Pure solid NaH2PO4 is dissolved in distilled water, making 100.0ml of solution.

Question

Pure solid NaH2PO4 is dissolved in distilled water, making 100.0ml of solution. 10 ml of this solution is diluted to 100.00 ml to prepare the orignal phosphare standard solution. Three working standard solution are made from this by pipetting into 0.8 ml, 1.5 ml and 3.0 ml of the orignal standard solution into 100.0 ml volumetric flasks. Acid and molybdate reagent are added and the solution are diluted to 100.0 ml. phosphate in the soft drink. You may assume that all these absorbance measurements have already been corrected for any blank absorbance. The absorbance of each is measured in the spectrophotometer. A 10.0 ml volume of soft drink is treated with acid and reagent and also diluted to 100.00 ml. Its absorbance is also measured. From the following data, plot a calibration line (absorbance vs. concentration), determine its slope and calculate the concentration of phospate in the original soft drink(mM).

Data given:

Mass of NaH2PO4 (mg) -- 536.4

Absorbance standard 1 (0.8 ml) -- 0.1973

Standard 2 (1.5 ml) --- 0.3701

Standard 3 (3.0 ml) --- 0.7402

sample (10.0 ml) -- 0.2230                                                                               

Concentration of orignal phosphate standard (mM) 4.47

concentration of standard 1(mM)   -- 0.03576

concentration of standard 2(mM) -- 0.06705

concentration of standard 3(mM)   -- 0.1341                         

Slope of calibration line -- 5.522

Need help with the following question:

calculate the concentration of phospate in the original soft drink(mM).

Calculated answer so far is wrong:   x=0.04042 mM

Explanation / Answer

bro is the answer 0.4042 mM ?

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

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