The diameter of a hydrogen atom is 212 pm. Find the length in kilometers of a row of 6.02×10²³ hydrogen atoms. The diameter of a ping pong ball is 4.0 cm. Find the length in kilometers of a row of 6.02×10²³ ping pong balls.

Key Concepts

Avogadro's Number

Avogadro's number, approximately 6.02 x 10^23, is the number of atoms, ions, or molecules in one mole of a substance. This constant is fundamental in chemistry for converting between the number of particles and the amount of substance in moles, allowing for calculations involving large quantities of atoms or molecules.

Unit Conversion

Unit conversion is the process of converting a quantity expressed in one set of units to another set of units. In this problem, it involves converting diameters measured in picometers (pm) and centimeters (cm) to kilometers (km) to find the total length of a row of atoms or balls. Mastery of unit conversion is essential for solving problems in chemistry and physics.

Volume and Density Relationships

Understanding the relationship between volume, density, and dimensions is crucial in this context. The volume of an object can be calculated from its dimensions, and knowing the density allows for conversions between mass and volume. In this case, while not directly needed, recognizing how these concepts relate can help in visualizing the scale of the objects being compared.