Answer:
let's do no.3
Na2O+H2SO4 > Na2SO4 +H2O
Al2O3+3H2SO4>Al2(SO4)3+3H2O
the three before the sulphuric acid is such that the equation balances on both ends
...hope this helps
Given :
10 gram sample of propane( C₂H₈ ).
To Find :
The number of moles of propane in given sample.
Solution :
Molecular mass of propane, M = (2 × 12) + ( 1 × 8 ) gram/mol
M = 32 gram/mol
We know, number of moles is given by :
Number of moles, n = m/M
n = 10/32 mol
n = 0.3125 mol
Therefore, number of moles in given sample is 0.3125 mol.