Week 6b Lab Gravimetric Analysis Pre-Lab Quiz

How long (in seconds) does it take for the concentration of A to decrease to 0.00800 M? Enter your answer with one decimal place and no units. 1/[A] 120 100 80 60 40 20 0 0 10 20 y = 0.7957x + 61.714 R² = 0.9998 30 Time (sec) 40 50 60

Based on this student data, calculate the average molarity of the NaOH solution. Standard: KHP = potassium hydrogen phthalate, MM 204.4 g/mol Student Data Trial 1 E KHP mL initial: NaOH mL final: NaOH 2.02 0.57 19.25 Trial 2 2.05 19.25 39.80 Trial 3 1.99 1.65 20.75

You want to make a solution of the primary standard sodium oxalate. It has a molecular mass of 133.999 g/mol (no error). Your analytical balance has an error of 0.2 mg. You add some weighing paper to the balance and it reads a mass of 0.23626 g. You then add sodium oxalate onto the weighing paper until the mass registers as 2.8539 g. You carefully transfer this to a 250.0 ml volumetric flask with an error of 0.1 ml and dissolve the sodium oxalate in a sufficient volume of water. What is the concentration of the oxalic acid (in M) and what is the absolute error (also in M).

Please answer Parts 2 and 3

please highlight the correct answer

A student performed titration to find the concentration of acetic acid. Titrant was sodium hydroxide. He went beyond the indicator color change by adding too much titrant. How will his experimental error affect the calculated value for the concentration of unknown acetic acid? calculated value actual value. calculated value < actual value calculated value = actual value. more information is necessary this is not a source of error

Based on the analysis of a vinegar solution via titration with 0.1 M NaOH. Results are as follows: Trial 1 Volume of vinegar solution used (mL) 5.00 Final burette reading (mL) 44.20 Initial burette reading (mL) 0.00 Determine the percentage mass of acetic acid in vinegar for Trial 1. The density of vinegar is 1.01 g/mL and molecular mass for acetic acid is 60 g/mol.

The following volumes of 0.000300 M SCN- are diluted to 15.00 mL. Determine the concentration of SCN- in each sample after dilution. These values will be used during the experiment.  Sample 0.000300 M SCN- (mL) [SCN-] (M) 1  1.50   2 3.50   3 7.00   4 10.00

During a lab on qualitative analysis, an unknown solution containing one cation was analyzed and the following data was collected: Anions Added to the Unknown Solution S²- SO4²- OH CO3²- Which one of the following cations is found in the unknown solution? CATIONS Ba2+ Ca²+ Sr²+ High Solubility (aq) Observation Be2+ Mg2+ no precipitate precipitate precipitate precipitate Cl, Br, I- Halides Ag+, Pb²+, Low Solubility Tl+, Hg₂²+, (s) Hg, Cu Most S2- Solubility Table Group 1, NHÀ, Group 2 Most ANIONS OH Group 1, NH4*, Sr²+, Ba²+, Tl Most SO4²- Most Ag+, Pb²+, Ca²+, Ba²+, Sr²+, Ra²+ All Group 1 compounds, including acids, and all ammonium compounds are assumed to have high solubility in water. CO3²-, C₂H3O2 NO3 PO4³-, SO3²- Group 1, Most All NH4* Most Ag+ None

Lab 8

A student creates a calibration plot for serial dilutions of Cu(NO3)2. A graph of concentration in M (x-axis) versus absorbance (y-axis) gives a linear trendline of y = 0.345x - 0.11. e.) Copper(II) nitrate has a solubility of 83.5 g in 100 g of water. Calculate the percent error in the student's concentration.

Based on this. What was the percentage error in the percentage of water in the sample, compared to pure MgSO4•7H2O?

How do I fill this out?

8 - 14 please

1. Develop a detailed separation scheme for the separation and determination of the percent composition of your sample which will be a mixture of NaCl, NH.CL, and sand. You are expected to use the properties of the components listed below and some of the techniques listed in the table in the pre-lab queries (and used in Separations I). Keep in mind that any chemistry student should be able to pick up your scheme, understand it, and use it to complete the separation and calculation of % composition. Place the scheme on a separate sheet of paper. Component Solubility (@25°C) Melting Point Hardness sodium chloride, NaCl 35 g/100 mL water 801°C soft ammonium chloride, NH&Cl 37 g/100 mL water sublimes 350°C soft sand, SIQ2 insoluble 1600°C hard Example of compounds in a container. Naci NH.CI sio2 Exploring the Chemical World, PGCC, 2003 4 RESULTS Show all calculations with units in this space.

When coming to the aid of a laboratory accident victim, you should evaluate the situation first before rushing in.     true   false

Don

The toxicity of DDT (C14H9Cl5) led to a ban on its use in the United States in 1972. Determinations of DDT concentrations in groundwater samples from Pennsylvania between 1969 and 1971 yielded the following results:  Location Sample Size Mass of DDT Orchard 253 mL 0.0310 mg Residential 1.77 L 0.0350 mg Residentialafter a storm 51.5 mL 0.570 mg Express these concentrations in millimoles per liter.   Orchard= ___mmol/l Residental=___ mmol/l Residential after a storm=___  mmol/L

Use your average AA concentration to calculate the mass percent of acetic acid in vinegar.

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

5. If the label on the bottle lists the citric acid content as 1 g per serving with a serving size of 240 mL determine the percent error in the titration results. Express result with 2 significant figures.

Can someone please help?

Which analytical separation technique is suitable to separate dissolved heavy metals from rivers. Explain how you will use the chosen technique to separate the heavy metals from the river