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CHEM1100 Experiment 4 Lab Report
Chemistry 1 (CHEM1100)
University of Queensland
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CHEM1100 Experiment 4 Laboratory Report THE HEAT IS ON! Name Partner P Group and team Student Number Demonstrator Date lab completed This report template is to be completed and submitted through Blackboard within two weeks after completing your experiment. Please use Arial, Font size 11. The text boxes are fixed, please do not change these. Do not copy and paste text as an image into the text box. Introduction: State the purpose of the experiment and background. The purpose of this experiment was to find the change in enthalpy of the decomposition of hydrogen peroxide (H2O2). In this case, heat of decomposition is the result of H2O2 dissociating into two simpler compounds, water and oxygen gas. This experiment is relatively simple and would be done using a coffee cup calorimeter. Firstly, the calorimeter would be calibrated using HCL and NaOH. Then, some H2O2 would be placed into the calorimeter and it would automatically start dissociating in room temperature as H2O2 is an unstable compound. However, this process is very slow, hence a catalyst will be used to speed up the reaction. Catalysts are special, in that they are able to speed up a reaction without altering the change in enthalpy, thus accurate values can be calculated. Experimental Section: Include a short general description of the experimental procedure for the calibration and hydrogen peroxide decomposition reactions. Remember to use the past tense, passive voice. Firstly, a coffee cup calorimeter was constructed using two Styrofoam cups and a Styrofoam lid (upside-down Styrofoam cup). A temperature probe was attached to the lid so it could record the internal temperature. A 100-ml beaker was placed inside the calorimeter and the entire contraption was placed on top of a magnetic stirrer. For the calibration step, 25 ml of HCL was measured and added to the beaker; and, 25 ml of NaOH solution was measured and kept ready. Then, a magnetic bar was placed inside and the stirrer was turned on. The lid, along with the temperature probe was closed into the calorimeter making sure the probe was not incontact with the base or the sides. The Lab Quest was turned on and the temperature was allowed to settle for a further six seconds. Immediately, the lid was removed and the prepared 25 ml on NaOH was added to the beaker, then the lid was closed. The temperature was recorded for 220 s and the data were later analysed. For decomposition, a similar experiment path was followed; however, the first reagent changed to 40 ml 6% Hydrogen Peroxide and the second to 10 ml of FeCl3. The temperature change was again collected for 220 s and the data were later analysed. Results Section: Using your experimental data, calculate the enthalpy of the catalytic decomposition of hydrogen peroxide. You will first need to calculate the effect of the calorimeter and number of moles hydrogen peroxide used, from your data. Remember to include appropriate working and units. Use the hints in the Lab Manual to help you. 𝐽 Ccalorimeter (J) 107 𝐾 Number of moles hydrogen peroxide added 0 Calculation 1 Mass of solution (g) 2 Csoltn (J K-1) 3 tH(J) 4 rH(J) 5 Moles H2O2 (from above) 6 H H2O2 (kJ mol-1) Value 1 g × 50 mL = 55 mL 2 𝑔 × 55 (145 J = 145 gK J J + 107 ) × 32 K = 8384 J K K −∆𝑡 𝐻 = ∆𝑟 𝐻 ∆𝑟 𝐻 = −8384 𝐽 𝑛 = 0 8384 𝐽 − 1000 𝐾𝐽 ∆𝐻2 𝑂2 = ( ) = −118 0 𝑚𝑜𝑙 𝑚𝑜𝑙
CHEM1100 Experiment 4 Lab Report
Course: Chemistry 1 (CHEM1100)
University: University of Queensland
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