Answer:
a. Oxygen
b. 20.39g of Al₂O₃
c. 87%
Explanation:
In order to produce 2moles of Al₂O₃, we need to make react 4 moles of Al, to 3 moles of O₂.
We determine the limiting reactant with the moles of each:
12.98g / 26.98g/mol = 0.481 moles of Al
9.6g / 32g/mol = 0.300 moles of oxygen
4 moles of Al react to 3 moles of O₂
Then, 0.481 mol may react to (0.481 . 3)/4 = 0.361 moles
We only have 0.300 moles of O₂ and we need 0.361. Oxygen is the limiting reactant.
So 3 moles of O₂ can produce 2 moles of Al₂O₃
Our 0.300 moles may produce (0.300 . 2) / 3 = 0.200 mol
Our theoretical yield is: 0.2 mol . 101.96g/ mol = 20.39 g
To determine the percent yield we calculate:
(Produced yield/ Thoeretical yield) . 100 → (17.74 /20.39) . 100 = 87%
He thought elements that haven't been discovered belonged in the place of the gap. He could also use the atomic mass of the missing elements
-Plant cells have cell walls to keep the cell rigid, but animal cells don't
-Plant cells have a large permanent vacuole, but animal cells don't. Animal cells will either have a small vacuole or none at all.
-Plant cells have chloroplasts, which contain chlorophyll, so photosynthesis can take place. Animal cells don't need to photosynthesise and therefore do not need chloroplasts.
-Animal cells contain flagella, but in plant cells flagella is only found in gametes(sex cells)
[Ar] 3s^23p^6 since Ar is in period 3 and have all the orbitals filled with electrons