4.A student carried out a simple distillation on a compound known to boil at 124°C and measured a boiling point of 116-117°C. Gas chromatography(a technique for assessing purity)showed that the compound was pure and a calibration check on the thermometer was positive. What might be wrong with the distillation apparatus setup?

Starting from the primary standard solution in Question 4 and using the dilution scheme in Figure 1, calculate the concentrations of Standards #1-5. Show all work on a piece of scratch paper. Label each calculation clearly (Standard #1, Standard #2, etc) and circle your final answer for each standard. Be sure to round your answers to the correct number of significant figures and include units. Molarity in #4 is 0.0004089 M or 4.089x10^-4

Based off information from the attachment, please help with #9 on second attachment

A stock solution of 0.225 +/- 0.003 M NaNO2 was transferred to a 100 mL volumetric flask (class A) and diluted to the mark.  If 7 mL of the stock solution was transferred using one 5-mL and two 1-mL volumetric pipettes, what is the new concentration of the solution and the uncertainty?

Six 50.0 ml volumetric flask 1 through 6 are labeled. 10.00 ml of 2.00 x 10-1 M Fe(NO3)3 solution was then pipet into each volumetric flask. A 1.00,2.00,3.00,4.00 and 5.00ml of 2.00 x 10-3M NaSCN solution was then pipetted to flask 2 through 6 respectively. A sufficient amount of 0.10 M nitric acid was then added to each flask to make each a total volume of 50.00ml. Hint M1V1=M2V2 a)what would be the concentration of Fe(NO3)3 in 0.10M HNO3? b)what would be the concentration of NaSCN in 0.10M HNO3?

You are analyzing the effluent from a lotion plant for parabens using HPLC. You have a working standard solution with a concentration of 59.4 ppm which returned a Peak Height of 10,164 and Peak Area of 5,315. You take 44.4 L of the water sample and concentrate it to 0.3 L and analyze this solution. The Peak Height is 9,119 and the Peak Area is 6,320. What is the concentration of parabens in the effluent of the plant in mg/L to two decimal places.

One milliliter (mL) of pure water has a mass of 1 gram (g). You add 100 mL of water and 100 mL of an organic solvent to a separatory funnel, shake, and let settle. There will be two layers of liquids. Select the one solvent listed below that will result in the water layer being the top layer. For each solvent, density (d) is given in g/ml. Toluene (d = 0.86) Tetrahydrofuran (d = 0.88) water is never the top layer Methylene chloride (d = 1.33)

A 25mL volumetric pipet is used to deliver a sample of the stock solution marked “0.6000M X2SO4” into a 100mL volumetric flask. Distilled water is added to the flask until it is about 3/4thfull, the solution is mixed well, then more water is added to fill it up to the calibration mark, then it is mixed again. Calculate the concentration of X+ion in the dilute solution made above.

What is the absolute uncertainty and relative uncertainty of the molarity of the solution?   M =  = 0.078376462 = 0.078 M Pb2+

You measure 15.0 mL of the H2C2O4 solution with a 100-mL graduated cylinder and add it to a 125-mL Erlenmeyer flask.  Then you add two drops of the indicator, phenolphthalein, to the oxalic acid solution in the flask.  You dispense the NaOH solution from the buret into the flask (while swirling the flask) until you reach the endpoint.  At the endpoint, the solution in the flask turns light pink.  You repeat the titration two additional times for a total of three trials.  H2C2O4 (aq) + 2 NaOH (aq) --> Na2C2O4 (aq) + 2 H2O (l)                                                (I)              (II)                (III) Volume of H2C2O4 used  15.00 mL   15.00 mL   15.00 mL how many Moles H2C2O4 are used in each trial?