Question 1 of 10 eos
How does one determine an empirical formula from a percent composition?
7x
A. Convert mass percents to moles and then use the moles as
subscripts in the formula
B. Convert mass percents to moles and then divide by the smallest
mole value to get subscripts
C. Convert mass percents to grams and then divide by the smallest
gram value to find subscripts
o)
D. Convert mass percents to grams and then divide by the smallest
mass percent value to find subscripts
kamp
SUBMIT

B. Convert mass percents to moles and then divide by the smallest mole value to get subscripts

Explanation:

The empirical formula is the smallest whole number ratio the elements in a compound can possess. According to this question, to derive the empirical formula of a compound from its percent composition of elements that make it up, the following steps are followed:

- First, since the elements are in percentage, one would assume the total mass of the compound is 100g and take each percentage as the mass of each element. For example, if a compound contains 16% oxygen, it means that 16g of oxygen is present.

- Next, we convert the mass of each element to moles by dividing the mass value by the molar mass of each element. For example, 16g of oxygen will be 16g/16g/mol = 1mol

- Next, we divide each mole value by the smallest mole value to get the subscript of each element that will be used in the empirical formula.

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.