A student was given five labeled solutions: NiCl2 , Pb(NO3)2 , NaOH , Na2C2O4 , and CuSO4 .  After mixing these solutions in pairs, the student recorded her observations on Table 3.  She was then given five labeled solutions: A, B, C, D, and E.  After mixing these solutions in pairs, the student recorded her observations on Table 4.  The one thing that she does know about these solutions is that the unknowns are the same solutions as the knowns.  So what are the five unknown solutions, i.e. list out A= , B= , C= , D= , E= . Table 3: KNOWNS XXX CuSO4 Na2C2O4 NaOH Pb(NO3)2 NiCl2 NR, blue green solution NR, green solution green ppt, green solution NR, green solution Pb(NO3)2 white ppt, blue solution white ppt, clear colorless solution white ppt, clear colorless solution XXX NaOH blue ppt, blue solution NR, clear colorless solution XXX XXX Na2C2O4 white ppt, blue solution XXX XXX XXX   Table 4:  UNKNOWNS XXX E D C B A blue ppt, blue solution white ppt, clear colorless solution NR, clear colorless solution green ppt, green solution B NR, blue green solution NR, green solution NR, green solution XXX C white ppt, blue solution white ppt, clear colorless solution XXX XXX D white ppt, blue solution XXX XXX XXX

Most analytical machines used in science can either measure absorbance of light, like the spectrophotometers used BioZ 151 and 152 labs, or can measure change in electrical conductance. In order to convert things like absorbance values into concentration data, a linear regression is used. In order to determine nitrite concentration in water samples, nitrite is reacted with several chemicals to produce a purple color. The absorbance of the solution is measured from known amounts of nitrite to produce a standard curve to analyze samples. Use the data in the provided table, or from the linked spreadsheet to make a graph and perform a linear regression using treadline. mg/L NO3 Absorbance 0 0.1 0.3 0.5 0.7 o 0.183 0.542 0.914 1.298) 1.61) In order for this to work, samples must be diluted prior measurement so that the concentration falls within the range of the standard curve. If a sample underwent a 30 dilution, and produce an absorbance value of 0.953, what is the resultant concentration…

A student follows a lab protocol that asks them to make an ‘alcohol’ solution for an experiment. They make a 1.00 L solution by adding 575 g of an alcohol to water. Later they realize that there were three different alcohols sitting on the lab bench and they’re not sure which one they used. The alcohols are: methanol (CH3OH), ethanol (C2H5OH), and butanol (C4H9OH). They decide to boil the solution and they find that it boils at 106.40 °C. Using this information determine which alcohol the student used to make their solution. Density of water is 1.00 g/mL, Kb = 0.513 K/mc. Hint: you need to consider the molar masses of your alcohols.

An analytical chemist weighs out 0.091 g of an unknown triprotic acid into a 250 mL volumetric flask and dilutes to the mark with distilled water. He then titrates this solution with 0.1200M NaOH solution. When the titration reaches the equivalence point, the chemist finds he has added 23.2 mL of NaOH solution. Calculate the molar mass of the unknown acid. Round your answer to 2 significant digits. mol ?