13. The calibration curve for spectrophotometric determination of phosphorus is shown below. The relationship between the absorbance and the concentration of phosphate in mg/L is given in the figure as well. Calculate the concentration of phosphate if a wastewater sample gives an absorbance of 0.660. 1.0 A. 12.6 mg/L В. 12.8 mg/L C. 13.0 mg/L D. 13.2 mg/L 13.4 mg/L y = 0.0515x – 0.0221 0.8 R = 0.997 0.6 Е. 0.4 0.2 0.0 4 12 16 20 Concentration of phosphate (mg/L) Absorbance at 470 nm
Ideal and Real Gases
Ideal gases obey conditions of the general gas laws under all states of pressure and temperature. Ideal gases are also named perfect gases. The attributes of ideal gases are as follows,
Gas Laws
Gas laws describe the ways in which volume, temperature, pressure, and other conditions correlate when matter is in a gaseous state. The very first observations about the physical properties of gases was made by Robert Boyle in 1662. Later discoveries were made by Charles, Gay-Lussac, Avogadro, and others. Eventually, these observations were combined to produce the ideal gas law.
Gaseous State
It is well known that matter exists in different forms in our surroundings. There are five known states of matter, such as solids, gases, liquids, plasma and Bose-Einstein condensate. The last two are known newly in the recent days. Thus, the detailed forms of matter studied are solids, gases and liquids. The best example of a substance that is present in different states is water. It is solid ice, gaseous vapor or steam and liquid water depending on the temperature and pressure conditions. This is due to the difference in the intermolecular forces and distances. The occurrence of three different phases is due to the difference in the two major forces, the force which tends to tightly hold molecules i.e., forces of attraction and the disruptive forces obtained from the thermal energy of molecules.
Please answer all 3 questions
![**Transcription for Educational Website:**
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**Question 13:**
The calibration curve for spectrophotometric determination of phosphorus is shown below. The relationship between the absorbance and the concentration of phosphate in mg/L is given in the figure as well. Calculate the concentration of phosphate if a wastewater sample gives an absorbance of 0.660.
**Options:**
- A. 12.6 mg/L
- B. 12.8 mg/L
- C. 13.0 mg/L
- D. 13.2 mg/L
- E. 13.4 mg/L
**Graph Description:**
- The graph plots "Absorbance at 470 nm" on the vertical axis against "Concentration of phosphate (mg/L)" on the horizontal axis.
- A linear trend line is displayed with the equation: \( y = 0.0515x - 0.0221 \).
- The \( R^2 \) value of 0.997 indicates a strong linear correlation.
---
**Context:**
A large mine on the island of Cebu in the Philippines was in operation from 1953 until 1994. When the mine closed, it left behind waste rock, tailings, open pits, and landfills that are leaching lead toxins into the environment. In 2006, mining operations re-commenced, and are also responsible for lead pollution in the area. One water sample immediately above river sediment was collected and analyzed. Answer Questions 14 & 15.
**Question 14:**
If the water sample contained 15,231 ppm of lead, what was the molar concentration?
**Options:**
- A. \( 3.77 \times 10^{-6} \) M
- B. \( 3.77 \times 10^{-2} \) M
- C. \( 7.35 \times 10^{-2} \) M
- D. \( 7.35 \times 10^{-5} \) M
- E. \( 1.52 \times 10^{4} \) M
---
**Question 15:**
Determine pE for the water sample. Does this water favor oxidation or reduction?
- Reaction: \( \text{Pb}^{2+}(\text{aq}) + 2e^- \rightarrow \text{Pb(s)} \)
- Standard Electrode Potential (\( E^\](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F9269888f-6fb9-4d4f-8484-919fffe14161%2F091c8fc6-a3b4-4942-96ee-7c5439cf6777%2Fkvkg22g_processed.jpeg&w=3840&q=75)
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