Question

How many molecules are in 15.0 milliliters of ethanol (C2H3OH)(The density of ethanol is 0.789 g/mL)

Answer 1

1.57×10²³ molecules

Step-by-step explanation:

Given data:

Number of molecules of ethanol = ?

Volume of ethanol = 15.0 mL

Density of ethanol = 0.789 g/mL

Solution:

Mass of ethanol :

Density = mass/ volume

0.789 g/mL = mass/ 15.0 mL

Mass = 0.789 g/mL× 15.0 mL

Mass = 11.84 g

Number of moles of ethanol:

Number of moles = mass/molar mass

Number of moles = 11.84 g / 46.07 g/mol

Number of moles = 0.26 mol

1 mole contain 6.022×10²³ molecules

0.26 mol × 6.022×10²³ molecules / 1mol

1.57×10²³ molecules