Question

3. Given the formulas for two compounds:

H H H H
| | | |
H-C-C-O-C-C-H
| | | |
H H H H

And

H H H H
| | | |
H-C-C-C-C-H
| | | |
H H H H

These compounds differ in
(1) gram-formula mass
(2) molecular formula
(3) percent composition by mass
(4) physical properties at STP

Answer 1

The compounds differ in (2) molecular formula.

Step-by-step explanation

The molecular formula represents the actual number and types of atoms present in a molecule. In the given compounds, the arrangement of atoms is different, resulting in different molecular formulas.

The first compound is an organic molecule with a central oxygen atom (O) bonded to two carbon atoms (C) and two hydrogen atoms (H) on each side. Its molecular formula is C2H6O.

The second compound is an organic molecule with a chain of four carbon atoms (C) and 10 hydrogen atoms (H). Its molecular formula is C4H10.

Therefore, the compounds differ in their molecular formulas, as the arrangement and number of atoms are distinct. The other options mentioned, such as gram-formula mass, percent composition by mass, and physical properties at STP, may vary between compounds but are not the factors that differentiate these specific compounds in this context.