As the NaOH reacts with water from its surroundings, the moles of NaOH would decrease and that would also bring the molarity down. For our standard acid test we used KHP which also helped to eliminate errors. KHP is a weak acid and therefore it has less reactivity. Our KHP was in a solid and dry powder form which allowed us to mass it out using the scale. Because it was a solid, this got rid of the error of evaporation to occur and led us to be more accurate with out results. We also used a compound with a high molecular mass. The KHP had a molecular mass of 204.23 g/mol. If the compound had a low molecular mass, there would be a significant change if we were off one or two grams which would be a big error. The phenolphthalein that we added helped us decide when we added enough base to neutralize the excess H+’s in the HCl solution. We saw the color change occur when 22.9 ml were added to the solution. If we had added any more of the NaOH we would have went greatly past the endpoint which would be an unsuccessful titration and the hue would become a very dark pink. Even though the phenolphthalein is a useful color indicator, if we added too little of it we might have not been able to tell at the exact moment when the color change took
As the NaOH reacts with water from its surroundings, the moles of NaOH would decrease and that would also bring the molarity down. For our standard acid test we used KHP which also helped to eliminate errors. KHP is a weak acid and therefore it has less reactivity. Our KHP was in a solid and dry powder form which allowed us to mass it out using the scale. Because it was a solid, this got rid of the error of evaporation to occur and led us to be more accurate with out results. We also used a compound with a high molecular mass. The KHP had a molecular mass of 204.23 g/mol. If the compound had a low molecular mass, there would be a significant change if we were off one or two grams which would be a big error. The phenolphthalein that we added helped us decide when we added enough base to neutralize the excess H+’s in the HCl solution. We saw the color change occur when 22.9 ml were added to the solution. If we had added any more of the NaOH we would have went greatly past the endpoint which would be an unsuccessful titration and the hue would become a very dark pink. Even though the phenolphthalein is a useful color indicator, if we added too little of it we might have not been able to tell at the exact moment when the color change took