A titration involves reacting two solutions - one with a known concentration and the other with an unknown concentration. The goal of the lab is to calculate the concentration of acetic acid in vinegar, so that is the solution with the unknown concentration. Therefore, there must be a way to find the concentration of the base solution so that it can be known. A separate procedure can be used to do this. The process is called standardization and is formally defined as the process by which the concentration of a standard solution is determined by titration against a primary standard. The primary standard used in standardizing sodium hydroxide is potassium hydrogen phthalate, otherwise known as KHP.
1. KHP is a solid. What tool in the lab can you use to be sure within 4 significant figures of the number of moles of acid in your reaction?
2. You will need to make a more dilute solution of sodium hydroxide than the 6 M sodium hydroxide that you'll find in the hood to react with KHP. It is recommended that you make a 0.2 M solution. How many significant figures are represented by a 6 M solution of sodium hydroxide?
3. How will you make a 0.2 M solution of sodium hydroxide from a 6 M solution of sodium hydroxide? Provide detail.
4. Do you have more significant figures to describe the number of moles of KHP? Or the number of moles of sodium hydroxide?
Titration related questons involving dilution and significant figures are solved.
Experiment Observations Results and Explanations
A. Reigniting a Candle
B. Water Suck Up
C. Extinguishing a Candle with Aluminum Foil
D. Candle Condensation
E. Extinguishing a Candle with Carbon Dioxide
1. Why would the candle reignite with a match held away from the wick?
2. a) Explain how the candle would extinguish with aluminum foil and carbon dioxide.
b) Suggest and explain another method of extinguishing a candle not already used in Part A.
c) Write out the balanced chemical equation for the reaction that produced carbon dioxide.
3. What does the formation of water on the aluminum ice sack suggest about the chemistry of a burning candle?
4. a) Suggest a reason why the water is sucked up into the glass jar.
b) A candle flame will use up oxygen as it burns. However, the consumption of oxygen alone does not explain the observed volume change. What other factor (s) need to be considered?
5. Explain the difference in the shapes of a normal candle flame and a nearly identical candle in micro gravity.