Question

approximately how many atoms are in 12.6 grams of oxygen (o)? 2.37 x 10^12 1.95 x 10^32 4.74 x 10^23 d. 5.89 x 10^25

Explanation:

Step1: Determine molar - mass of oxygen

The molar - mass of oxygen (O) is approximately 16 g/mol.

Step2: Calculate the number of moles

Use the formula $n=\frac{m}{M}$, where $m = 12.6$ g and $M = 16$ g/mol. So, $n=\frac{12.6}{16}=0.7875$ mol.

Step3: Use Avogadro's number

Avogadro's number $N_A = 6.022\times10^{23}$ atoms/mol. The number of atoms $N=n\times N_A$.
$N = 0.7875\times6.022\times10^{23}$
$N=(0.7875\times6.022)\times10^{23}$
$0.7875\times6.022 = 4.74375\approx4.74$
So, $N = 4.74\times10^{23}$ atoms.

Answer:

B. $4.74\times10^{23}$