Please help with chemistry problem?

Question

Adipic acid is used in the manufacture of nylon. The composition of the acid is 49.3% C, 6.9% H, 43.8% O (by mass) and the molecular weight is 146 amu. What is the molecular formula?

Please please help me with this. Thanks in advance!

Answer 1

We consider 100 g
Moles C = 49.3 g / 12.011 = 4.10
Moles H = 6.9g / 1.0079 = 6.85
Moles O = 43.8 g/ 15.9994 = 2.74
We divide by the smallest number
C (1.5) H (2.5) O
To obtain whole numbers we multiply by 2
C3H5O2 ( empirical formula) => mass = 73
146 / 73 = 2
The molecular formula is
C6H10O4

Answer 2

49.3%/12 = 4.11

6.9%/1 = 6.9

43.8%/16 = 2.74

4.11/2.74 = 1.5

6.9/2.74 = 2.52

2.74/2.74 = 1.0

So the formula with best whole numbers is C3H5O2. That is the empirical formula, with a formula weight of 73. The molecular weight is 146, which is twice that, so the molecular formula is C6H10O4.

Answer 3

assume you have 100 g of the compound
find # of moles of each element
49.3 g C x (1 mol C / 12.01g) = 4.10 mol C
6.9 g H x (1 mol H / 1.008 g) = 6.85 mol H
43.8 g O x (1 mol O / 16.00 g) = 2.74 mol O

now find the simplest whole number ratio between them - divide each by the smallest, 2.74
4.10 C / 2.74 = 1.5
6.85 H / 2.74 = 2.5
2.74 O / 2.74 = 1

mult each by 2 to get whole numbers
C - 3
H - 5
O - 2
the empirical formula is C3H5O2
find the molar mass of that compound: 73.07 g/mol

146 / 73.07 = 2 - so multiply the empirical formula by 2 to get the molecular formula

C6H10O4

Answer 4

Because evaporation of a liqiud needs heat energy to change to gaseuos phase. So the liqiud takes heat energy from the surrounding causing cooling Example: when u come out of the swimming pool, u feel cold because the water on ur body absorbs heat energy from ur body to evaporate .