f a compound has an empirical formula of
C2HCl
what is the molecular formula if the molar mass is 179 g/mol?
Empirical formula mass = 2*12+1+35.5 = 60.5
179/60.5 = 2.96 which rounds to 3.0 as a whole number; therefore, the molar mass is (C2HCl)3 = ??
or it can be written as C6H3Cl3 = ??
Yes :)
Dtugguggh
To determine the molecular formula of a compound given its empirical formula and molar mass, we need to calculate the empirical formula mass and then compare it to the given molar mass. Here's how you can do it step by step:
Step 1: Calculate the empirical formula mass.
To calculate the empirical formula mass, we need to sum up the atomic masses of the elements in the empirical formula. The atomic masses of carbon (C), hydrogen (H), and chlorine (Cl) are approximately 12 g/mol, 1 g/mol, and 35.5 g/mol, respectively.
Empirical formula mass = (2 * atomic mass of C) + atomic mass of H + atomic mass of Cl
= (2 * 12 g/mol) + (1 * 1 g/mol) + (1 * 35.5 g/mol)
= 24 g/mol + 1 g/mol + 35.5 g/mol
= 60.5 g/mol
Step 2: Calculate the ratio of the molecular mass to the empirical formula mass.
The ratio of the molecular mass to the empirical formula mass can be calculated by dividing the given molar mass by the empirical formula mass.
Molar mass / Empirical formula mass = 179 g/mol / 60.5 g/mol
≈ 2.96
Step 3: Determine the subscripts of the molecular formula.
The ratio found in the previous step indicates the number of empirical formula units in the molecular formula. To convert this ratio to whole numbers, we need to round it to the nearest whole number.
Rounded ratio = 3
Now we can determine the subscripts in the molecular formula. Multiply each subscript in the empirical formula by the rounded ratio.
Molecular formula = (C2 * Rounded ratio) + (HCl * Rounded ratio)
= (C2 * 3) + (HCl * 3)
= C6H3Cl3
Therefore, the molecular formula of the compound with an empirical formula of C2HCl and a molar mass of 179 g/mol is C6H3Cl3.