The reaction of excess oxygen with an unknown volume of hydrogen at 200 c yields 3.22 l of steam. what is the volume of the hydrogen -pressure

its first and third is your answer i did the qustion the fourth isnt right

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.