• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Strong and Weak Acids And Bases

Extracts from this document...


Strong and Weak Acids and Bases Khan Salinder Purpose In this lab, a comparison will be made of the properties of strong and weak acids, as well as properties of dilutions of strong acids. Results & Analysis Experiment #1- Measurement of pH Values Calculations for Theoretical Values of pH Hydrochloric Acid 0.1M HCL HCl --> H+ + Cl- 0.1M HCl = 0.1M [H+] pH= -log[H+] pH= 1.0 0.01M HCl HCl --> H+ + Cl- 0.01M HCl = 0.01M [H+] pH= -log[H+] pH= 2.0 Ethanoic Acid 0.1M CH3COOH CH3COOH ? H+ + CH3COO- Ka =1.8x10-5 Ka = [H+][CH3COO] / CH3COOH] [ ] CH3COOH --> H+ + CH3COO- I C E 1.8x10-5 = [x][x] / [0.1] x2= 0.0000018 x = 0.0013 = [H+] pH= -log0.0013 pH= 2.9 0.01M CH3COOH CH3COOH ? H+ + CH3COO- Ka =1.8x10-5 Ka = [H+][CH3COO] / CH3COOH] [ ] CH3COOH --> H+ + CH3COO- I C E 1.8x10-5 = [x][x] / [0.01] x2= 0.00000017 x = 0.00041 = [H+] pH= -log0.00041 pH= 3.4 Sodium Hydroxide 0.1M NaOH NaOH --> Na+ + OH- 0.1M NaOH = 0.1M [OH-] pOH= -log[OH-] pOH=1 pH=14-1=13 pH= 13.0 0.01M NaOH NaOH --> Na+ + OH- 0.01M NaOH = 0.01M [OH-] pOH= -log[OH-] pOH=2 pH=14-2=12 pH= 12.0 0.001M NaOH NaOH --> Na+ + OH- 0.001M NaOH = 0.001M [OH-] pOH= -log[OH-] pOH=3 pH=14-3=11 pH= 11.0 Table 1- Experimental ph Values pH Value from pH paper � 0.5 Observation of ph Paper pH Value from pH meter � 0.05 0.1 M hydrochloric acid 1.0 Dark Red 1.10 0.01 M hydrochloric acid 2.0 Red 1.92 0.1 M ethanoic acid 3.0 Brown 2.75 0.01 M ethanoic acid 5.0 Light Orange 4.35 0.1M Sodium Hydroxide 12.0 Dark Green 13.76 0.01M Sodium Hydroxide 10.0 Green 11.63 0.001M ...read more.


This is exactly what should be expected, because with an increase in concentration of HCl, the concentration of hydrogen ions in the acid also increases. 0.1M Ethanoic acid had a pH of 3, so we can say that it was less acidic than the 0.1M hydrochloric acid. This is because ethanoic acid is a weaker acid while HCl is a strong acid with more hydrogen ions in its solution. The pH of an acid is defined as the 'power of hydrogen', so as the hydrogen ion concentration increases, the pH decreases. We can use this data to determine the exact value of the pH for HCl and ethanoic acid. From our results, we can determine that hydrochloric acid is a strong acid as it had a lower pH value as a dissolved substance, meaning there were many ions dissociated in the solution, resulting in more hydrogen ions. Ethanoic acid had a higher pH value, meaning there were less ions in the solution, less ions disassociated, fewer hydrogen ions, and therefore is a weaker acid. Our experimental and theoretical values were off, but these differences can be determined by human errors. The total % uncertainty for the pH paper was much greater than the total % error. Because the % uncertainty was larger than the % error, equipment uncertainties were more significant than systematic errors, while using the ph paper. Because the % error was larger than % uncertainty for ph meter, systematic errors were more significant than equipment errors. These % values make sense as the pH meter is obviously much more accurate than the pH paper. There were a few possible errors for this experiment. The errors of the pH paper were much more significant than human errors. ...read more.


