EXPERIMENTAL PROBLEM n. 11 GROUP 2
By: Tuukka, Tomi, Francesco, Paolo, Marco G.
You receive a sample of a salt formed by an "s-block" metal and an halogen. The amount of this sample contains as many halogen ions as there are in 1,00 grams of sodium chloride. You have to recognize the metal and the halogen in that salt.
Vi viene assegnato un campione di sale formato da un metallo del "blocco s" e da un alogeno. La quantità di questo campione contene tanti ioni alogenuro quanti ve ne sono in 1,00 g di cloruro di sodio. Dovete riconoscere il metallo e l'alogeno nel sale.
Saat suolanäytteen, joka koostuu alkali- tai maa-alkaliryhmän metallista (=s-ryhmä) ja halogeenista. Näyte sisältää yhtä monta halogeeni-ionia kuin 1,00 grammassa natriumkloridia (NaCl) on kloridi-ioneita. Tehtävänä on tunnistaa, mistä metalli- ja halogeeni-ioneista suola koostuu.
1. Useful knowledge (reference data, concepts and principles)
1.1 Colours of alkali metals to the bunsen flame:
| Lithium |
Sodium |
Potassium |
Calcium |
Strontium |
Barium |
| deep red |
yellow/orange |
lilac |
pale orange |
red sparkle |
green/yellow |
1.2 Atomic relative mass of sodium and chlorine: Na 22.99 Cl 35,45
1.3 Formula Weight of NaCl:58,44
1.4 Formula of a salt formed by Me+ and X- ions: MeX
1.5 Formula of a salt formed by Me2+ and X- ions:MeX2
2. Main idea
know the weight of the salt that is given us through wise to understand that the flame of metal "blocco-s" part, then by calculation are also halogen
3. Planning
1. weigh the salt in a plastic bag
2. weigh the empty container bag
3. see the color of flame from the flame test, and comparisone it with the results of previous experiments
4. How long we then calculate the atomic mass of the second element in the compound
5. compare it with the table of elements, that and find the one which comes closest nearest: we'll take it for good
4. Report
| Italian exp. done on March 29th + April 19th |
Finnish experiment done on 31.3.2010
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we took the salt assigned to us, in a tub and we weighed it
tube with salt; mass = 3.48 g
empty tub; mass = 2.10 g
We did the flame test, resulting in a lilac color.
We repeated the flame test on 19th March and we've got this pale lilac color
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Hello Tuukka, that's nice!! We had a problem, now we have two!
we took the salt assigned to us, in a tub and we weighed it
tube with salt; mass = 14,9 g
empty tub; mass = 13,5 g
salt sample mass = 1,4 g
We did the flame test, resulting in a orange color.
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5. Elaboration and Interpretation
| Italian |
Finnish |
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3.48 - 2.10 = 1.38g
The salt should be formed by potassium.
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14,9-13,5=1,4g
The salt is calcium.
Francesco, Paolo and Marco are right, the metal ion is potassium.
1g/58,44=0,01711156742
0,01711156742*39,10=0.6690622861
1,4-0.6690622861=0,7309377139
0,7309377139:0,0171=42,74489555
48,74 is closest to chlorine. Our salt is KCl
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Common conclusions
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Questions & Answers
1. Why are atoms emitting light at the flame?
Answer 1
2. How did you recognize the metal element in the salt?
Answer 2
3. What measure permitted you to deduce which halogen was in the salt?
Answer 3
4. Does your salt contain more cations or anions?
Answer 4
5. Does your salt contain more mass as halide ions or as metal ions or the same?
Answer 5
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