Suppose that a fictitious element, x, has two isotopes: 59x (59.015 amu) and 62x (62.011 amu). the lighter isotope has an abundance of 71.7%. calculate the atomic mass of the element x.

Achemist reacted 57.50 grams of sodium metal with an excess amount of chlorine gas. the chemical reaction that occurred is shown. na + cl2 → nacl if the percentage yield of the reaction is 86%, what is the actual yield? show your work, including the use of stoichiometric calculations and conversion factors.