CHMI-1006EL Study Guide - Final Guide: Calcium Oxalate, Laurentian University, Titration

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champagnewildebeest962

28 Jan 2021

School

Laurentian

Department

Chemistry & Biochemistry / Chimie et biochimie

Course

CHMI-1006EL

Professor

Caron Franﾍois

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Document Summary

Tutorials practice problems (titrations and stoichiometry: a calibrated solution of sodium hydroxide (naoh) is titrated with nitric acid (hno3) of unknown concentration. Sodium hydroxide, 75. 0 ml; concentration = 0. 125 m; Answer: c2h5 (redox balancing, titrations and stoichiometry: a sample of calcium oxalate (cac2o4) is dissolved in excess acid, followed by its titration with permanganate according to this reaction (unbalanced): Was used to completely titrate the oxalate, what is the mass (aq) + co2(aq) + h2o(l) (limiting reagent and stoichiometry: 5. 0 g of iron is reacted with 5. 0g of water according to the chemical equation shown below. 3 fe(s) + 4 h2o(l) fe3o4(s) + 4 h2(g: calculate the amount of fe3o4 produced, in grams. Chmi 1006e practice problems for mid-term 2015. docx (balancing redox reactions: balance the following redox reactions, taking place in acidic conditions. In each case, indicate which element is reduced, which element is oxidized. Reaction 2: no3 (aq) + zn(s) nh4 (aq) + zn2+ (aq)

Related Questions

1.) average number of moles of NaOH dispensed

2.)average concentration of the acid (mol/L)

3,) Based on your coarse titration volume, do you expect the acetic acid solution to have a higher or lower concentration than the NaOH solution?

higher could you please tell me if number 3 is right

please help with these 2 questions

Part 1: Prepare the NaOH Solution

Lab Results

How many mL of water were used to prepare the NaOH solution?

200mL

Data Analysis

Calculate the molarity of the NaOH solution. The molar mass of NaOH is 39.997 g/mol.

0.1M

Calculate the amount of benzoic acid to be neutralized by 20.00 mL NaOH solution, in both moles and grams. The molar mass of benzoic acid is 122.12 g/mol.

1.207 g

Part 2: Perform a Coarse Titration

Lab Results

Record the following data from your course titration in the table below.

mass of benzoic acid used (g)	0.26614g
pH of benzoic acid solution before titration	2.96
volume of NaOH in the burette before titration (mL)	50.0mL
volume of NaOH in the burette after titration (mL)	28.89mL
volume of NaOH dispensed in the titration (mL)	21.11mL

Data Analysis

How do you expect your coarse titration volume to compare to your fine titration volumes?

I expect the values to be a little off from each other since in the first titration we let out a lot at a time and didnt slowly do the titration. should only be off by a few mL.

Part 3: Perform Fine Titrations

Lab Results

Record the volume of NaOH solution dispensed in the 3 fine titrations.

20 mL dispenced ,20.34mL, 20.30mL

Data Analysis

Calculate the average concentration of the NaOH solution, using the average volume of NaOH solution dispensed in the 3 fine titrations. Report your answer using enough significant figures to distinguish it from the expected concentration of 0.100 M.

V = (V₁ + V₂ + V₃) / 3

V = (20.03 mL + 20.06 mL + 20.02 mL) / 3 = 20.04 mL

M = n / V = 0.00200 moles / 0.02004 L = 0.0998 M

Learning objective: Determine the concentration of a solution.

20.21= ----> 0.0999M

Experiment 2: Use the Standardized NaOH Solution to Determine the Concentration of an Acid

Part 1: Perform a Coarse Titration

Lab Results

What was the pH at the end point of the coarse titration?

3.87ph

Data Analysis

Based on your coarse titration volume, do you expect the acetic acid solution to have a higher or lower concentration than the NaOH solution?

higher

Part 2: Perform Fine Titrations

Lab Results

For the 3 fine titrations of the acid of unknown concentration, fill in the following data.

