Law Of Constant Composition

The video tutorial explains chemical compounds, using water as an example to illustrate the law of constant composition. It details how to calculate the mass percentage of elements in compounds like water and hydrogen peroxide. The tutorial also covers how elements combine based on their positions in the periodic table and the bonds they form, using sodium chloride as an example. It concludes with a discussion on the law of constant composition, its limitations, and the concept of non-stoichiometric compounds like iron selenide.

What is the percentage mass of oxygen in a water molecule?

• 85%

• 92%

• 89%

• 78%

How do hydrogen and oxygen combine in hydrogen peroxide?

• One hydrogen and one oxygen atom

• Two hydrogen and one oxygen atom

• One hydrogen and two oxygen atoms

• Two hydrogen and two oxygen atoms

What determines the way elements combine to form compounds?

• Their color

• Their density

• Their position in the periodic table

• Their atomic number

What is the percentage mass of sodium in sodium chloride?

• 60%

• 50%

• 45%

• 39%

What is a characteristic of non-stoichiometric compounds?

• They are always superconductors

• They are always magnetic

• Their elemental composition varies between samples

• They have a fixed ratio of elements