If 9.03 x 1021 molecules of a compound having general formula CnH2n+2 weigh 1.71g, what is the molar mass of the compound? Give its molecular formula
To find the molar mass of the compound, you need to know the number of moles of the compound and the mass of those moles. Since you have the number of molecules and their mass, you can calculate the molar mass with the following steps:
Step 1: Find the number of moles using Avogadro's number.
- Avogadro's number is 6.022 x 10^23, which represents the number of particles (molecules or atoms) in one mole.
- Divide the number of molecules you have by Avogadro's number to get the number of moles.
9.03 x 10^21 molecules / (6.022 x 10^23 molecules/mol) = 0.01498 moles
Step 2: Calculate the molar mass by dividing the mass of the compound by the number of moles.
- Divide the mass of the compound (1.71 g) by the number of moles (0.01498 moles) using the formula:
Molar mass = Mass of the compound / Number of moles
Molar mass = 1.71 g / 0.01498 moles = 114.09 g/mol
Therefore, the molar mass of the compound is 114.09 g/mol.
To determine the molecular formula of the compound, you need to know the number of carbon and hydrogen atoms present. From the general formula CnH2n+2, you can determine the ratio of carbon to hydrogen.
In this case, the ratio is 1 carbon atom to 2 hydrogen atoms. Now we need to find the value of n for this compound.
Step 3: Calculate the value of n.
From the molecular formula, we can see that for every 1 mole of CnH2n+2, there are n moles of carbon atoms and 2n+2 moles of hydrogen atoms.
Since we know that we have 0.01498 moles of the compound, we can extract the value of n by comparing moles of carbon to moles of the compound.
Moles of carbon = 0.01498 moles
Moles of compounds = n moles
Therefore, n = 0.01498 moles
Step 4: Determine the whole number value of n.
To find the whole number value of n, you can multiply the fractional value by a whole number to get a whole number ratio.
In this case, multiply n by 66 (a number that gives a ratio as close to 1 as possible).
Whole number n = 0.01498 moles x 66 ≈ 1
Hence, the molecular formula of the compound is C1H4, which can be simplified to CH4, representing methane.