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Find out the percentage of citric acid present in lemon squash by using a neutralisation method of titration or volumetric analysis, and by using sodium hydroxide as the neutralising agent (it is an alkali).

Extracts from this document...

Introduction

RAJESH PATEL, 0175 CHEMISTRY COURSEWORK, PLANNING SKILL FINDING THE PARCENTAGE OF CITRIC ACID IN LEMON SQUASH (1) Aim The aim of my investigation is to find out the percentage of citric acid present in lemon squash by using a neutralisation method of titration or volumetric analysis, and by using sodium hydroxide as the neutralising agent (it is an alkali). Background Knowledge. What is titration? Titration is a procedure for analysing a solution by slowly adding another solution, in this way you are able to find out the minimum volume required to neutralise a solution, the analyte (constituent of interest). The solution added (known as the titrant) has a reagent, whose concentration known (also known as the standard solution, this is added to the analyte using a volumetric burette to measure precisely the volume let out. When enough titrant is added, the end point is achieved. An end point can be found by either using visually, by adding an indicator, or by using a apparatus to check some suitable property of the solution, such as the pH, that changes Fair test I am going to make this experiment a fair test by making sure the following don't differ in any way during the experiment. Volume of water in each beaker- this would give me a fair test if I were to keep it an equal volume of water in each beaker because then the results would be fair if I were to do more than one test. Temperature of water- this should start at the same rate because then the readings that are plotted on a graph would come out all wrong, i.e. if one started at 78 0C and the other at 45 0C, though both started at the same time their graphs would be incorrect. Volume of beakers- these beakers should be kept the same three sizes as this will increase or decrease the total surface area when doing the experiment. ...read more.

Middle

Note that sweating is also a form of excretion, since the sweat contains urea and also excess minerals. Sweating obviously has an effect on the body's water content (osmoregulation). Radiation Radiation involves the direct transfer of heat energy from the blood to the external environment. This is affected by the amount of blood which enters fine blood vessels nearest the surface: * Vasodilatation increases the loss of heat by radiation. Vasodilatation involves a widening of arterioles (narrow arteries) leading to the surface. * Vasoconstriction reduces the loss of heat by radiation. Vasoconstriction involves a narrowing of arterioles leading to the surface. Excessive heat loss from the body during cold conditions can lead to hypothermia. This is a serious risk for old people, who may be relatively inactive and who may have difficulty in affording sufficient food, clothing and fuel. Hypothermia is also a risk for those in cold water, since water rapidly conducts heat away from the body. Surface area/ volume ratio The relationship between surface area and the size and shape of organisms (or cells) is very important in CHEMISTRY. This is mainly because it is through the surfaces that substances are exchanged between the internal and external environment of an organism (or cell). Examples of this include gas exchange and temperature regulation. Surface area and volume (i.e. size) can be compared as a ratio. The surface area/ volume ratio (s.a./vol.) can be written: Surface area or s.a. Volume vol. RAJESH PATEL, 0175 CHEMISTRY COURSEWORK, PLANNING SKILL FINDING THE PERCENTAGE OF CITRIS ACID IN LEMON SQUASH (7) Although organisms (or cells) do not usually have a very regular, 'geometric' shape, surface area/ volume ratios can most easily be compared in cube-type shapes. (In the examples that follow, all the dimensions are of the same units.) Effect of the size on the s.a./vol. ratio Compare the cubes below. Cube 1 has a relatively large s.a. ...read more.

Conclusion

Firstly I will set up the apparatus as show on page 9. I will then collect one litre of boiling water from the kettle. ii) I will make final checks on the apparatus, and as soon as every one is in place I will pour the water into the beakers and begin the timer. Then will record the results on a table, shown later. iii) After that is done I will set out the results on a graph. iv) Then if it is possible I will repeat the investigation, but this time the smallest beaker will have a fur insulation Diagram- i) ii) RAJESH PATEL, 0175 CHEMISTRY COURSEWORK, PLANNING SKILL FINDING THE PERCENTAGE OF CITRIS ACID IN LEMON SQUASH (14) Results- i) Time, seconds Temperature loss for a beaker of size 500cm3 in 0C 0 30 60 90 120 150 180 210 240 270 300 330 360 390 420 450 480 510 540 570 600 RAJESH PATEL, 0175 CHEMISTRY COURSEWORK, PLANNING SKILL FINDING THE PERCENTAGE OF CITRIS ACID IN LEMON SQUASH (15 ii) Time, seconds Temperature loss for a beaker of size 200cm3 in 0C 0 30 60 90 120 150 180 210 240 270 300 330 360 390 420 450 480 510 540 570 600 RAJESH PATEL, 0175 CHEMISTRY COURSEWORK, PLANNING SKILL FINDING THE PERCENTAGE OF CITRIS ACID IN LEMON SQUASH (16) iii) Time, seconds Temperature loss for a beaker of size 30cm3 in 0C 0 30 60 90 120 150 180 210 240 270 300 330 360 390 420 450 480 510 540 570 600 Calculation to be done- I will do the following calculations- The rate at which temperature drops= Temperature 1- temperature 2 Time 1- time 2 To work out the ratio= Surface area: volume ratio Surface area of beaker: the volume of hot water it is holding And then simplify This will give the surface area: volume ratio RAJESH PATEL, 0175 CHEMISTRY COURSEWORK, PLANNING SKILL FINDING THE PERCENTAGE OF CITRIS ACID IN LEMON SQUASH (17) Conclusion- I think that my predicted results will be close to what I will actually get if I were to do the experiment. ...read more.

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