In a certain reaction 0.20g of hydrogen gas combines with 3.20g of oxygen gas.if the relative molecular mass of the compound is 34.0 find its molecular formula (H=1,O=16).
It's molecular mass is 2.The compound is H2O2.
In a certainreaction, 0.20g of hydrogen gas combines with 3.20g of oxygen gas.If the relative molecular mass of the compound is 34.0,find its molecular formula.(H=1,O=16
sounds like hydrogen peroxide
To find the molecular formula of the compound formed by the reaction of hydrogen and oxygen, we can follow these steps:
Step 1: Find the number of moles of each element in the reaction.
- Hydrogen gas (H2): Moles = mass / molar mass = 0.20g / 2g/mol = 0.10 mol
- Oxygen gas (O2): Moles = mass / molar mass = 3.20g / 32g/mol = 0.10 mol
Step 2: Determine the mole ratio between hydrogen and oxygen.
- From the balanced chemical equation for the reaction, we know that 2 moles of hydrogen combine with 1 mole of oxygen to form the compound.
Step 3: Compare the mole ratios.
- The mole ratio calculated in Step 2 matches the ratio of moles obtained in Step 1, suggesting that the compound formed is H2O.
Step 4: Calculate the molecular mass of the compound formed.
- Molecular mass of H2O = (2 x molar mass of H) + (1 x molar mass of O)
= (2 x 1g/mol) + (1 x 16g/mol)
= 18g/mol
Step 5: Find the ratio between the calculated molecular mass (18g/mol) and the given relative molecular mass (34.0).
- Ratio = relative molecular mass / calculated molecular mass
= 34.0 / 18
≈ 1.89
Step 6: Multiply the subscripts in the molecular formula by the ratio obtained in Step 5.
- Molecular formula = H2O
= (H2)1.89(O1)1.89
= H3.78O1.89
Therefore, the molecular formula for the compound formed by the reaction of hydrogen and oxygen is approximately H3.78O1.89.