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.
Answer:
= 67.79 g
Explanation:
The equation for the reaction is;
4Cr(s)+3O2(g)→2Cr2O3(s)
The mass of O2 is 21.4 g, therefore, we find the number of moles of O2;
moles O2 = 21.4 g / 32 g/mol
=0.669 moles
Using mole ratio, we get the moles of Cr2O3;
moles Cr2O3 = 0.669 x 2/3
=0.446 moles
but molar mass of Cr2O3 is 151.99 g/mol
Hence,
The mass Cr2O3 = 0.446 mol x 151.99 g/mol
<u> = 67.79 g
</u>
Answer:
Explanation:
Relation between ΔG₀ and K ( equilibrium constant ) is as follows .
lnK = - ΔG₀ / RT
The value of R and T are same for all reactions .
So higher the value of negative ΔG₀ , higher will be the value of K .
Mg(s) + N₂0(g) → MgO(s) + N₂(g)
has the ΔG₀ value of -673 kJ which is highest negative value . So this reaction will have highest value of equilibrium constant K .
Answer:
Splitting water molecules produces hydrogen gas, which is used to power machines through hydrogen fuel cells. ( B-)
