The percentage of Chromium in Chromium Oxide is calculated as follow,
Step 1: Calculate Molar mass of Cr₂O₃,
Cr = 51.99 u
O = 16 u
So,
2(51.99) + 3(16) = 103.98 + 48 = 151.98 u
Step 2: Secondly divide molar mass of only chromium with total mass of Cr₂O₃ and multiply with 100.
i.e.
=

× 100
=
68.41 %
So, the %age composition of chromium in chromium oxide is
68.41 %.
Answer:
Kb = 

Explanation:
For a weak organic base, the formula to find
is given by:

where c is the concentration of base.
Here c= 

Substituting the above values in the formula,we get:

Hence:
Kb = 

Answer:
4.07L of a 0.110M NaF are needed
Explanation:
Based on the reaction:
SrCl₂(aq)+2NaF(aq)⟶SrF₂(s)+2NaCl(aq)
<em>1 mole of strontium chloride react with 2 moles of NaF</em>
<em />
361mL of 0.620M SrCl₂ solution has:
0.361L ₓ (0.620mol / L) = 0.22382 moles SrCl₂.
Moles of NaF for a complete reaction must be:
0.22382 moles SrCl₂ ₓ (2 mol NaF / 1 mol SrCl₂) = <em>0.44764 moles of NaF</em>
If you have a solution of 0.110M NaF, the moles of NaF needed are:
0.44764 moles of NaF ₓ (1L / 0.110mol NaF) = <em>4.07L of a 0.110M NaF are needed</em>
<em></em>