Molarity refers to moles/ L. This indicates the concentration of a solution containing solute and solvent.
1 molar solution contains 1 mole of solute in 1 L of solvent.
According to Avogadro's number, 1 mole of a substance contains 6.023 x 10^23 molecules, atoms, or ions.
For this reason, 6.023 x 10^23 atoms, ions, or molecules are in a molar solution.
The new volume : 0.07 L
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Further explanation</h3>
Boyle's Law
At a constant temperature, the gas volume is inversely proportional to the pressure applied

P₁=1 atm
V₁=0.39 L
P₂=5.6 atm

The answer from this questions is the letter
B. He should not use his opinions as evidence.
Valence.
The electrons in the outer shell of an atom are called valence electrons.
Valence electrons determine whether the an element is ready form compounds. These electrons can be gained, lost, or shared in the formation of compounds.
Hydrogen is the limiting reactant because when doing a stoichiometry equation for the reactants, hydrogen will be used completely by having a smaller yield and oxygen will be excess (7 moles to be exact)