This example illustrates the results from an acid-base titration experiment, where the concentration of hydrochloric acid (HCl) was determined using sodium hydroxide (NaOH) as the titrant.
In this experiment, a 25.00 mL sample of HCl was titrated with NaOH of known concentration (0.100 M). The endpoint was reached at 22.50 mL of NaOH added. The calculations for the concentration of HCl are as follows:
The final concentration of the hydrochloric acid solution was determined to be 0.090 M.
Notes: Ensure to conduct multiple trials for accuracy. Variations in titrant concentration may affect results.
This example reports the results of an experiment aimed at measuring the rate of reaction between sodium thiosulfate and hydrochloric acid, using a colorimetric method to determine the time taken for a precipitate to form.
In this experiment, 50 mL of sodium thiosulfate solution (0.1 M) was mixed with 5 mL of hydrochloric acid (1 M). The time taken for the solution to turn opaque (indicating the formation of sulfur) was recorded under varying temperatures:
The results indicate that the rate of reaction increases with temperature. The relationship can be summarized as follows:
| Temperature (°C) | Time to Precipitate (seconds) |
|---|---|
| 0 | 120 |
| 20 | 60 |
| 50 | 30 |
Notes: Conducting this experiment in controlled environments can help minimize variability. Consider using a stopwatch for precise timing.
This example presents the results from a quantitative analysis of copper in an unknown sample using gravimetric analysis. The sample was dissolved in nitric acid, and copper was precipitated as copper (II) phosphate.
The unknown sample weighed 1.000 g, and after performing the necessary reactions and filtration, the precipitate was dried and weighed:
The copper content in the original sample was determined to be approximately 22.5%.
Notes: Ensure that all reagents are of analytical grade to avoid impurities affecting the results. Repeating the experiment can validate findings.