Question

What is the mass of 4.5 x 10^22 molecules of hydrogen peroxide H2O2

2.54 g


3.2 g


1.78 g


4.61 g

Answer 1

The answer is 2.54g

To find the mass we must first find the number of moles we use the Formula ;

N = n × L

where

N is the number of entities

n is the number of moles

L is the Avogadro's constant which is

6.023 × 10^23

n = N / L

N = 4.5 x 10^22 molecules

n = 4.5 x 10^22 / 6.023 × 10^23

n = 0.0747 moles

Molar mass = mass / number of moles

Molar mass of H2O2 = (2 × 1) + (16 × 2)

= 2 + 32

= 34g/mol

mass = molar mass × number of moles

= 34 × 0.0747

= 2.5398

= 2.54g

Hope this helps