Explanation:
0 10 grams that that should be the answer
Mass of Oxygen required : 24 grams
<h3>Further explanation</h3>
Given
3 moles of H
1.5 moles of O
3 moles of H₂O
Required
Mass of O
Solution
Reaction
2H₂ + O₂ ⇒ 2H₂O
Mass of Oxygen for 1.5 moles of O :
= mol x Ar O
= 1.5 moles x 16 g/mol
= 24 grams
Answer: The sample that contains the greater number of molecules is water.
Explanation: To calculate the number of molecules, it is used the Avogadro's number ( 
particles/molecules). So, considering that the mass to water and carbon dioxide is 1g (it can be any other number), the relationship between moles and molar weight is:
To water: 
= 0.05 moles.
Therefore,
1 mol ---- molecules
0.05 moles ---- x
x = 
molecules of water.
To carbon dioxide: 
= 0.02 moles.
Therefore,
1 mol ---- molecules
0.02 moles ---- y
y = 
molecules of carbon dioxide.
