An element X is composed of the isotopes X-14 and X-15 (see data table for mass and percent abundance of each isotope) isotope X-14 X-15 mass (amu) 14.003074 15.000109 percent abundance 99.6% 0.400 % Determine the average atomic mass of element X in amu. Answer to three decimal places.

An element has the following natural abundances and isotopic masses: 90.92% abundance with 19.99 amu, 0.26% abundance with 20.99 amu, and 8.82% abundance with 21.99 amu. Calculate the average atomic mass of this element.

The Mole Concept II Calculate the number of atoms in a pure gold ring weighing 17 g.

A gaseous binary compound has a vapor density that is 2.53 times that of nitrogen at 100°C and atmospheric pressure. When 8.21 g of the gas reacts with AlCl3 at 100°C, 1.62 g gaseous nitrogen is produced, removing all of the nitrogen originally present. (a) Estimate the molecular mass of the gaseous compound. (b) How many nitrogen atoms are there in a molecule of the compound? (c) What is the maximum possible value of the atomic mass of the second element? (d) Are other values possible for the atomic mass of the second element? Use a table of atomic masses to identify the element that best fits the data. (e) What is the molecular formula of the compound?