To determine the conditions that will allow you to obtain at least 27 g of water (H2O) from 5 g of hydrogen (H2) and 25 g of oxygen (O2), we need to consider the stoichiometry of the reaction. The balanced chemical equation for the formation of water from hydrogen and oxygen is:
2H2 + O2 -> 2H2O
According to the balanced equation, 2 moles of H2 react with 1 mole of O2 to produce 2 moles of H2O.
To calculate the number of moles of water formed, we divide the mass of water (27 g) by its molar mass (18.02 g/mol):
27 g / 18.02 g/mol = 1.496 mol ≈ 1.5 mol (rounded to the nearest tenth)
Therefore, by reacting 5 g of H2 and 25 g of O2, you will obtain approximately 1.5 moles of water. It's worth noting that the masses provided for H2 and O2 in your question are slightly different from the typical molar masses (2.02 g/mol for H2 and 32 g/mol for O2), which is why the calculated molar quantity is not exactly 1.5 moles.