an unknown molecule is found to consist of 24.2% carbon by mass, 4.0% hydrogen by mass and the remaining mass is due to chlorine

Question

djverab [1.8K]

3 years ago

6

an unknown molecule is found to consist of 24.2% carbon by mass, 4.0% hydrogen by mass and the remaining mass is due to chlorine

. what is the molecular formula of the molecule given that the molar mass is found to be approximately 150?

Chemistry

2 answers:

solniwko [45] · Answer 1 · 2021-12-12T06:33:05+03:00

Answer: C3 H6 Cl3

Explanation:

Molecular formula = (Empirical formula)n

where n= num of moles

Then, let's calculate empirical formula

The molecule consists of Carbon (24.2%), Hydrogen (4.0%) and Chlorine (??)

The abundance of Chlorine is = 100% - ( 24.2% + 4.0%)

= 100% - 28.4%

= 71.8%

Therefore, we have, Carbon 24.2%, Hydrogen 4.0% and Chlorine 71.8%

C H Cl

24.2 4.0 71.8

divide each by mass its num 12 1 35.5

2 4 2

Divide through by the smallest 2 2 2

(i.e. 2) 1 2 1

Therefore, the empirical formula= CH2Cl

Molecular formular = (CH2Cl)n

But n = ??

(CH2Cl)n = 150; C=12, H=1, Cl=35.5

(12 + (2 x 1) + 35.5 )n = 150

(49.5)n = 150

n=3

Therefore, Molecular fromula = (CH2Cl)3

= C3 H6 Cl3

Paha777 [63] · Answer 2 · 2021-12-12T05:31:22+03:00

Answer:

C3 H6 Cl 3

Explanation:

C -24.2%

H - 4.0%

Cl - (100-24.2 - 4.0)=73.8 %

We can take 100g of the substance, then we have

C -24.2 g

H - 4.0 g

Cl - 73.8 g

Find the moles of these elements

C -24.2 g/12.0 g/mol =2.0 mol

H - 4.0 g/1.0 g/mol = 4. 0 mol

Cl - 73.8 g/ 35.5 g/mol = 2.1 mol

Ratio of these elements gives simplest formula of the substance

C : H : Cl = 2 : 4 : 2 = 1 : 2 : 1

CH2Cl

Molar mass (CH2Cl) = 1*12.0 +2*1.0 + 1*35.5 = 49.5 g/mol

Real molar mass = 150 g/mol

real molar mass/ Molar mass (CH2Cl) = 150 /49.5=3

So, Real formula should be C3 H6 Cl 3.