Question

how many grams of oxygen are there in 2.5 moles of oxygen (o₂) molecules? select the correct answer below: 16 g 40. g 80. g 120 g

Explanation:

Step1: Determine molar - mass of O₂

The molar mass of O is 16 g/mol. For O₂, molar mass $M = 2\times16\ g/mol=32\ g/mol$.

Step2: Use the mole - mass formula

The formula is $m = n\times M$, where $n = 2.5\ mol$ (number of moles) and $M = 32\ g/mol$ (molar mass). Then $m=2.5\ mol\times32\ g/mol = 80\ g$.

Answer:

C. 80. g