This preview shows pages 6–10. Sign up to view the full content.
Most elements in nature are mixtures ofMost elements in nature are mixtures of more than 1 isotope•“Average atomic mass” incorporates the“Average atomic mass” incorporates the relative abundance of each isotope in naturep+p+nnp+np+np+p+nnp+p+nnp+np+np+p+nnnp+p+nnp+np+np+p+nnnn6666 protons6 neutrons6 protons7 neutrons6 protons8 neutrons12C13C98.892 %1.108 %Trace amount (<0.001%)14C(stable)(stable)(radioactive)24S. Ensign, stoichiometry and calculations
has intentionally blurred sections.
Sign up to view the full version.
Average atomic mass of C found in naturep+p+nnp+np+nnp+p+nnp+np+nnnp+p+nnp+np+nnnnpnp+p+pnp+p+pnp+p+6 protons6 neutrons6 protons7 neutrons6 protons8 neutrons12C13C14C98.892 %12 amu1.108 %13.00335 amuTrace amount (<0.001%)25S. Ensign, stoichiometry and calculationsNaturally occurring bromine is composed of two isotopes which have atomic masses of 78.918336and 80.916289amu Isotope 1 is present at an abundance of 50 69%amu. 50.69%while isotope 2 is present at an abundance of 49.31%. Use this information to determine the average atomic f tll ibimass of naturally occurring bromine26S. Ensign, stoichiometry and calculationsThe atomic weights provided in a Periodic Table are the average atomic weights of the naturally occurring elements27S. Ensign, stoichiometry and calculationsFormula mass• Atoms have atomic masses (atomicAtoms have atomic masses (atomic weights)• Compounds have formula masses•Compounds have formula masses (formula weights)Tll tflth•To calculate formula mass, sum the atomic masses of all atoms in the llmolecule28S. Ensign, stoichiometry and calculations