Taking readings at eye level to avoid parallax errors would also improve measurement errors. Other human errors could have been adding too much of too little of a solution, which would effect the reactions. Conclusion In this lab we learned that: The properties of weak bases are: * Low conductivity * Less basic (lower pH values than strong bases) Weak bases will dissociate less, and therefore will have fewer ions to conduct heat/electricity. They will be less basic because there won't be as many OH- ions in the solution and pOH values will be high, resulting in low pH values. The properties of strong bases are: * Very high conductivity * Very basic (high pH values than weak bases) Strong bases will dissociate more, so there will be more OH- ions for conductivity, and to decrease the pOH values, which in turn will increase the pH values. This will make the solution very basic. The properties of weak acids are: * Low conductivity * Less acidic (higher pH values than strong acids) As with weak bases, weak acids will ionize less, so there will be fewer hydrogen ions for conductivity, and this will increase the pH values, making the solution less acidic. The properties of strong acids are: o High conductivity o Very acidic (low pH values than weak acids) Strong acids will ionize more, so the increase in hydrogen ions will improve conductivity and lower the pH value, making the solution more acidic. The properties of dilutions of strong acids are: o The more dilute solutions of strong acids will be weaker conductors and will have higher pH values. T o There will be fewer molecules to ionize, resulting in fewer hydrogen ions. As mentioned above, fewer hydrogen ions will result in the solution being a weaker conductor, and in being less acidic (higher pH value) ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related International Baccalaureate Chemistry essays

  1. A comparison of various proprieary antacids

    Moles of sodium hydroxide=0.010275 moles � 0.24% Initial moles of HCl= 0.0125 moles (� 0.24%) Moles of HCl that reacted with 20.55cm3 NaOH=0.010275 moles � 0.24% Moles of HCl that react with the antacid = 0.0125 moles (� 0.24%)-0.010275 moles (� 0.24%)

  2. Free essay

    pH titration curves Lab Report. How does the use of a strong acid with ...

    Furthermore, another table can be added to conclude the overall average of the three trials. Thus, this would enhance the accuracy of the results obtained from the pH titration experiment. Conclusion The data collected throughout the experiment will be displayed in a data table.

  1. Aim: Using an iodine clock reaction to find the order of hydrogen peroxide and ...

    Stop the time when the entire solution has turned black. 8. Repeat with different concentration of the liquids making up solution B. 9. Solutions of different concentrations can be created by increasing the amount of reactant that is being changed by two.

  2. Reactivity series for common metals experiment.

    � Iron: No texture/surface/color change (No Reaction) � Magnesium: Turns black on tis surface (Reaction) � Zinc: No texture/surface/color change (No Reaction) � Lead: No texture/surface/color change (No Reaction) I. Lead Nitrate (Pb (NO3)2 with: � Copper: No texture/surface/color change (No Reaction)

  1. Investigate the rate of reaction of luminol in various factors. The objective was to ...

    Unless the solution is very dilute, send the affected person to hospital and ensure that irrigation is continued during the journey. If spilt on skin or clothes: Brush off as much solid as possible. Remove contaminated clothing. Flood the affected area with large quantities of water.

  2. Aim: To study and investigate the effect of temperature on the rate of ...

    Swirling the contents of the conical flask leads to faster cooling. As a result the experiment is not performed at a constant temperature possibly leading to inaccurate results. Precautions Precautions must be taken so as to avoid the occurrence of errors: 1.

  1. Investigation of reversible reactions at equilibrium - CuCl2 (s) was added to HCl , ...

    + 2H+ (aq) â Cr2O72- (aq) + H2O (l) When sulphuric acid is added to the aqueous potassium chromate there is an increase in the concentration of H+ ions. According to Le Chatelier’s principle when a system under equilibrium is stressed the system moves in order to oppose the stress.

  2. Determining Ka by the half-titration of a weak acid

    As I calculated both I can calculate the % error of both comparing it with the actual value, -4.76.[1] % error of method 1= = 100 ±5% % error of method 2= = 100 ±0.84% The data I have concluded and summarized above is backed up by the data produced in the experiment and trends seen.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work