Question

How many molecules are in 68.0 g of H2S

Answer 1

The correct answer is 12.044 × 10²³ molecules.  

The molecular mass of H₂S is 34 gram per mole.  

Number of moles is determined by using the formula,  

Number of moles = mass/molecular mass

Given mass is 68 grams, so no of moles will be,  

68/34 = 2 moles

1 mole comprises 6.022 × 10²³ molecules, therefore, 2 moles will comprise = 6.022 × 10²³ × 2

= 12.044 × 10²³ molecules.