Unknown 2 Scheme Lab Report
Unknown 2 Scheme
“ Fair game” ions
Cations: Na+, K+, NH4+ , Ca2+, Mg(OH2)62+ , Al(OH2)63+
Anions: SO42-, HSO4-, NO3-, OH-, Cl-, CO32-, HCO3-
Insoluble Compounds: Ca(OH)2, CaSO4•2H2O, CaCO3, MgCO3, Mg(OH)2
I. Describe Sample
a. Quick description of sample. Ex: Phase, color, odor, crystalline, amorphous, gel-like, powdery, etc.
II. Flame Test
a. Part 1
i. Orange Flame: Na+ is present. K+ , NH4+ , Ca2+, Mg(OH2)62 , Al(OH2)63+ may also be present. ii. Purple Flame: K+ is present (no Na+ or Ca2+ ). NH4+ could also be present. iii. Red Flame: Ca2+ is present. (no Na+) All other possible. iv. No color means NH4+, Mg(OH2)62+ ,or Al(OH2)63+ is present. ( no Na+ , K+ , or Ca2+)
b. Part 2
i. Dissolve a small same of the solid unknown …show more content…
Anions Test
a. Cl- Test
i. Add excess of 6 M HNO3 drops to a sample of your unknown until solution turns acidic. Use blue litmus paper to see when it turns red. Then add excess of .02 M AgNO3. ii. If a white precipitate forms then we know Cl- is present.
b. SO42- / HOSO3- Test
i. Add excess 6 M HNO3 drops to a sample of your unknown until solution turns acidic. Use blue litmus paper to see when it turns red. Then add one drop of .25 M Ba (NO3)2. ii. If a white precipitate forms we know that either SO42- or HOSO3- is present. If HSO4- is present then SO42- is present. iii. To determine which is present we need to find the pH using indicators. If is has a pH of 2 HSO4 is present. If it has a pH of 4 then SO4 is present. iv. Indicators used: Bromythl Blue, Methyl Orange, and Methyl Violet.
c. NO3- Test
i. Place a few single small crystal of Fe(OH2)6(H4N)2(SO4)2 in a shallow watch glass. Cover the crystals with the unknown solution. Then immediately add excess drops of 18 M H2SO4 . ii. If a brown precipitate forms then NO3- is present.
VIII. Insoluble Test
a. Treat with 1M HCl
i. If it dissolves perform flame test
1. Red / Red Orange flame: Ca(OH)2
2. No color: Mg(OH)2 ii. If it dissolves with bubbles perform flame
“ Fair game” ions
Cations: Na+, K+, NH4+ , Ca2+, Mg(OH2)62+ , Al(OH2)63+
Anions: SO42-, HSO4-, NO3-, OH-, Cl-, CO32-, HCO3-
Insoluble Compounds: Ca(OH)2, CaSO4•2H2O, CaCO3, MgCO3, Mg(OH)2
I. Describe Sample
a. Quick description of sample. Ex: Phase, color, odor, crystalline, amorphous, gel-like, powdery, etc.
II. Flame Test
a. Part 1
i. Orange Flame: Na+ is present. K+ , NH4+ , Ca2+, Mg(OH2)62 , Al(OH2)63+ may also be present. ii. Purple Flame: K+ is present (no Na+ or Ca2+ ). NH4+ could also be present. iii. Red Flame: Ca2+ is present. (no Na+) All other possible. iv. No color means NH4+, Mg(OH2)62+ ,or Al(OH2)63+ is present. ( no Na+ , K+ , or Ca2+)
b. Part 2
i. Dissolve a small same of the solid unknown …show more content…
Anions Test
a. Cl- Test
i. Add excess of 6 M HNO3 drops to a sample of your unknown until solution turns acidic. Use blue litmus paper to see when it turns red. Then add excess of .02 M AgNO3. ii. If a white precipitate forms then we know Cl- is present.
b. SO42- / HOSO3- Test
i. Add excess 6 M HNO3 drops to a sample of your unknown until solution turns acidic. Use blue litmus paper to see when it turns red. Then add one drop of .25 M Ba (NO3)2. ii. If a white precipitate forms we know that either SO42- or HOSO3- is present. If HSO4- is present then SO42- is present. iii. To determine which is present we need to find the pH using indicators. If is has a pH of 2 HSO4 is present. If it has a pH of 4 then SO4 is present. iv. Indicators used: Bromythl Blue, Methyl Orange, and Methyl Violet.
c. NO3- Test
i. Place a few single small crystal of Fe(OH2)6(H4N)2(SO4)2 in a shallow watch glass. Cover the crystals with the unknown solution. Then immediately add excess drops of 18 M H2SO4 . ii. If a brown precipitate forms then NO3- is present.
VIII. Insoluble Test
a. Treat with 1M HCl
i. If it dissolves perform flame test
1. Red / Red Orange flame: Ca(OH)2
2. No color: Mg(OH)2 ii. If it dissolves with bubbles perform flame