Each of the following statements is true, but Dalton might...

Each of the following statements is true, but Dalton might have had trouble explaining some of them with his atomic theory. Give explanations for the following statements. a. The space-filling models for ethyl alcohol and dimethyl ether are shown below. These two compounds have the same composition by mass $(52 \%$ carbon, $13 \%$ hydrogen, and $35 \%$ oxygen), yet the two have different melting points, boiling points, and solubilities in water. b. Burning wood leaves an ash that is only a small fraction of the mass of the original wood. c. Atoms can be broken down into smaller particles.d. One sample of lithium hydride is $87.4 \%$ lithium by mass, while another sample of lithium hydride is $74.9 \%$ lithium by mass. However, the two samples have the same properties.

Each of the following statements is true, but Dalton might have had trouble explaining some of them with his atomic theory. Give explanations for the following statements.
a. The space-filling models for ethyl alcohol and dimethyl ether are shown below.
These two compounds have the same composition by mass $(52 \%$ carbon, $13 \%$ hydrogen, and $35 \%$ oxygen), yet the two have different melting points, boiling points, and solubilities in water.
b. Burning wood leaves an ash that is only a small fraction of the mass of the original wood.
c. Atoms can be broken down into smaller particles.d. One sample of lithium hydride is $87.4 \%$ lithium by mass, while another sample of lithium hydride is $74.9 \%$ lithium by mass. However, the two samples have the same properties.

Key Concepts

Isotopes

Isotopes are atoms of the same element that differ in neutron number and therefore have different atomic masses, even though their chemical properties remain nearly identical. This concept explains how compounds with the same chemical formula can sometimes show variations in percent composition by mass, a nuance that early atomic theories were unable to address.

Subatomic Structure

The understanding that atoms are not indivisible but are composed of smaller subatomic particles (protons, neutrons, and electrons) emerged after Dalton’s atomic theory. This concept explains why atoms can exhibit complex behavior and be broken down into additional layers of structure, which is critical for interpreting phenomena that early atomic models could not explain.

Chemical Reactions and Mass Distribution

In chemical reactions, especially combustion, the distribution of mass among products can change dramatically. Although the law of conservation of mass holds, the mass that remains in the residue (such as ash) is only a fraction of the original substance because many atoms are converted into gaseous products. This concept demonstrates that the observable mass after a reaction may not reflect the mass of the original material, due to the loss of volatile components.

Structural Isomerism

This concept refers to molecules that have the same molecular formula and, in some cases, even the same percent composition by mass, yet have different structures. These different structures lead to distinct physical and chemical properties, such as differences in melting points, boiling points, and solubilities. Structural isomerism highlights how the connectivity of atoms in a molecule can influence intermolecular interactions and overall behavior.