The equation for the experiment is NaOH + CH3COOH CH3COONa + H2O
How to make it fair
I have to make this test fair otherwise there would be no point in doing the investigation. The most important thing, which may sound obvious, is that you clean the equipment with distilled water.
You must also assure that you use exactly the same amount of alkali in the beaker, otherwise it would become neutral at an unrealistic value as there would be different amount of alkali in the beaker.
I would also have to the average from the experiment. I decided as long as they were to 0.5cm cubed between each other I would use them.
Finally you would have to make sure you had the same amount of indicator, as it would be unfair as this can change the experiment.
Safety
The safety is the same that it always is in a chemistry lab as follows:
1. Safety glasses or goggles are to be worn at all times when working in the lab, observing chemical reactions, or preparing for a lab.
2. All accidents or spills must be reported immediately.
3. No food or drink is permitted in the laboratory area.
4. Nothing in the laboratory area should ever be tasted.
5. If smelling something in the lab is necessary, hold the material away from the face and gently waft the fumes toward the nose.
6. Laboratory areas should be kept clean and uncluttered.
7. Any chemical spills or burns on the body should be flushed with water immediately and the teacher notified.
8. Always to tuck in your tie and take your jacket off.
9. Never sit down when using chemicals.
- Never run around the lab and never leave bags in the aisle way.
The Making of Vinegar
All types of vinegar are made by the oxidation of alcohol. Any substance that is capable of fermentation or if the substance contains alcohol is possible to make vinegar from it. There are two different ways of making vinegar either a slow way or a quicker way.
The slow way is to use a weak alcohol from about 5 to 10%. You then leave the alcohol outside for about 4 weeks. The hotter the temperature the quicker the change. You then leave it to settle in a cool place until clear. The reason it turns into vinegar is because the ethanoic acid gets oxidised then turns into acetic acid. The more ethanoic acid the more acetic acid thus meaning it is stronger.
Hypothesis’
As it says above the making of vinegar is made by the oxidation of alcohol. As this is true I think that red wine would be the strongest of the vinegar’s, then white wine, then cider, then distilled and finally malt vinegar. Red wine as it is the most alcoholic will be the strongest vinegar. Also distilled will be the stronger than malt as it has no impurities.
Preliminary Results
For my preliminary results I had to choose what strength of alkali I should use and also which indicator I should use.
I tested all the vinegars with both strengths of alkali and with both indicators. The first thing that I noticed was that I t was impossible to use 0.4 moles of NaOH as it was too strong to be distilled by the vinegar’s. This meant I would have to use 0.1 moles of NaOH as it stays on the scale and comes up with a good reading.
Secondly I had to choose the indicator. Methyl orange turns from orange to peach. This was quite hard to measure exactly when this happened, as the colours are very similar. I then used phenolphthalein; this was a lot easier as it turned from bright pink to clear when it was neutral. I decided to use this, as it was far easier to measure when it was neutral.
Results
Analysis
The first thing is that I should have a table of results with just the averages and the amount of vinegar used:
This table shows the experiment a lot better, it is a lot clearer to see the averages and each experiment separately. This also shows that the strength has gone down with the less amount of alcohol. It goes up quite consistently with the wines and the cider then the vinegar. With the malt vinegar’s they are very close together.
Evaluation
The first thing that I should use the equation to find out what the Morality of the acid is: bMaVa = aMbVb
White Wine Vinegar:
1 x Ma x 9.3 = 1 x 0.1 x 10
Ma = 0.1075
x 10 = 1.075
You have to multiply by 10 as it is diluted!
Cider Vinegar:
1 x Ma x 10.20 = 1 x 0.1 x 10
Ma = 0.098
x 10 = 0.98
You have to multiply by 10 as it is diluted!
Red Wine Vinegar:
1 x Ma x 8.1 = 1 x 0.1 x 10
Ma = 0.123
x 10 = 1.23
You have to multiply by 10 as it is diluted!
Malt Vinegar:
1 x Ma x 11.5 = 1 x 0.1 x 10
Ma = 0.087
x 10 = 0.87
You have to multiply by 10 as it is diluted!
Diss. Malt Vinegar:
1 x Ma x 11.37 = 1 x 0.1 x 10
Ma = 0.088
x 10 = 0.88
You have to multiply by 10 as it is diluted!
This means that they go in the following order:
- Red wine Strongest
-
White wine
- Cider
- Diss. Malt
- Malt
This proves that my hypothesis was true and that the equation was right.
The experiment has worked very well and has been a success. I had 2 anomalies but I repeated these so they were fine. I then used these to work out the average. It shows that the more alcohol in a vinegar the stronger the vinegar is. If I did it again I would try and use a better way of measuring when it is neutralised!
