A sample of a substance that consists of carbon, fluorine, and hydrogen contains
ID: 534306 • Letter: A
Question
A sample of a substance that consists of carbon, fluorine, and hydrogen contains 8.38 grams of carbon, 13.3 grams of fluorine, and 1.41 grams of hydrogen. a. Calculate the empirical formula of the substance. b. If the molar mass of this substance is 66.05 g/mol, what is its molecular formula? A substance consisting of carbon, hydrogen and oxygen is converted into carbon dioxide (CO_2) and water (H_2 O) through combustion. A 0.5430 g sample of the compound produced 1.194 g of CO_2 and 0.3909 g of H_ 2 O. The molecular weight of the compound is 400, 4 g/mole. What are the compound's empirical and molecular formulas?Explanation / Answer
Ans 6
A) The mass of the sample = Sum of the masses of all its components.
= 8.38 + 13.3 +1.41 = 23.09 g
No. of moles of carbon in the sample = 8.38 / 12 = 0.7
hydrogen = 1.41/1 = 1.41
fluorine = 13.3 / 19 = 0.7
Divide all the number of moles by a common factor 0.7
We get the ratio of carbon : hydrogen : fluorine = 1: 2 : 1
So the empirical formula becomes : CH2F
B) The molar mass of the compound = 66.05 g/ mol
Empirical mass = 12 + 2 + 19 = 33 g
Molar mass / empirical mass = 66.05 / 33 = 2
Multiply the empirical formula by 2 to get the molecular formula
2 x (CH2F)
= C2H4F2