I wish I could help but I’m not sure sorry
Answer: Fireworks exploding is a chemical change.
Explanation: Lighting gunpowder, and making the explosion is a chemical change.
The energy of an electron in a hydrogen atom is:
<span>E= (-2.179 x 10 ^-18 J)(1/n^2)
</span>where n is the principle energy level of the electron.
<span>
E= (-2.179 x 10 ^-18 J)(1/4)
</span><span>E= -2.179 x 10 ^-18 J
</span>E = -5.4 <span>x 10 ^-19 J</span>
Explanation:
Things that float=paper,plastic bottle,rubber, polythene bag, balloon
Things that sinks =needle,stone,spoon,pen,soap
The age of the fossil n how they look??