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

Effect of temperature on pH of water samples

Extracts from this document...


Lab on effect of temperature on pH of water Lab type: DCP & CE/DCE. Theory: Water contains both hydrogen ions, H+, and hydroxide ions, OH?. The relative concentrations of these two ions determine the pH value.1 Water with a pH of 7 has equal concentrations of these two ions and is considered to be a neutral solution. If a solution is acidic, the concentration of H+ ions exceeds that of the OH? ions. In a basic solution, the concentration of OH? ions exceeds that of the H+ ions. On a pH scale of 0 to 14, a value of 0 is the most acidic, and 14 the most basic. A change from pH 7 to pH 8 in a lake or stream represents a ten-fold increase in the OH? ion concentration. Rainfall generally has a pH value Between 5 and 6.5. It is acidic because of dissolved carbon dioxide and air pollutants, such as sulfur dioxide or nitrogen oxides. If the rainwater flows over soil containing hard-water minerals, its pH usually increases. Bicarbonate ions, HCO3?, resulting from limestone deposits react with the water to produce OH? ions, according to the equation: HCO3? + H2O ? H2CO3 + OH? As a result, streams and lakes are often basic, with pH values between 7 and 8, sometimes as high as 8.5. The measure of the pH of a body of water is very important as an indication of water quality, because of the sensitivity of aquatic organisms to the pH of their environment. ...read more.


Testing Procedure 1. Plug the pH Sensor into Channel 1 of the Venire interface. 2. Turn the Vernier computer interface ON 3. You are now ready to collect pH data. 4. Remove the pH Sensor from the storage bottle. Rinse the tip of the sensor thoroughly with Distilled water. 5. Place the tip of the probe into the test tube. 6. Submerge the sensor tip to a depth of 3–4 cm. 7. Important: Leave the probe tip submerged for the 30 seconds that data is being collected. 8. Run the sample for 30 seconds, stop data collection and record the average pH on the Data & Calculations sheet. 9. Repeat step 4 to 8 for every sample at different temperatures starting from 29°c (room temp), 32°c, 35°c, 38°c,41°c,44°c respectively. Table 1: showing the pH of Tap water at different temperatures (uncertainty ± 0.01). TEMPERATURE Seconds/ Sample No. 29â° C 32â°C 35â°C 38â° C 41â°C 0 7.85 10.49 7.78 7.99 7.75 2 7.7 7.42 8.7 7.46 7.44 4 7.78 7.83 8.68 7.39 7.93 6 7.88 7.8 8.28 7.29 7.66 8 7.82 7.77 7.63 7.75 7.46 10 7.73 7.47 7.48 7.91 7.91 12 7.83 7.44 7.65 7.5 7.44 14 7.85 7.32 7.73 7.76 7.54 16 7.7 7.35 9.05 7.53 7.8 18 7.75 7.47 8.08 7.89 7.43 20 7.88 7.53 7.98 8.16 7.94 Mean 7.8 7.81 8.09 7.69 7.66 Std dev 0.07 0.91 0.49 0.28 0.21 Table 2: Showing pH of distilled water at different temperature (uncertainty ± 0.01). ...read more.


Temperature has very less and not much effect on pH of water. As temperature increases, the pH of water decreases. The most acidic was rain water at 32â°C with an average of 7.55 pH due to effect of acid rain. Evaluation-: While doing the experiment my all the data was perfect. There was no error, while doing the experiment. My result supported my hypothesis showed at the temperature. The temperature of each sample at each stage was not equally controlled due to contact with room temperature. There may be some external substances may have entered the sample and cause a variation in the pH level of the sample. The samples should have been covered to avoid any external substances in entering the sample. The pH value of each sample at different temperature was not the exact value as the pH value of the sample was counted only till 20 seconds. But getting more accurate value of pH the time (seconds) should have been more than 20 seconds like till 30 seconds or more. Conclusion-: My hypothesis was as the level of temperature increases the pH of water samples will decrease. My prediction seems to be supported my result that I collected. As the level of the temperature increase, the level of pH also increased is what I got. Graph 5. Showing mean value of pH at each different temperature mostly each sample at 35ºC was high as compared to others. As we can even see that 32C has the least mean in all. ...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. Investigate the rate of reaction of luminol in various factors. The objective was to ...

    This set of data provides a straight line from high concentration to low concentration. To find the order of reaction with respect to luminol, the graph has to be modified, where concentration of luminol now goes to the y-axis and the time of chemiluminescence goes to the x-axis.

  2. Percentage of Water In Popcorn

    The mass of the popped popcorn was the mass of the popped kernels added to the beaker, foil, and oil. The mass of unpopped popcorn in the denominator was the actual mass of the unpopped kernels massed alone. The beta kernels hold 11.1%, 11.3%, and 10.9% water for trials 1, 2, and 3 respectively.

  1. Free essay

    Vitamin C in Fruit Juices

    types of juices both contained fruits with very high ascorbic acid levels. This suprising result can be attributed to the type of container it was stored in and the time difference between doing the experiments; this will be discussed more in depth in the error discussion.

  2. A Comparison of Strong and Weak Acids and Bases

    1.00 2 HCl(aq) 1.00 3 CH3COOH(aq) 1.00 4 H2SO4(aq) 1.00 5 HCl(aq) 0.10 6 HCl(aq) 0.01 Balanced equations: a) 2HNO3(aq) + CaCO3(s) � CO2(g) + H2O(l) + Ca(NO3)2(aq) b) 2HCl(aq) + CaCO3(s) � CO2(g) + H2O(l) + Ca(Cl)2(aq) c) 2CH3COOH(aq) + CaCO3(s) � CO2(g) + H2O(l) + Ca (CH3COO)2 (aq)

  1. Strong and Weak Acids And Bases

    -9.97 | x 100 = 0.3 % error 10.00 CH3COOH and NaOH | 10.00 -11.27 | x 100 = 12.7 % error 10.00 Total % Error= 13.0% Percent Uncertainties HCI and NaOH 0.04 x 100 = 0.40 % uncertainty 9.97 0.04 x 100 = 0.35 % uncertainty 11.27 Total %

  2. Reactivity of Metals with Water and Acid

    The glowing splint was held just inside the mouth of the test tube. Observations were recorded and the waste was disposed of. Observations Part A: Reactivity of Metals in Water Element Calcium Magnesium Copper Physical properties Solid, silver, metallic, soft Long, thin, solid, smooth, malleable, silver, shiny Thin, solid, malleable,

  1. IB Chemistry Lab Design - compare the effect of temperature on the concentrations of ...

    As the temperature moves further away from room temperature (above or below) the concentration of Vitamin C/A in the solution should decrease due to denaturing or oxidation. The concentration of Vitamin C is calculated by doing an iodine titration. A starch solution is added to a standard Vitamin C solution which is the titrant.

  2. Biodiesel Investigation - How the concentration of Potassium Hydroxide solution would affect the yield ...

    Further Example Calculations (+ Observations included): Uncertainty of % yield of biodiesel Mass measured in grams % yield = 100 * (final mass ÷ initial mass) Uncertainty on Initial of substance: 33.119 ± 0.005 % unc. 0.005 ÷ 33.119 = 0.02% (1sf)

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