<span>The balance format is
4NH3+ 5O2 -------> 4NO + 6H2O </span>
That is actually physics because it talks about motion.
Magnesium + Hydrocloric acid -> Magnesium chloride + hydrogen
You can observe a single displacement reaction
"Describe to show that the has formed is hydrogen"
I don't know what you mean. I can show the chemical equation though.
Mg(s) + 2 HCl(aq) --> MgCl 2(aq) + H 2(g)
The first option, collapsed in on itself.
The star's core mass becomes so dense that the resulting gravity implodes the star.
Interesting enough, the third option is kindof true too...some large and tenacious black holes that absorb other stars will form incredibly bright accretion disks around their perimeter before filling absorbing the star.