how would you find molecular mass when given only density? (1.25g/L)
To find the molecular mass when given only the density (1.25 g/L), you need to know the identity of the substance. This is because different substances have different molar masses, even if they have the same density.
If you know the identity of the substance, you can use its density to determine its molar mass by following these steps:
1. Convert the given density to the appropriate units: In this case, the given density is 1.25 g/L, so no conversion is needed.
2. Use the molar mass formula: The molar mass (M) is equal to the density (d) multiplied by the molar volume (V). The molar volume is the volume occupied by one mole of a substance, and it depends on the temperature and pressure. At standard temperature and pressure (STP), the molar volume is approximately 22.4 L/mol.
3. Plug in the values: In this case, the density is 1.25 g/L and the molar volume at STP is 22.4 L/mol. Therefore, you can calculate the molecular mass using the formula:
M = d × V
= 1.25 g/L × 22.4 L/mol
4. Calculate the molecular mass: Multiply the density by the molar volume obtained from STP to find the molecular mass of the substance.
However, without knowing the identity of the substance, it is not possible to determine its molecular mass solely from the given density. The identity of the substance is crucial to determine the molar mass, as different substances can have the same density but different molecular masses.