top-rated free essay

Lab 5 Acid Burn

By Nick-Wigginton Apr 15, 2015 831 Words
Experiment #5: Acid Burn!!!
Introduction
The goal of this lab was to correctly prepare a 0.2M solution of NaOH, identify highly acidic household cleaning chemicals, and determine their concentration (molarity) through titrations using the previously prepared 0.2M NaOH solution. Experimental

First, to create 0.5L of 0.2M solution of NaOH, standard 3M NaOH solution was obtained. Next, calculations were performed to determine the amount 3M NaOH necessary to create 0.5L of the 0.2M solution and, as a result, 33.333ml of the 3M solution was measured and poured into a 600ml beaker. The 33.333ml of 3M solution was then diluted with deionized H2O to a volume of 0.5L, thus theoretically resulting in 0.5L of 0.2M NaOH. Next this solution was used to titrate a sample of known mass of KHP dissolved in 40ml of deionized H2O indicator in order to determine the actual concentration of the experimental NaOH solution. Two trials of titration were conducted and the volumes of NaOH required to reach the equivalence point were recorded. Calculations yielded final concentrations for the NaOH solution of 0.1950M and 0.2005M respectively for an average concentration of 0.1977M; the experimental solution of NaOH was therefore concluded to be of sufficient quality for use in determining the concentration of the various household cleaners.

In the determination of acidic household cleaning products, seven chemicals (Drano, SnoBol, glass cleaner, Parson’s, Lysol, The Works, and Comet) were presented. Each solution’s pH was determined using pH testing strips and the results were recorded. SnoBol, Lysol, and The Works each yielded pHs of 1, the most acidic of the seven chemicals, and, therefore, were selected for the final portion of the experiment in which their concentrations would be determined.

To determine the concentrations (molarity) of SnoBol, Lysol, and The Works, 1ml of each chemical was diluted with 20ml of deionized H2O, treated with 3 drops of phenolphthalein indicator solution and titrated with the experimentally obtained 0.2M NaOH solution. Multiple titrations were performed with each chemical. Calculations were then performed to determine the concentration of each chemical from its trials and the average molarities from these trials were used to conclude the concentration of each household cleaner. SnoBol had an average concentration of 4.7M, Lysol had an average concentration of 3.1M, and The Works had an average concentration of 6.3M. Molarity of NaOH

Trial
Mass of KHP used (g)
NaOH used (ml)
Molarity of NaOH (mol/L)
1
0.6129
15.39
0.1950
2
0.6108
14.92
0.2005
Average Molarity of NaOH (M)
0.1977

Sample Calculations
Molarity of NaOH: 0.6129g KHP / (204.22g/mol) / (15.49ml/1000ml) = 0.1950 Average Molarity: (0.1950M + 0.2005M)/2 = 0.1977
pH of Household Cleaners
Cleaner
pH
Drano
11
SnoBol
1
Glass cleaner
9
Parson’s
9
Lysol
1
The Works
1
Comet
5

Molarity of Specific Household Cleaners
Product
Trial
NaOH used to titrate (ml)
Molarity of Product (mol/L)
Average Molarity of Product (g/L)
SnoBol
1
23.63
4.6724
4.6678

2
23.58
4.6625

3
23.61
4.6684

Lysol
1
15.98*
3.1597*
3.0797

2
15.56
3.0767

3
15.59
3.0826

The Works
1
33.08
6.5409
6.3162

2
31.54
6.2364

3
31.21
6.1712

*-Trial was discounted from final average because sample was overtitrated Sample Calculations
Molarity of Household Cleaner: (33.08ml/1000ml) * (0.1977g/mol) / (0.001L) = 6.5409 mol/L

