.02

• 2

• 0.002

• 0.0002

If 6.3 g of NaHCO₃ are added to 15.0 g of CH₃COOH solution, the residue is found to weigh 18.0 g. The mass of CO₂ released in the reaction is:

Hint: Law of conservation of mass.

• 7.2 g

• 3.3 g

• 20 g

• 27 g

Which of the following are true regarding Dalton's atomic theory? (Select all correct options)

• It failed to explain the nature of forces that bind together atoms in a molecule.

• It could not explain how and why atoms of different elements combine with each other to form compound atoms or molecules.

• It completely explained why atoms of different elements have different masses, sizes, valencies, etc.

• It explained the nature of forces that bind together atoms in a molecule.

Gram molecule of sugar in 547.2 gram are:

(Mol. mass of sugar = 342)

• 1.6

• 2.2

• 342

• 548

The number of moles of iodine in a sample containing 1.0 × 10²² molecules are:

• 6.022 X 10²³ Moles

• 0.0166 Moles

• 3 moles

• None of the above

The mass of 100 molecules of sucrose (C₁₂H₂₂O₁₁) is_________.

• 100 g

• 342 g

• 3.88 × 10^–20 g

• 5.68 × 10^–20 g

Number of atoms in 52 g of He are:

• 2.865 X 10²³

• 7.83 X 10²⁴

• 6.023 X 10²³

• 5000

The number of molecules present in 1 dm³ of Hydrogen at STP are:

• 2.69 X 10²²

• 2.19 X 10³⁵

• 6.023 X 10²³

• None of the above

The weight of carbon monoxide having same number of oxygen atoms as are present in 88 g of carbon dioxide are:

• 44 g

• 112 g

• 12 g

• 32 g