The molar mass of carbon-13 (^{13}C) is approximately 13.00335 grams per mole.
Carbon exists in several isotopes, with carbon-12 (^{12}C) being the most abundant isotope, while carbon-13 is a stable isotope that makes up about 1.1% of natural carbon. To understand the molar mass, we look at the mass number of an isotope, which is the total number of protons and neutrons in the nucleus. For carbon-13, there are 6 protons and 7 neutrons, resulting in a mass number of 13. When we calculate molar mass, we use the atomic mass unit (amu) scale, where 1 amu is defined as one twelfth the mass of a carbon-12 atom. Carbon-13’s molar mass reflects this consideration, with its precise measurement accounting for slight variations in weight due to its unique neutron count. Therefore, when conducting experiments or calculations involving carbon-13, using its molar mass of 13.00335 g/mol is essential for accurate results.