Concept Question 5B
Titrations allow a chemist to determine the concentration of a substance, called the titrand, by carrying out a reaction with known quantities such as volume, moles, and concentration of the titrant used. In this experiment, a reaction between the acidic household cleaners and a standardized basic solution was used for the titration. In order to obtain standardization of the basic solution (NaOH), a specific volume of the substance was measured and diluted to an approximate concentration; the concentration of this resulting solution was then verified using titrations. Once the standardized NaOH solution was obtained, the household cleaner was first treated with a pH indicator (phenolphthalein) so that the equivalence point, the instant where exactly enough standard solution has been added to the titrand so that their molar concentrations are equal, could be seen. The equivalence point in the titrations conducted was equal to the end point, the instance at which the pH indicator changes color, which allowed the exact point of equivalence to be reached based on physical observation of the titrand. After the indicator had been added to the household cleaner being titrated, the titration was performed and the volume of NaOH required to reach the equivalence/end point was noted; the titration was then repeated twice more to ensure accuracy and precision. To determine the concentration of the household cleaner, first the volume of NaOH used to reach the equivalence point was multiplied by the concentration of that standard solution which yielded the number of moles of household cleaner used, as it and the NaOH reacted in a 1:1 ration. Finally, the moles of household cleaner in the solution was divided by the volume (in liters) of the household cleaner used in the titration, thus yielding the overall concencration for the household cleaner.

Cite This Document

Related Documents

  • Acid-Base Lab

    ...Title: Acid-Base Titrations AP Chemistry Laboratory #6 II.Purpose: The purpose of this experiment is to standardize a sodium hydroxide solution and use the standard solution to titrate an unknown solid acid. The equivalent mass of the solid acid will be determined from the volume of sodium hydroxide added at the equivalence point. The equilibri...

    Read More
  • Acid- Base Titration Lab

    ... Acid-Base Titration and Volumetric Analysis The purpose of this experiment is to determine the [NaOH] of a solution by titrating it with standard HCl solution, to neutralize a known mass of an unknown acid using the NaOH solution as a standard, to determine the moles of NaOH required to neutralize the unknown acid, and to calculate the m...

    Read More
  • lab oxalic acid

    ...Oxalic Acid Lab Aim: Use acid base titration to determine the number of water molecules in hydrated hydrochloric acid. Apparatus required: Oxalic acid solution 250 cm3 Weighing bottle Digital balance Beaker (250 cm3) Distilled Water Volumetric Flask 250cm3 Filter funnel Pipette Burette 50cm3 Retort Stand Beakers 100cm3 Stan...

    Read More
  • Lab Report Acid Base Titration

    ...EXPERIMENT 3: INTRODUCTION TO TITRATION – DETERMINATION OF THE MOLARITY AND CONCENTRATION OF SULPHURIC ACID BY TITRATION WITH A STANDARD SOLUTION OF SODIUM HYDROXIDE INTRODUCTION Reaction of acid and base is one of the most common reaction in chemistry. This reaction is also widely known as neutralization. In this experiment, we used titra...

    Read More
  • Lab Report Acid Base Titration

    ...Title: ACID BASE TITRATION. Objectives: 1. To determine the concentration of acid using titration. 2. Skills of titration techniques. Apparatus: 1. 250 volumetric flask 2. 10mL measuring cylinder 3. 25mL pipette 4. 50mL burette 5. 250mL beaker 6. 150mL conical flask 7. Retord stand 8. White tile ...

    Read More
  • Lab 5

    ...Exercise 5: Gymnosperms and Angiosperms ______________________________________________________________________________ OBJECTIVES: 1. Describe the distinguishing features of gymnosperms and angiosperms. 2. Understand the evolutionary significance of pollen and seeds. 3. Understand the function of a cone, a flower, and a seed. 4. Relate the ...

    Read More
  • Lab - Acid-Base Titration

    ...Lab Report # 11 By: Andrew Hoitt CHEM 105 Lab 11/29/2012 Lab # 11 – Acid - Base Titration Introduction: The purpose of this lab is to determine the molarity (M) of an unknown HCl solution. A NaOH solution will be made and its molarity calculated. A sample of the NaOH solution will be titrated against the u...

    Read More
  • Acid Lab

    ...Acids, Bases, and pH Lab In this lab the testing of whether or not a substance was an acid or a base occurred. Each substance was tested with the indicators red litmus paper, blue litmus paper, pH paper, phenolthalein, bromthymol blue, and phenol red. While the substances were tested the group noticed that the substances tested with the red and...

    Read More

Discover the Best Free Essays on StudyMode

Conquer writer's block once and for all.

High Quality Essays

Our library contains thousands of carefully selected free research papers and essays.

Popular Topics

No matter the topic you're researching, chances are we have it covered.