	Titration #1	Titration #2	Titration #3
volume of acid (mL)	59.11	40.97	40.98
volume of NaOH dispensed (mL)	9.05	9.03	9.02

Data Analysis

Calculate the following quantities and record the data in the table below.

average volume of NaOH solution dispensed (mL)	9.03
average number of moles of NaOH dispensed
average concentration of the acid (mol/L)

Conclusions

Phenolphthalein is pink over the range of pH 8 â 12. Why was it a useful indicator of when the equivalence point was reached?

This was helpful because once I got to the ph of 7 I knew that I would be getting closer to the end point which would change the color to pink.

Suppose a student titrated a sample of monoprotic acid of unknown concentration using a previously standardized solution of NaOH.

volume of 0.125 M NaOH dispensed	24.68 mL
volume of acid solution	50.00 mL

Given the data in the figure above, what is the concentration of the unknown acid?

0.0617M

Lab NOTES:

ex1

Take sodium hydroxide from the Materials shelf and add 0.800 g to the beaker.

Take water from the Materials shelf and add 200 mL to the beaker.

Ph 2.96

inital volume in burett

inital volume 50ml

1.) volume43.78mL

volumes dispenced =6.22ml

2. volume =38.05

volume dispenced =11.95ml

3.)volume = 32.06

volume dispenced=17.94

4.28.89ml

volume dispenced=21.11ml

ph=10.95

--------------------------------------

Ex 2

inital ph= 2.96

volume30.33

dispence 20.05

1. volume 39.92ml

volume dispenced=10.08

2.volume 29.66

voiume dispence 20.34

final ph10.43

initial valume in burett 50ml

--------------------

ex3

final ph9.43

volume 30.28

volume dipenced=20.00

----------------------------------------------------------------------

2nd Ex

initial ph 3.11

volume 50

1. volume 48.95mL

dispenced 1.05mL

ph 3.87

2. volume 45.88

dispenced 4.12

ph 4.67

3 volume 42.99

dispenced 7.01

ph 5.29

4 volume 39.93

dispence 10.07

ph 11.45

--------------------

final ph 9.99

volume 59.11

dispenced 9.05

ph 9.59

volume 40.97

dispenced 9.03

ph 9.50

volume 40.98

9.02

1. How many grams of NaCl are required to prepare 500. ml of 1.20M NaCl solution?

2. ) Write the balanced equation for the reaction that occurs when sulfuric acid, H2SO4 is titrated with the base, sodium hydroxide, NaOH. Sodium sulfate, Na2SO4 is the salt produced.

3. SO2 gas is in a 2.0L flask at STP (0 o C, 1 atm).

A. Using the Ideal Gas Law, determine the concentration of the gas in moles/L

B. Calculate the density of the gas in g/L.

4. You burn 150.0g C4H10O in 320.0g O2. The unbalanced equation for the reaction is :

C4H10 + O2 --> CO2 + H2O

A. Balance the equation

B. How many moles of each reactant are you starting with?

C. How many moles of CO2 may actually be produced? Note: determine the limiting reactant?

D. After the reaction is run, it is determined that 220.0g CO2 are actually produced. What is your percent yield?

5. A 1.00M solution of Ba(OH)2 is used to titrate a solution of H3PO4 of unknown concentration. At the end of the titration itâs found that 42.00 ml of Ba(OH)2 and 40.00 ml of H3PO4 were used to reach the endpoint.

The balanced equation for the reaction is: 3Ba(OH)2 + 2H3PO4 --> 6H2O + Ba(PO4)2

A. How many moles of Ba(OH)2 were used?

B. How many moles of H3PO4 are required to react with that much Ba(OH)2?

C. What is the concentration of the H3PO4 in moles/L?

6. GIven the unbalanced equation : PbO2 --> PbO + O2

A. Balance the equation

B. How many liters of O2 gas at 27o C and 1.00 atm can be made from the decomposition of 478.4g PbO2? The molar mass of PbO2 is 239.2g/mole, for O2 itâs 32.00g/mole and for PbO itâs 223.2g/mole. Hint: do the stoichiometry first. Determine how much O2 gas may be produced from 478.4g PbO2. Then determine the volume of the gas.

CHMI-1006EL Study Guide - Final Guide: Calcium Oxalate, Laurentian University, Titration

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