Atoms and molecules

Which of the following statements is not true about an atom?

• Atoms are not able to exist independently

• Atoms are the basic units from which molecules and ions are formed

• Atoms are always neutral in nature

• Atoms aggregate in large numbers to form the matter that we can see, feel or touch

Which of the following has maximum number of atoms?

• 1g of H₂O

• 1g of O₂

• 1g of CO₂

• 1g of CH₄

• 40

• 30

• 50

• 68

• 32 times

• 12 times

• 8/3 times

• 12/32 times

The molecular formula of potassium nitrate is ________.

• KNO

• KON

• KNO₃

• KNO₂

Molecular mass is defined as the:

• Mass of one molecule of any substance compared with the mass of one atom of C – 12

• Mass of one atom compared with the mass of one atom of hydrogen

• Mass of one atom compared with the mass of one molecule

• none of these

To form a chemical formula, we need to know about

• the atomic mass of an element

• the mass of an element

• valency of an element

• all of these

H₂O can be classified in to which of the following category?

• Atom

• Molecule

• Compound

• Element

What does conservation of matter mean?

• Matter cycles through an ecosystem and 10% is lost as you move through each trophic level.

• Matter cannot be created, but can be destroyed.

• Matter cannot be created nor destroyed, and cycles through ecosystems.

• Matter and energy both move through ecosystems with 100% efficiency.

What is an element?

• A pure substance that cannot be broken down.

• Two atoms bonded together.

• Two or more different types of atoms bonded together.

• An molecule with an unequal distribution of charge.