Scientists can learn a great deal about a community's drug use (both legal and illegal) by analyzing the contaminants in wastewater. In a recent study in New York State, chemists measured the concentration of cotinine, a derivative of nicotine that i produced in the liver and excreted in the urine of tobacco users. The chemists found the average cotinine concentrations in the wastewater stream was 1.43 µg/L. a Ι Ι H- b HH H H-C C-N: C=0: TH HH Jonutis/Shutterstock Revell, Introductory Chemistry, 2e, © 2021 W. H. Freeman and Company Cotinine is slightly soluble in water. Using the structure of cotinine, identify any polar covalent bonds that are present in this substance. C-O C-C C-H C-N

Alcohol levels can be determined by reaction with dichromate (breathalyzer). C2H5OH(l) + 2 Cr2O72-(aq) + 16 H+(aq) → 4 Cr3+(aq) + 11 H2O(l) + 2 CO2(g) What is the alcohol level expressed in parts per thousand of a blood plasma if a 32.6 g sample of plasma requires 21.27 mL of a 0.02226 M solution of K2Cr2O7 for complete reaction?

Write a procedure that a laboratory technician could use to prepare 2.0 L of 0.25 mol/L sulfuric acid, H2S04(aq), using 12.0 mol/L stock solution. Include appropriate safety precautions.  Hypochlorous acid, HOCl(aq), is a weak acid that is used as a bleach and a disinfectant. When 25.00 mL samples of hypochlorous acid were titrated with 1.00 mol/L sodium hydroxide, NaOH(aq), an average of 19.15 mL of sodium hydroxide was needed to neutralize the acid. Calculate the molar concentration of the hypochlorous acid.

There is a legend according to which a young man presented his beloved with a ring made of iron. Iron was obtained from the blood of a young man.a) Estimate how long it took the young man to excrete the required amount of iron from his blood. The boy's body weight is 80 kg. Blood makes up 8% of a person's weight, the density of blood is 1.050 g / ml, 100 g of blood contains 14 g of hemoglobin. The molar mass of hemoglobin is 68kg / mol (take into account the number of iron atoms in all subunits!).According to the rules for donating blood for men, it is safe to donate blood no more than 4-5 times a year (for calculations, use 4 times). During one collection, 450 ml is taken.b) To isolate iron from the blood, the blood was first centrifuged to separate hemoglobin, thenthe protein was destroyed with acid (that is, you have a solution containing iron cations).Suggest a further chain of reactions to obtain metallic iron. (write the reaction equations)  take the mass of the ring 3 g

A chemist needs to create a series of standard Cu²+ (aq) solutions for an absorbance experiment. For the first standard, he uses a pipet to transfer 10.00 mL of a 2.07 M Cu²+ (aq) stock solution to a 500.0 mL volumetric flask, and he adds enough water to dilute to the mark. He then uses a second pipet to transfer 5.00 mL of the second solution to a 100.0 mL volumetric flask, and he adds enough water to dilute to the mark. Calculate the concentration of the Cu²+ (aq) solution in the 100.0 mL volumetric flask. concentration: M

An aqueous solution contains 2.8 mM of total ions. Part A If the solution is NaCl(aq), what is the chloride ion concentration? Express your answer as a concentration to two significant figures. ΑΣΦ E (CI ] in NaCl(aq) = mM CI (aq) %3D

A chemist prepares a solution of iron II bromide   FeBr2   by measuring out 17.mg of FeBr2 into a 50.mL volumetric flask and filling to the mark with distilled water.   Calculate the molarity of Br− anions in the chemist's solution.   Be sure your answer is rounded to the correct number of significant digits.

A chemist prepares a solution of silver(I) nitrate (AgNO,) by measuring out 245. µmol of silver(I) nitrate into a 400. mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in umol/L of the chemist's silver(I) nitrate solution. Be sure your answer has the correct number of significant digits. u mol x10

0.644 g of wood bleach, which contains oxalic acid, H2C2O4, was placed in an Erlenmeyer flask.  The wood bleach was titrated with 23.57 mL of 0.379 M KOH solution.  Determine the percent by mass of the H2C2O4 (a diprotic acid) in the sample of wood bleach. Enter your answer with the correct number of significant figures.  If you do not enter the correct number of significant figures, your answer may be graded as incorrect even if it is otherwise correct.

A chemist prepares a solution of vanadium(III) bromide (VBr) by measuring out 0.10 g of VBr3 into a 100. mL volumetric flask and filling to the mark with distilled water. Calculate the molarity of Br anions in the chemist's solution. Be sure your answer is rounded to 2 significant digits. mol L x10 X Ś