Determine the number of moles (of molecules or formula units) in each sample. b. 23.6 kg Fe(NO₃)₂

Verified step by step guidance

1. Convert the mass of the sample from kilograms to grams. Since 1 kg = 1000 g, multiply 23.6 kg by 1000 to get the mass in grams.
2. Calculate the molar mass of Fe(NO_3)_2. To do this, add the atomic masses of all the atoms in the formula: Fe, N, and O. Use the periodic table to find these atomic masses.
3. The molar mass of Fe(NO_3)_2 is the sum of the atomic masses: 1 Fe, 2 N, and 6 O. Calculate this value.
4. Use the formula: number of moles = mass (g) / molar mass (g/mol). Substitute the mass in grams and the molar mass you calculated into this formula.
5. Solve the equation to find the number of moles of Fe(NO_3)_2 in the sample.

Key Concepts

Moles and Avogadro's Number

A mole is a unit in chemistry that represents 6.022 x 10^23 entities, such as atoms or molecules. This concept is fundamental for converting between the mass of a substance and the number of moles, allowing chemists to quantify and compare amounts of different substances.

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all atoms in a molecule. For Fe(NO3)2, the molar mass is essential for converting the given mass (23.6 kg) into moles.

Unit Conversion

Unit conversion is the process of converting a quantity expressed in one set of units to another. In this context, it involves converting kilograms to grams (1 kg = 1000 g) to facilitate the calculation of moles from mass using the molar mass of Fe(NO3)2.