A sample of water contains 5.24 x 1022 molecules. How many moles are in this sample?

0.087 moles of water

Explanation:

Given data:

Number of molecules of water = 5.24×10²² molecules

Number of moles of water = ?

Solution:

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.

1 mole = 6.022 × 10²³ molecules of water

5.24×10²² molecules × 1 mol / 6.022 × 10²³ molecules

0.87×10⁻¹ mol

0.087 mol

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3