13.5g H2O = 13.5/(2+16) = 0.75 mol H2O
Since for every O2 you can form 2 H2O, 0.75/2 = 0.375 mol of O2 will be needed to form 0.75 mol of H2O.
Converting from moles to molecules:
0.375 mol * 6.022 * 10^23 = 2.26 * 10 ^23 molecules
Answer:
The answer is
<h2>0.307 g/cm³</h2>
Explanation:
The density of a substance can be found by using the formula

From the question
mass of box is 345 g
volume = 1125 cm³
The density of the object is

We have the final answer as
<h3>0.307 g/cm³</h3>
Hope this helps you