Answer:
A) 
Explanation:
m = Mass of water = 38.9
M = Molar mass of water = 18 g/mol
= Avogadro's number = 
The reaction of electrolysis would be

Number of moles of 

From the reaction it can be seen that 2 moles of
gives 1 mole of 
So, number of moles of
produced is

Number of molecules

So,
of oxygen is produced.
Answer:
The nucleus, that dense central core of the atom, contains both protons and neutrons.
So to answer your question yes it does contain all of the protons in the atom.
* Hopefully this helps:) Mark me the brainliest:)!
Answer:
After the transfer the pressure inside the 20 L vessel is 0.6 atm.
Explanation:
Considering O2 as an ideal gas, it is at an initial state (1) with V1 = 3L and P1 = 4 atm. And a final state (2) with V2 = 20L. The temperature remain constant at all the process, thus here applies the Boyle-Mariotte law. This law establishes that at a constant temperature an ideal gas the relationship between pressure and volume remain constant at all time:

Therefore, for this problem the step by step explanation is:

Clearing P2 and replacing

Answer:
Atomic mass = mass of protons + mass of neutrons
Explanation:
In an element atomic mass of an atom can be calculated by adding the mass of protons and neutrons
I hope this helps! :)