How many molecules (or formula units) are in each sample? a. 85.26 g CCl₄ b. 55.93 kg NaHCO₃ c. 119.78 g C₄H₁₀ d. 4.59×10⁵ g Na₃PO₄

Verified step by step guidance

1. insert step 1: Identify the molar mass of each compound. For example, calculate the molar mass of CCl4 by adding the atomic masses of one carbon atom and four chlorine atoms.
2. insert step 2: Convert the given mass of each sample to moles using the formula: moles = mass (g) / molar mass (g/mol).
3. insert step 3: Use Avogadro's number (6.022 x 10^23) to convert moles to molecules or formula units. The formula is: number of molecules = moles x Avogadro's number.
4. insert step 4: Repeat the process for each compound: CCl4, NaHCO3, C4H10, and Na3PO4.
5. insert step 5: Ensure all units are consistent, especially when converting kg to g for NaHCO3, and verify calculations for accuracy.

Key Concepts

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. Understanding molar mass is essential for converting between grams and moles, which is necessary for determining the number of molecules in a given mass of a substance.

Avogadro's Number

Avogadro's number, approximately 6.022 x 10^23, is the number of particles (atoms, molecules, or formula units) in one mole of a substance. This constant allows chemists to relate the macroscopic scale of substances (grams) to the microscopic scale (number of molecules), making it crucial for calculations involving the number of molecules in a sample.

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It involves using balanced chemical equations to calculate the amounts of substances involved. In the context of the question, stoichiometry helps in determining how many molecules correspond to a given mass of a compound by applying molar mass and Avogadro's number.