It is called exothermic reaction because it releases heat and light and it is called combustion reaction because it is reacting and is being oxidised by O2 to MgO.
It can also be called as oxidation reaction since Mg is oxidised to MgO.
Solid - made up of tightly packed particles, which gives it a solid shape.
Gas - made up of very loose particles, giving it more freedom to roam around as a gas
Liquid - fills into whatever it gets put in, basically takes the shape of the object its in
A sodium ion symbol is written as Na^+.
<span>acceleration I think.</span>
They are described through the use of four physical properties or macroscopic characteristics: pressure, volume, number of particles (chemists group them by moles) and temperature.