In a monumental breakthrough, scientists have recreated the universe’s first molecule, helium hydride (HeH⁺), solving a ...

Learn about the first ever molecule in the universe and its significance when it comes to the formation of the earliest stars ...

Helium hydride’s origin also marked the beginning of a chain reaction that led to the formation of molecular hydrogen (H2), which is by far the most common molecule in the universe, scientists say.

Note: The details of the chemical reactions that produce the different precipitates and different color changes are complicated. The main idea for students is that atoms or groups of atoms in the ...

Reversible: Physical changes can often be reversed by reversing the process that caused them (e.g., melting and freezing). No New Substance: No new substances are formed during a physical change.