Balanced chemical equation:
* moles of oxygen
4 Al + 3 O2 = 2 Al2O3
4 moles Al -------------- 3 moles O2
9.30 moles Al ---------- moles O2
moles O2 = 9.30 * 3 / 4
moles O2 = 27.9 / 4 => 6.975 moles of O2
Therefore:
Molar mass O2 = 31.9988 g/mol
n = m / mm
6.975 = m / 31.9988
m = 6.975 * 31.9988
m = 223.19 of O2
The first animal was called the comb jelly
Answer: In creating a covalent bond, it would be best to bind oxygen to carbon (C ).
Covalent bonds result from electron-sharing between two atoms. One carbon atom combines with two oxygen atoms. Thus, the carbon dioxide molecule has two C=O bonds. Carbon dioxide is a very common covalent bond.
Answer: There are fossils found on either side of different continents and the continents look as though some are puzzle pieces that fit together.
Given the percentage composition of HC as C → 81.82 % and H → 18.18 %
So the ratio of number if atoms of C and H in its molecule can will be:
C : H = 81.82 12 : 18.18 1 C : H = 6.82 : 18.18 = 6.82 6.82 : 18.18 6.82 = 1 : 2.66 ≈ 3 : 8
So the Empirical Formula of hydrocarbon is:
C 3 H 8
As the mass of one litre of hydrocarbon is same as that of C O 2 The molar mass of the HC will be same as that of C O 2 i.e 44 g mol
Now let Molecular formula of the HC be ( C 3 H 8 ) n
Using molar mass of C and H the molar mass of the HC from its molecular formula is:
( 3 × 12 + 8 × 1 ) n = 44 n So 44 n = 44 ⇒ n = 1
Hence the molecular formula of HC is C 3 H 8
Does that help?
