Co(II) was used as an internal standard to analyze a sample of Ti(IV) with atomi

Question

Co(II) was used as an internal standard to analyze a sample of Ti(IV) with atomic absorption spectroscopy (AAS). A standard mixture containing 1.36 mu g Co/mL measured by AAS produced a signal-to-signal ratio of 1.94 Ti: 1.00 Co. A mixture was prepared by combining 4.00 mL of a Ti(IV) solution of unknown concentration with 3.50 mL of a 10.0 mu g/mL solution of Co(II). The absorbance of the mixture at the Ti(IV) wavelength was 0.169 and the absorbance at the Co(II) wavelength was 0.219. Determine the concentration, in moles per liter, of Ti(IV) in the original unknown solution. Number 2.35 times 10^-6 M Ti(IV)

Explanation / Answer

Absorbance propertional to concentration

ATi=KTiCTi=KTi*2.08

Aco=KCoCco=Kco*1.36

ATi/ACo = 1.94 given

KTi*2.08/Kco*1.36=1.94

KTi/Kco=1.2685

Now

CO(II)=10 µgml

Aco=0.219

ATi=0.169

So

0.169=KTi*CTi

0.219=KCo*10

0.169/0.219=KTi*CTi/KCo*10=(KTi/Kco)*(CTi/10)=1.2685*(CTi/10)

CTi=6.083 µg/ml (After mixing)

Original

Total volume =4+3.5=7.5 ml

Ti =4 ml

CTi =6.083*(7.5/4)=114.06 µg/ml = 114.06*10-6 gm/10-3 liter =0.114 gm/lit

Ti Motecular weight= 47.87 gm/mol

So CTi = 0.114 gm/lit/47.87 gm/mol=2.3828*10-3 M

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.