Skip to main content
Ch.3 - Molecules, Compounds & Chemical Equations
Chapter 3, Problem 70

A salt crystal has a mass of 0.12 mg. How many NaCl formula units does it contain?

Verified Solution

Video duration:
2m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). For sodium chloride (NaCl), the molar mass is approximately 58.44 g/mol, calculated by adding the atomic masses of sodium (Na) and chlorine (Cl). Understanding molar mass is essential for converting between mass and the number of moles in chemical calculations.
Recommended video:
Guided course
02:11
Molar Mass Concept

Avogadro's Number

Avogadro's number, approximately 6.022 x 10²³, is the number of formula units, atoms, or molecules in one mole of a substance. This constant allows chemists to relate the macroscopic scale of substances (grams) to the microscopic scale (individual particles). It is crucial for determining how many formula units of NaCl are present in a given mass.
Recommended video:
Guided course
01:45
Avogadro's Law

Unit Conversion

Unit conversion is the process of converting a quantity expressed in one set of units to another. In this context, converting the mass of the NaCl crystal from milligrams to grams is necessary to use the molar mass effectively. This step is vital for accurately calculating the number of formula units present in the salt crystal.
Recommended video:
Guided course
01:56
Conversion Factors