Let's start with the amount given in percent. Let our basis be 100 grams of compound. So, that means that in this amount, 57.1 g is oxygen and 100-57.1=42.9 g is carbon. Since there is 1:1 atom ratio, it also means that moles oxygen = moles carbon.
Moles = Mass/Relative Mass
Let x be the relative mass of oxygen
57.1/16 = 42.9/x
Solving for x,
<em>x = 12.02 amu</em>
Answer:
Benzene
Explanation:
You need to calculate the densities for each compound.
EtOH = 5.85/7.5 = 0.78 g/mL
Benzene = 6.60/7.5 = 0.88 g/mL
0.88 > 0.78, thus benzene is denser than ethanol.