Chapter 2, Problem 2.93E

Argon has three naturally occurring isotopes: 0.3336% 36Ar, 0.063% 38Ar, and 99.60% 40Ar. Estimate the average atomic mass of argon. If the masses of the isotopes are 35.968 u, 37.963 u, and 39.962 u, respectively, calculate the average atomic mass of natural argon.

2.72 How can an element have an atomic weight that is not an integer?

Early tables of atomic weights (masses) were generated by measuring the mass of a substance that reacts with 1.00 g of oxygen. Given the following data and taking the atomic mass of hydrogen as 1.00, generate a table of relative atomic masses for oxygen, sodium, and magnesium. Element Mass That Combines with 1.00Oxygen Assumed Formula Hydrogen 0.126g HO Sodium 2.875g Nao Magnesium 1.500g Mgo

The mass-to-charge ratio for the positive ion F+ is 1.97 107 kg/C. Using the value of 1.602 1019 C for the charge on the ion, calculate the mass of the fluorine atom. (The mass of the electron is negligible compared with that of the ion, so the ion mass is essentially the atomic weight.)

There are 2.619 1022 atoms in 1.000 g of sodium. Assume that sodium atoms are spheres of radius 1.86 and that they are lined up side by side. How many miles in length is the line of sodium atoms?

An alloy of iron (54.7%), nickel (45.0%), and manganese (0.3%) has a density of 8.17 g/cm3. How many iron atoms are there in a block of alloy measuring 10.0 cm 20.0 cm 15.0 cm?

The element silver (Ag) has two naturally occurring isotopes: 109 Ag and 107Ag with a mass of 106.905 u. Silver consists of 51.82% 107Ag and has an average atomic mass of 107.868 u. Calculate the mass of 109Ag.

The element europium exists in nature as two isotopes: 151Eu has a mass of 150.9196 u and 153Eu has a mass of 152.9209 u. The average atomic mass of europium is 151.96 u. Calculate the relative abundance of the two europium isotopes.

2.75 Chlorine has only two isotopes, one with mass 35 and the other with mass 37. One is present at roughly 75% abundance, and the atomic weight of chlorine on a periodic table is 35.45. Which must be the correct mass spectrum for chlorine?