Answer:
9.35g
Explanation:
The molarity equation establishes that:

So, we have information about molarity (2M) and volume (80 ml=0.08 l), with that, we can find the moles of solute:


The mathematical equation that establishes the relationship between molar weight, mass and moles is:


We have MW (58.44g/mole) and n (0.16 mol), and we need to find m (grams of salt needed) to solve the problem:

Answer:
C
H²O is dissociated in water into H³O+ (hydronium ions) and OH- (hydroxide) given by;
2H²O <-----> H³O+ + OH-
If you notice initially we have 4 hydrogen atoms and 2 oxygen atoms. And similarly after the reaction we have 4 hydrogen atoms and 2 oxygen atoms.
Ratio of H to O is 4:2
or 2:1
This is very intuitive as we have 2 hydrogen atoms and 1 oxygen atom in a water molecule.