A sample of the male sex hormone testosterone, C₁₉H₂₈O₂, contains 3.88×10²¹ hydrogen atoms. (b) How many molecules of testosterone does it contain?

Verified step by step guidance

1. Identify the number of hydrogen atoms in one molecule of testosterone, which is given by the chemical formula \( \text{C}_{19}\text{H}_{28}\text{O}_{2} \). This indicates there are 28 hydrogen atoms per molecule.
2. Use the given number of hydrogen atoms, \( 3.88 \times 10^{21} \), and divide it by the number of hydrogen atoms per molecule (28) to find the number of testosterone molecules.
3. Set up the division: \( \frac{3.88 \times 10^{21}}{28} \).
4. Perform the division to calculate the number of testosterone molecules.
5. The result from the division will give you the number of testosterone molecules in the sample.

Key Concepts

Avogadro's Number

Avogadro's number, approximately 6.022 x 10^23, is the number of atoms, ions, or molecules in one mole of a substance. This constant is crucial for converting between the number of particles and the amount of substance in moles, allowing chemists to relate macroscopic quantities to microscopic entities.

Molecular Formula

The molecular formula of a compound indicates the number and type of atoms present in a molecule. For testosterone, C19H28O2 signifies that each molecule contains 19 carbon atoms, 28 hydrogen atoms, and 2 oxygen atoms. Understanding the molecular formula is essential for determining the number of molecules from the total number of atoms.

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. In this context, it helps in calculating the number of molecules of testosterone based on the total number of hydrogen atoms, using the ratio of hydrogen atoms per molecule as defined by its molecular formula.