Step 1
The reaction must be written, completed, ad balanced:
2H2 + O2 = 2H2O
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Step 2
Avogadro's Number will be used here and it states that:
1 mole of substance = mass of the substance = 6.02x10^23 formula units (molculesin theis case)
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Step 3
Information needed:
Mass per mole of H2 = 2.01 g
Information provided:
5.35x10^25 molecules of O2
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Step 4
Procedure:
2 x 2.01 g H2 ------- 6.02x10^23 molecules O2
X ------- 5.35x10^25 molecules O2
X = 5.35x10^25 molecules O2 x 2 x 2.01 g H2/6.02x10^23 molecules O2
X = 357.3 g H2
Answer: 357.3 g H2