Understanding Elements, Molecules, and Compounds

The video explains that elements have different personalities, with some being social and others preferring solitude. It introduces molecules as atoms linked by chemical bonds and distinguishes them from compounds, which are molecules made of different elements. Examples like O2 and CO2 illustrate these concepts. The video also covers diatomic elements and the characteristics of compounds, such as fixed ratios and distinct properties from their constituent elements. It concludes with methods to separate compounds, emphasizing chemical reactions like electrolysis.

Which of the following elements is known to be 'shy' and prefers to be alone?

• Hydrogen

• Oxygen

• Carbon

• Helium

What is formed when two oxygen atoms bond together?

• CO2

• H2O

• NaCl

• O2

Which statement is true about compounds?

• Compounds can be separated by physical means.

• Compounds are made of the same element.

• All compounds are molecules.

• All molecules are compounds.

What is the ratio of hydrogen to oxygen in a water molecule?

• 3:1

• 1:2

• 2:1

• 1:1

Which of the following is a compound?

• O2

• N2

• H2

• CO2

What is the fixed ratio of sodium to chlorine in table salt?

• 1:2

• 3:1

• 1:1

• 2:1

How can the elements in water be separated?

• By filtration

• By electrolysis

• By freezing

• By boiling

What happens to water when it is boiled?

• It turns into water vapor.

• It becomes a solid.

• It changes into a compound.

• It separates into hydrogen and oxygen.

Which process involves passing an electric current through water?

• Evaporation

• Filtration

• Electrolysis

• Distillation

What is a key characteristic of compounds?

• They are made of the same element.

• They have a fixed composition ratio.

• They can be separated by physical means.

• They are always gases.