Question

50 CH.CH 2.44 0.0643 51 A mothball, composed of naphthalene (CH), has a mass of 1.32 g How many naphthalene molecules does it contain?

Answer 1

Ans :

Moles of naphthalene = mass / molar mass

molar mass = 128.1705 g/mol

so number of moles :

mol = 1.32 g / 128.1705 g/mol

= 0.0103 mol

Each mol compound has 6.022 x 10²³ molecules

so here number of molecules of naphthalene will be : mol x 6.022 x 10²³

= 0.0103 mol x 6.022 x 10²³ molecules/mol

= 6.20 x 10²¹ molecules