What is chemical reactions in a star?

Answer 1

There are many reactions going on in a star, all of them "nuclear fusion" reactions: making larger atoms out of smaller ones. The most common reaction is the formation of helium from 4 hydrogens. The special thing is that 4 hydrogens have more mass than a helium, and the extra mass is converted to energy, and so we can enjoy the warmth of the sun on a sunny day.

Specifically, there are 3 steps to convert 4 H's to a He:

1) H + H -> D (dueterium. hydrogen with 1 proton, 1 neutron)

2) D + H -> T (tritium. hydrogen with 1 proton, 2 neutrons)

3) T + H -> He (2 protons, 2 neutrons)

This same process can form all of the elements.