(a)
Interpretation:
The given data needs to be plotted using the spreadsheet including the least-squares line assuming a linear relationship between instrument reading and concentration.
Concept introduction:
The quality of water can be measured by turbidity. The degree in which the transparency of water is lost is known as turbidity. Ther higher the suspended solids, the higher is the turbidity of the water. It is measured by turbidimeter and the unit is Nephelometric Turbidity Units.
(b)
Interpretation:
The slope and intercept of the straight line from the graph needs to be determined.
Concept introduction: The quality of water can be measured by turbidity. The degree in which the transparency of water is lost is known as turbidity. Ther higher the suspended solids, the higher is the turbidity of the water. It is measured by turbidimeter and the unit is Nephelometric Turbidity Units.
(c)
Interpretation:
For the slope and intercept of the graph, standard deviation needs to be determined.
Concept introduction:
The quality of water can be measured by turbidity. The degree in which the transparency of water is lost is known as turbidity. Ther higher the suspended solids, the higher is the turbidity of the water. It is measured by turbidimeter and the unit is Nephelometric Turbidity Units.
(d)
Interpretation:
The concentration of the sulfate in the sample at turbidimeter reading 3.67 needs to be determined. The absolute standard deviation and coefficient of variation needs to be calculated.
Concept introduction:
The quality of water can be measured by turbidity. The degree in which the transparency of water is lost is known as turbidity. Ther higher the suspended solids, the higher is the turbidity of the water. It is measured by turbidimeter and the unit is Nephelometric Turbidity Units.
(e)
Interpretation:
Assuming 3.67 as mean of six turbidimeter readings, the calculations in part (d) needs to be repeated.
Concept introduction:
The quality of water can be measured by turbidity. The degree in which the transparency of water is lost is known as turbidity. Ther higher the suspended solids, the higher is the turbidity of the water. It is measured by turbidimeter and the unit is Nephelometric Turbidity Units.
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Chapter A1 Solutions
Principles of Instrumental Analysis
- The weak monoprotic acid, acetic acid, is titrated with the strong base, potassium hydroxide as follows: HC2H3O2(aq) + K+ OH- (aq) → K+ C2H3O2-(aq) + H2O(l) Ka for acetic acid is 1.81 x 10-5 (at 25 oC). A 25.00 mL sample of a solution of acetic acid with concentration 0.0833 M is titrated with 0.1000 M KOH. A. What is the pH at the beginning of the titration, Vbase = 0.00 mL? B. What is the pH at the equivalence point? C. What is the pH of the titration when 5.00 mL of base have been added? D. What is the pH when the volume of base added equals half the volume of the equivalence point? E. What is the pH of the titration when 20.00 mL of base have been added? F. What is the pH of the titration when 30.00 mL of base have been added?arrow_forwardA two-liter sample of mineral water was evaporated to a small volume, following which the potassium ion was precipitated with excess sodium tetraphenylboron: K+ NaB(C,Hs)4 → KB(CHs)4 ) The precipitate was filtered, washed and redissolved in acetone. The analysis was completed by a Mohr titration that required 43.85-mL of 0.03941M AGNO3: KB(C,Hs)4 19 + Ag → AgB(CHs)« co) + K** Calculate the potassium ion concentration (parts per million) of the water sample. Molar Mass: K = 39.10arrow_forwardCalculate the molar concentration barium hydroxide solution if it was standardized against 0.1112 g of primary-standard-grade benzoic acid, C6H5COOH (MM= 122.12 g/mol). An end point was observed after addition of 39.85 mL of base.arrow_forward
