Answer:
Molar mass = 151.9 g/mol
Explanation:
The molar mass of a compound is obtained by adding u the individual atomic masses in the compound. The unit is g/mol.
In FeSO4, we have one Fe, one S and 4 O.
The atomic masses are given as follows;
Fe = 55.845 u
S = 32.065 u
O = 15.999 u
Molar mass = ( 1 * Fe) + (1 * S) + (4 * O)
Molar mass = (1 * 55.854 ) + ( 1 * 32.065) + (4 * 15.999)
Molar mass = 151.915 g/mol
In four significant figures;
Molar mass = 151.9 g/mol
First, we need the no.of moles of O2 = mass/molar mass of O2
= 55 g / 32 g/mol
= 1.72 mol
from the balanced equation of the reaction:
2H2 (g) + O2(g) → 2H2O(g)
we can see that the molar ratio between O2: H2O = 1: 2
So we can get the no.of moles of H2O = 2 * moles of O2
= 2 * 1.72 mol
= 3.44 mol
So by substitution by this value in ideal gas formula:
PV = nRT
when P = 12.4 atm & n H2O = 3.44 mol & R= 0.0821 & T = 85 + 273=358K
12.4 atm *V = 3.44 * 0.0821 * 358 = 8.15 L
∴ V ≈ 8.2 L
228 grams
start with mass of Cr multiply by molar mass of Cr mole to mole ratio between Cr and Cr2O3 times molar mass of Cr2O3