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20 Cards in this Set
- Front
- Back
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measurement
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a physical operation performed in comparison to a standard whose description must include a quantitative component
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What is meant by "Characterizing a solution?"
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describing a solution in terms of kinds of particle species present and amounts of species
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What's the difference between a counter ion and a conjugate ion?
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counter ion: DOES NOT have acid/base properties and is a spectator
conjugate: has acid/base properties |
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What is the most important property of a primary standard?
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It's #mmols can be determined through a simple drying and weight operation.
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When you measure "twenty-five" mL of water using a beaker, what value for volume do you write? Why?
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25 mL
The smallest marked divisions on the beaker are the tens place. Uncertainty occurs in the "5" value. |
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When you measure "twenty-five" mL of water using a graduated cylinder, what value for volume do you write? Why?
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25.0 mL
The smallest marked divisions on the graduated cylinder are the ones place. Uncertainty occurs in the tenths place. |
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When you measure "twenty-five" mL of water using a pipet, what value for volume do you write? Why?
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25.00 mL
The pipet makes a high quality measurement that is to the hundredths place. |
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What do we mean by "quality of a measurement?"
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Quality refers to the reproducibility or precision of a measurement.
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What is the distinction between "raw" and processed" data?
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raw data: directly generated measurements obtained in lab
processed data: involves mathematical manipulation of usually 2 or more raw measurments. Its quality cannot exceed that of the poorest associated raw measurement |
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What is the operating principle that governs how you write down a value for a piece of processed data?
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The quality of processed data cannot be better than the quality of the poorest associated raw measurement.
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A big deal was made about finding the range of the values that incorporated 95% of all values. What does identifying this range entitle you to state about the experimentally-determined density of water?
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A confidence interval gives an estimated range of values which is likely to include the true value. By looking at the 95% confidence interval we can state how certain we are about how uncertain we are about the value of water. Small ranges are preferred because they are more certain.
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How does the 95% range of mean density values compare to the 95% range for individual density values? What does this comparison suggest about how to make the most effective use of your measurement?
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The range of the mean density values was smaller than that of the individual values. This suggests that using means would be more effective and get you a value closer to the true value.
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What two properties does a primary standard have that allows it to be a primary standard?
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1. It's #mmol can be determined by a simple drying and weighing operation.
2. It is extremely pure, stable, and undergoes one invariable reaction with the other reactant of interest |
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Your first lab experiment is known as a standardization. What is it exactly, you are trying to achieve?
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We are trying to achieve the concentration of the titrant (OH-) to a high quality.
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What problem forces you to have to take do a standardization before working on the unknown KHP sample?
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We must know the concentration of the NaOH solution in order to determine the #mmoles of titrant need to reach the equivalence point. Because of a 1:1 relationship between the titrant (OH-) and the analyte (HP-) we will then be able to determine the %KHP.
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analyte
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The species being analyzed whose abundance is yet to be determined.
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titrant
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The species being added in a controlled fashion that specifically reacts with the analyte by means of a major reaction.
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primary standard
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A species whose #mmol can be determined to a high quality by a simple drying and weighing operation
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equivalence point
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The point where both the analyte and titrant are limiting reagents.
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titration
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A controlled major reaction between a titrant and an analyte in which the idea is to reach the equivalence point.
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