# 2. A student wants to determine the concentration of phosphate ions in 20.0 mL of water. He prepares 4solutions that contain a known amount of phosphate as shown in Table 1. He mixes these solutions plus thesample of water with HzSO4, ammonium molybdate and ANSA. The results are shown in Figure 1 below. Thefinal volumes of all tubes are identical.TABLE1| Amount of Phosphate (umoles)030.045.0100.0Solution #4Solution #1Solution #2Solution #3Solution #4Sample of drinking waterFigure 1: The phosphate standard solutions and the sample of drinking water after theaddition of H2SO4, ammonium molybdate and ANSAa) How many umol of phosphate ions are present in the drinking water sample? (Show calculations.) Theamount of phosphate will need to be approximated if the intensity of the sample is between the intensities oftwo standards. Because the final volumes are all identical, an identical intensity indicates an identical # ofumoles.b) What is the concentration in micromolarity of the phosphate in the water sample?

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Im having difficulty with part A and B of this homework problem, thanks in advance help_outlineImage Transcriptionclose2. A student wants to determine the concentration of phosphate ions in 20.0 mL of water. He prepares 4 solutions that contain a known amount of phosphate as shown in Table 1. He mixes these solutions plus the sample of water with HzSO4, ammonium molybdate and ANSA. The results are shown in Figure 1 below. The final volumes of all tubes are identical. TABLE1 | Amount of Phosphate (umoles) 0 30.0 45.0 100.0 Solution # 4 Solution #1 Solution #2 Solution #3 Solution #4 Sample of drinking water Figure 1: The phosphate standard solutions and the sample of drinking water after the addition of H2SO4, ammonium molybdate and ANSA a) How many umol of phosphate ions are present in the drinking water sample? (Show calculations.) The amount of phosphate will need to be approximated if the intensity of the sample is between the intensities of two standards. Because the final volumes are all identical, an identical intensity indicates an identical # of umoles. b) What is the concentration in micromolarity of the phosphate in the water sample? fullscreen
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Step 1

a) From the given figure, the intensity of water sample is between the intensities of solution 3 and 4. Thus, the concentration of phosphate ions in the water sample lies somewhere in between that of the solutions 3 and 4. Thus, the amount of phosphate ions in water sample may be calculated as:

Step 2

b) Molarity is defined as the number of moles of solute per liter of the solution.

The volume of water sample is 20 mL. K...

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