Answer:
Explanation:
Molar ratio for Sg : FeS = 1:8
If there are 0.3 moles for Sg
Therefore, 0.3 × 8 =2.4 moles of FeS
Mass = Moles/ Mr
Mr of FeS = 56+32=88
So mass = 2.4/88
Mass= 0.027g
It took 380,000 years for electrons to be trapped in orbits around nuclei, forming the first atoms.
These were mainly helium and hydrogen, which are still by far the most abundant elements in the universe. Present observations suggest that the first stars formed from clouds of gas around 150–200 million years after the Big Bang. Heavier atoms such as carbon, oxygen and iron, have since been continuously produced in the hearts of stars and catapulted throughout the universe in spectacular stellar explosions called supernovae.
A) Burning
Burning is a chemical reaction while the other three answers are physical reactions.
Answer:
23
Explanation:
we do not care about electrons, so 11 + 12 = 23
