Lol so I know that this isn't really a question for girlsaskguys, but yahoo answers wasn't working for me. Anyway, I have a chemistry lab and I don't understand the Pre-Lab questions at all, help?
The approximate concentration of a hydrochloric acid solution is 0.5 M. The exact concentration of this solution is to be determined by titration with 0.215 M sodium hydroxide solution.
1. A 10.00-mL sample of the HCl solution was transferred by pipet to an Erlenmeyere flask and then diluted by adding about 40 mL of distilled water. What is the approximate H3O+ concentration and pH of the solution in the flask before the titration begins?
2. Phenolphthalein indicator was added, and the solution in the flask was titrated with 0.215 M NaOH until the indicator just turned pink (pH = 8-9). The exact volume of NaOH required was 22.75 mL. use the following equation to calculate the concentration of HCl in the original 10.00-mL sample.
Mb x Vb = nMa x Va
Mb = molarity of standard base solution, Ma = unknown molarity of acid solution, Vb = volume of base added, Va = initial volume of acid solution, and = mole ratio (number of moles that react with one mole of acid)
3. One student accidentally "overshot" the endpoint and added 23.90 mL of 0.215 M NaOH. Is the calculated concentration of HCl likely to be too high or too low as a result of this error?
The approximate concentration of a hydrochloric acid solution is 0.5 M. The exact concentration of this solution is to be determined by titration with 0.215 M sodium hydroxide solution.
1. A 10.00-mL sample of the HCl solution was transferred by pipet to an Erlenmeyere flask and then diluted by adding about 40 mL of distilled water. What is the approximate H3O+ concentration and pH of the solution in the flask before the titration begins?
2. Phenolphthalein indicator was added, and the solution in the flask was titrated with 0.215 M NaOH until the indicator just turned pink (pH = 8-9). The exact volume of NaOH required was 22.75 mL. use the following equation to calculate the concentration of HCl in the original 10.00-mL sample.
Mb x Vb = nMa x Va
Mb = molarity of standard base solution, Ma = unknown molarity of acid solution, Vb = volume of base added, Va = initial volume of acid solution, and = mole ratio (number of moles that react with one mole of acid)
3. One student accidentally "overshot" the endpoint and added 23.90 mL of 0.215 M NaOH. Is the calculated concentration of HCl likely to be too high or too low as a result of this error?
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