At the start, the solution have been filtered and the white precipitate was accumulated. The precipitate may be calcium mineral oxalate. The filtrate was then obtained and used for the persistence of the absorbance by using the atomic absorption spectroscopy (AAS). The absorbance of the calcium mineral filtrate is increasing little by little as the attentiveness increase steadily. As more material ion exists (attention increase little by little), they have a tendency to collide with one another easily and cause the absorbance to increase when the focus increase. Hence as concentration of the filtrate increase, the absorbance can also increase. For standard, the wavelength of calcium mineral is 422. 7 nm in the atomic absorption spectroscopy (AAS).
Chloride is an anion (oxidation point out of -1) meaning it consist of a negatively fee. Whereas calcium is a cation (oxidation status of +2) which means that it consisted of a positive charge. As calcium has the charge of +2 and chloride has the charge of -1 which is unbalanced, hence they are not stable.
In order to achieve the balance, 2 chloride ions are had a need to bind with 1 calcium mineral ion. As this happen, it'll cause chloride ion to absorb strongly as this can be seen from the high absorption value of chloride compare to others ion. The depression of chloride is less than phosphate, this might due to the charge of the 2 ions.
Chloride can be an anion and it will bind with calcium mineral to form a stable and neutral ingredient but as basic, chloride have the oxidation condition of -1 and therefore it has less energy that will generally cause it to have less absorption value. Whereas phosphate is a cation and it will bind with calcium mineral to form a stable and neutral chemical substance but as standard, phosphate possess the oxidation state of -2 and so it has more energy that will generally lead it to have more absorption value.
The phosphate ions hinder the dedication of calcium. Within the presence of phosphate ions, the absorption because of the calcium mineral is weaker when compared with that in which phosphate ions were taken out. This may due to the formation of stable phosphate of calcium mineral that does not easily split up into atoms in the flame. The suppression by phosphate was proportional up to phosphate/calcium ratio around 2:3, and it became constant. Hence, it is proportional decrease in absorption with increasing phosphate concentration.
High concentration of phosphate will have frequent interference. It is because phosphate inhibited the calcium mineral absorption firmly. As phosphate can respond with calcium ion and in the fire to produce calcium mineral pyrophosphate, Ca2P2O7 that eliminates many calcium atoms from the fire. This cause a reduction in the absorbance since the calcium must be in the atomic form to absorb its resonance lines. This sort of solution interfere can be reduced or taken away chemically. Hence, it will cause the absorption value to depress.
Absorbance of magnesium and aluminium
Magnesium
For magnesium, there are large numbers of ions was found that the calcium interference were less serious in magnesium at lower amount but much more serious at the higher attentiveness. The depression of aluminium was nonlinear and depended on the percentage of calcium to aluminium.
From the result above, you can find suppression of calcium by magnesium to a Mg/Ca proportion of 1and the absorption is constant. This implies that there can be an improvement of magnesium atoms at the free calcium atoms. The wavelength of magnesium is 285. 2 nm in the atomic absorption spectroscopy (AAS).
Aluminium
Calcium absorption is subject to lots of interference when aluminium is added to it. This may cause its indication to curb. The suppression by aluminium was substance in characteristics. This factor will respond as anions with calcium mineral to give the calcium salt which is calcium aluminate. The wavelength of aluminium is 309. 3 nm in the atomic absorption spectroscopy (AAS). However in theoretical, Al can enhance the result of interference. This condition may be induced by ionization of the aluminium itself as it included high charge. The obtained effect is totally different from the theoretical final result may be scheduled to some complex error and human being error.
Comparison between Magnesium and Aluminium
The interfere with the willpower of calcium from the aluminium is more than magnesium. This might due to the several charge and shape of aluminium and magnesium. From the result obtained, aluminium depress more compared to magnesium because aluminium have 1 extra positive charge compared to aluminium. Since it has more fee it will cause the aluminium ion to be ionized more weighed against the magnesium that is insufficient 1 positive.
On other hands, how big is the aluminium is normally bigger than magnesium. Bigger size of aluminium may cause it to own less energy set alongside the magnesium that has a smaller size. This cause aluminium to has less absorption value. As the wavelength of magnesium and aluminium in the atomic absorption spectroscopy (AAS) are almost the same, so that it is sometimes difficult to identify the absorption music group of the magnesium and aluminium in the atomic absorption spectroscopy (AAS).
Absorbance of phosphate + 1% EDTA
The absorbance of phosphate and 1% EDTA is slightly lower than the absorbance of phosphate without 1% EDTA. It is because the suppression disturbance have been get over and reduced for phosphate in today's of EDTA. When there's a high attentiveness of EDTA was added to the solution in order to create a chelate is dissociated is the fire to give free calcium vapor.
EDTA was added for the determination of calcium in order to prevent disturbance from phosphate because EDTA will protect calcium mineral from binding with phosphate. Hence, it will have a lesser absorption value than the absorption value of phosphate alone.
Absorbance of phosphate + 2000 ppm strontium
Strontium released calcium mineral completely from the international refractory metal, which is then complexed with chloride. When there's a occurrence of strontium in the phosphate, it cause the absorbance of the solution to increase, it is because strontium can overcome all the anionic interferences.
Strontium can act as a releasing agent that means that this can incorporate with the phosphate and prevent its reaction with the calcium. Hence, it will have an increased absorption value compared to the phosphate alone and the ones which contain EDTA.
Remark:
Actually for the ions, the absorption value that obtained should be all positive, but also for the result obtained experimentally for the next, 3rd, 4th and 5th are negative. This may due to some factor. The 1st factor is real human error made through the experiment such as do not add the perfect solution is follow the attentiveness properly, do not take some precaution and the answer may be polluted.
2nd factor that induced the negative value of the effect obtained may be because of the technical error such as the atomic absorption spectroscopy (AAS) that is used to determine the absorbance of the ions do not calibrate well. Besides that, that machine used might not be maintain or repair for a long time, o it will caused some inaccurate in the result that obtained.
Conclusion:
Part A:
Percentage (%) of precipitation of calcium mineral oxalate is 99. 97%.
Part B:
The amount of calcium mineral present in drinking water can be dependant on fire atomic absorption spectroscopy.
The series for the depression in the absorbance of the component is arranged in the descending order as adopted:
(more) Phosphate + 1% EDTA > Phosphate > Magnesium and Aluminium > Chloride > Phosphate + 2000 ppm Strontium (less)
