Okay so because of the difference in density a simple method for telling the difference between the two is to put a sample in a container with oil, because water has a higher density than the oil it would sink to the bottom but alcohol on the other hand is lighter than oil and would float on top of the oil.
However with this question I think that what you would do is use the ice to find out what the substance is, it would float on top of the liquid if it were water because the water is denser than ice but the ice would sink if it was alcohol because the alcohol is less dense than ice.
I hope this helps you, good luck : )
Answer:
20 atoms
Explanation:
There are 4 in H2O2 because of 2 hydrogens and 2 oxygens.
Then, multiply by 5 because the coefficient is 5, therefore there are 5 H2O2 molecules.
5 x 4 = 20
