Record the mass of an empty weighing bottle. weigh accuratelyg (your suggested mass) of fa 4 in this weighing bottle. place a polystyrene cup in a second polystyrene cup. place both cups in a 250 cm3 beaker to prevent them from tipping over. measure suggested volume) of fa 3 cylinder 2. cm3 (your into the first polystyrene cup using a measuring 3. record the temperature of fa 3 every 30 seconds for 2.5 minutes. 4. at exactly 3.0 minutes, carefully add fa 4 into the cup to avoid too much frothing that might cause the mixture to overflow. place the lid onto the cup and insert the thermometer mix the solid with the solution. continue to record the temperature every 30 seconds from 3.5 minutes to 10.0 minutes. through the lid. stir the mixture thoroughly with the thermometer to 5. reweigh the weighing bottle and any remaining solid. record all measurements of mass and temperatures clearly in an appropriate format on the next page.
fa 2 is 1.00 mol dm-3 aqueous sodium carbonate, na2co3(aq) fa 3 is 2.00 mol dm-3 aqueous hydrochloric acid, hcl(aq) fa 4 is solid sodium carbonate, na2co3(s) in experiments 1 and 2, you will determine the enthalpy changes for the following reactions: ah1 (exdlemnic) na2co3(aq) + 2hc/(aq) → 2nac/(aq) + h20() + co2(g) nac03(s) + 2hc/((aq) + h2o() + co2(g) use the following information in your calculations: assume 4.18 j is required to raise the temperature of 1.0 g of each solution by 1.0 k, and that the density of each solution is 1.00 g cm-3. relative atomic mass: na, 23.0; c, 12.0; o, 16.0; h, 1.0; cl, 35.5
na2cos(s)+ 2hc/(aq) 2nac/(aq) + h2o() co2(g) in this experiment, you will choose suitable quantities of fa 3 and fa 4 to mix together. in a preliminary investigation, adding 2.12 g of na2cos(s) to 100 cm3 of hcl(aa) resulted in a temperature rise of 1.6 °c, the percentage error for δτ is calculated as 0.1+0.1 1.6 11tal x 100% 12.5%. it is recommended that the percentage error for δt should not exceed 5% for the results to be reliable. in addition, hci(aq) should be used in excess because the dissolving of any excess na2co3(s) causes a heat change as well. the total volume of mixture should be sufficient to cover the bulb of the thermometer but preferably not exceed 2% of a cup to avoid spillage. suggest a suitable volume of fa 3 and a suitable mass of fa 4 to use in your experiment. the volume of fa 3 should not exceed 60 cm3. justify your choice with relevant calculations on the next page.