Today's lab was all about putting our new knowledge of stoichiometry to the test. Given the equation NaHCO3(s) + HCl(aq) --> NaCl(aq) + CO2(g) + H2O(l), Zoe and I needed to figure out what the limiting reactant in the equation was, and discern how much salt (NaCl) would be left after the reaction occurred. We found this out using our experimental data and then checked our work using the wonderful conversion methods and moles of stoichiometry.
First, we added the sodium hydrogen carbonate (NaHCO3) to an evaporating dish.
Then we added the extremely corrosive chemical hydrochloric acid (HCl) to the mixture and watched it fizz. Next, we put in on the hot plate to aid in the chemical reaction. The hot plate caused the CO2 to bubble out and the H2O to evaporate, leaving behind the precipitate NaCl. Here's a clip of the bubbling and evaporation!
After the evaporation had finished, only one thing remained: the precipitate salt! I thought it was very cool that by mixing a bunch of chemicals, we ended up with something I could put on some french fries.
The limiting reactant was NaHCO3 because there was excess HCl, and the NaHCO3 was used up far more quickly. Here are my calculations.
The percent yield for this experiment was supposed to add up to 100%, but for some reason ours only added up to 77.93%. I believe this error is because of an accidental loss of material. At one point Zoe was accidentally spilled the substance onto the hot plate, so an amount of NaCl was lost out of the evaporating dish, so we were unable to measure that in the final product. There also might have been an error during the measuring portion due to the inaccurate balances.
No comments:
Post a Comment