A group of students titrate a calcium carbonate standard solution repeatedly in five experimental trials. Based on the five trials, the group detemines that the average concentration of the standard is 80.5 ppm with a standard deviation of 0.5 ppm. Using the equation for the Student's t confidence interval found in Appendix 1 of your lab manual and the t-value for a 95% confidence interval, calculate the confidence interval for which there is a 95% chance of finding the "true value" of the standard solution's concentration based on the data. Put your answer in the fomat # lower limit < "true value" < # upper limit. (Appendix 2 has an example that may be helpful.)

Introductlon In Part (a) of this experiment you will prepare a primary standard. Potassium hydrogen phthalate (KHP) is a monoprotic acid with the formula KHC,H.O. In this experiment KHP is used as the primary standard. A standard solution is one whose solute concentration is accurately known. If a solute can be obtained in a very pure, stable, weighable form, a primary standard solution of it can be prepared directly. You will then use the standardized sodium hydroxide solution to determine the acetic acid content of a dilute unknown solution. Procedure (0) Preparation of a Primory Standard Potassium hydrogen phthalate (KHP) is a primary standard. Weigh accurately by difference, approximately 0.8 g of KHP in a clean, dry weighing bottle and transfer it into a 250 ml conical flask. Add 75 ml of distilled water. Swirl gently. Cover the flask and leave to dissolve, swirling periodicaly. Cautlon: KHP is not highly soluble and care must be taken to ensure it is all dissolved before you…

What do you call the type of analytical method that relies on the absolute stoichiometric equivalences of balanced chemical reactions in order to compute the amount of analyte present in the sample?   Oxidative methods   Instrumental methods   Classical methods   Blank Correction Methods

Solid calcium carbonate, CaCO3, was added to a solution of pure water. Analysis found 1.20*10-3 M Ca2+ ions in solution. Calculate the Ksp of CaCO3. Be sure to use 3 significant digits in your answer.

A certain drug has a half-Iife in the body of 2.5 h. What should the interval between doses be, if the concentration of drug in the body should not fall belc 40.% of its initial concentration? Round your answer to 2 significant digits.

For lab 4, we combined baking soda with vinegar, according to the chemical equation NaHCO 3 + CH 3COOH ==== NaCH 3COO + CO 2 + H 2O Consider 3 experiments: (i) 2g baking soda + 5mL vinegar, (ii) 2g baking soda + 10mL vinegar and (iii) 2g baking soda + 20mL vinegar. The amount of CO 2 produced was highest for (iii) and lowest for (i). For these experiments, which of the following is true? Vinegar ran out first Baking soda ran out first They both ran out at the same time Neither ran out

Calculate the concentration (Mdil) of potassium permanganate (KMnO4) when 600 mL (Vconc) of the potassium permanganate solution is added to 400 mL of water. Note: first add the potassium permanganate solution (choose dropper) in the absence of water, move the sensor over the solution, and determine the concentration of the solution prior to adding water (Mconc). Knowing these three pieces of data, you can now calculate (Mail), and enter this calculated number as your answer. You can also confirm your answer by adding 400 mL of water to your 600 mL of potassium permanganate solution and checking the concentration with the sensor (NOTE: the sensor concentration will likely be slightly off the calculated number since it's difficult to add exact volumes in the simulator). Please report your numerical answer only with three significant figures and NO units (eg., 1.23). Mdildil MconcVconc A R

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An analysis where we know what analytes we are looking for is called An analysis where we do not know what analytes are in the sample is called a An example is A) untargeted, confirmation, targeted, Comprehensive drug screen B) targeted, confirmation, untargeted, comprehensive drug screen C) targeted, comprehensive drug screen, untargeted, confirmation analysis. An example is analysis. ▪ True or false: The purpose of the internal standard is to make quantitation of the analyte insensitive to injection errors

Three labs were contracted to measure the concentration of a 5.50 ppm Ca2* standard solution. They each measured the solution 3 times, and their results are as follows: Measurement 1 Measurement 2 Measurement 3 Laboratory 1 5.47 ppm 5.54 ppm 5.50 ppm Laboratory 2 5.32 ppm 5.44 ppm 5.56 ppm Laboratory 3 5.61 ppm 5.62 ppm 5.60 ppm Select ALL of the TRUE statements about the measurement capabilities of these labs. Lab #3 was the most precise. Lab #1 was the most precise. Lab #1 was the most accurate. Lab #2 was the most precise. O.Lab #2 was the most accurate. Lab #3 was the most accurate.