- Complete the following solubility constant expression for Ag₂ CrO4. K₁₁ = 0 sp X 0 3 Sarrow_forwardOxalic acid forms a precipitate with calcium ion Ca2+ (aq) + C2H204(ag) + H20(1) -> CaC2O4*H20 (s) + 2 H* (ag). The Ksp for calcium oxalate is 1.3 x 10^-8. A solution is prepared that initially contains 0.04 moles of Ca2+ and 0.04 moles of oxalic acid in 0.100 L of water. Based only on the Ksp value, how many moles of Ca2+ are in solution when equilibrium is reached? Using Le Chatelier's principle, suggest two things you could do, that would reduce the amount of Ca2+ remaining in solution.arrow_forwardExplain the difference between 'stoichiometric (equivalence) point' and 'end point' in the context of a titration.arrow_forward
- PREPARATION OF CHEMICAL REAGENTS As an intern in a research laboratory, you were asked to assist a researcher working on the characterization of pathogens found in a domestic wastewater sample. Specifically, you were tasked to prepare 350mL of a solution that will be used to resuspend and extract specific components from the pelleted slew of pathogens. The extraction solution is composed of 0.75 M phosphate buffer pH 8.0 (Ka2 = 6.2 × 10–8), 1.25 M CaCl2, 0.5% (w/v) SDS (sodium dodecyl sulfate), and 2.5mg per mL proteinase K. The following solutions/reagents are available in the lab in sufficient amounts: 5.0 N CaCl2 solution SDS powder (MM=288.38 g/mol) 20mg/mL proteinase K stock solution 3N HCl and 2M NaOH solutions solid NaH2PO4 (MM=119.98 g/mol) and Na2HPO4 (MM=141.96 g/mol) Calculate the amount of reagents needed in order to prepare the desired components of the extraction solution. Show complete calculations and box your final answers.arrow_forwardTue Apr 11 TA ... B HO + 1. Write the chemical reaction for the titration of the filtered KHT solution in pure water.arrow_forwardSelect the correct mass balance equation for a saturated solution of CaCl₂ assuming that the ionic species are Ca²+, Cl-, CaCl and CaOH+. (A) (B) (C) (D) O O (A) (B) (C) (D) [CH]+[CaCl] = 2[Ca²+] + 2[CaCl*] + 2[CaOH*] [CI] + [CaCl] = 2 [Ca²+] + [CaCl*] + [CaOH*] [CI]+[CaCl] = [Ca²+] + [CaCl+] + [CaOH+] [CI] = [Ca²+] + [CaOH+]arrow_forward
- Phosphate-buffered saline (PBS) is a solution commonly used in studies of animal tissues and cells. Its composition is 137 mM NaCl, 2.7 mM KC1, 10 mM Na, HPO, (pK, = 2.14), and 1.8 mM KH₂PO, (pK, = 6.86). Calculate the pH and osmolarity of PBS. Give the osmolarity in units of osmoles per liter (osm/L). pH = 7.605 osmolarity 313.0 Incorrect osm/Larrow_forward(5) a) A nitrous acid/sodium nitrite buffer solution is prepared. 20.0 mL of 6.50 M nitrous acid (HNO2) and 8.52 g of sodium nitrite (NaNO2, molar mass 68.99 g/mol) are placed in a 250. mL volumetric flask. The flask is filled to the mark with water and inverted 10 times to mix thoroughly. What is the pH of this buffer? Take Ka for Nitrous Acid to be 4.52 x 10-4. pH: b) 2.00 mL of a 2.50 M solution of NaOH is added to 75.0 mL of the buffer prepared above. What is the pH of this solution? How much did the pH change? pH: change in pH: c) What is the pH of pure distilled water (just give the pH, no calculations are necessary). d) If 2.00 mL of 2.50 M…arrow_forwardA student is calculating the concentration of her standard solutions in order to create the calibration curve (standard curve). Calculate the equilibrium isothiocyanatoiron(III) ion concentration, [FeNCS²+]eq, for a solution created by combining 2.00 mL of 0.183 M Fe3+ (aq) with 225μL of 0.00199 MSCN- (aq). Give your answer to three decimal places. Also give your answer in millimolar (mM) (because you won't be able to enter an answer in scientific notation here). You may assume that the volumes of these dilute, aqueous solutions are additive.arrow_forward
Principles of Modern ChemistryChemistryISBN:9781305079113Author:David W. Oxtoby, H. Pat Gillis, Laurie J. ButlerPublisher:Cengage Learning
Chemistry: The Molecular ScienceChemistryISBN:9781285199047Author:John W. Moore, Conrad L. StanitskiPublisher:Cengage Learning