What is the mass, in grams, of 8.65 x 1025 atoms of oxygen?

Mass = 2304 g

Explanation:

Given data;

Number of atoms of oxygen = 8.65×10²⁵

Mass in gram = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.  The number 6.022 × 10²³ is called Avogadro number.

For example,

1 mole = 6.022 × 10²³ atoms

8.65×10²⁵ atoms of oxygen× 1mol  /6.022 × 10²³ atoms

1.44×10² mol

144 mol

Mass in grams of oxygen:

Mass = number of moles × molar mass

Mass = 144 mol × 16 g/mol

Mass = 2304 g

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally