Findingout how much acid

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Finding out how much acid

There is in a solution

Aim

To find out the accurate concentration, of Sulphuric acid sample that is given. It is thought that the acid has a concentration between 0.05 and 0.015 mol dm-3. The solid anhydrous Sodium Carbonate that is provided has to be used to find the concentration of the acid.

Background Information

Sulphuric acid (24) is a strong mineral acid, which is soluble in water at all concentrations. It is the most widely used chemical. Principal uses include fertilizer manufacturing, ore processing, chemical synthesis, wastewater processing and oil refining.

    The hydration reaction of Sulphuric acid is highly exothermic. If water is added to the concentrated acid it can boil. Because the  of sulfuric acid is  favorable, sulphuric acid is an excellent dehydration agent, and is used to prepare many dried fruits.

     Sodium Carbonate (2) is a sodium salt of carboni acid. It is a white crystaline compound with a cooling alkaline taste and it is found in the ashes of many plants.

     It is used in the manufacture of glass, chemicals such as sodium  and sodium , the pulp and  industries, the manufacture of  and for the treatment of . It is also used as an  agent in many chemical industries.

The reaction between the compounds is as follows:

24(aq) + 2(aq) 24(aq) + 2O(l) + CO2(g)

Details

This investigation is simply a titration of Sodium Carbonate and Sulphuric Acid. The unknown concentration is always placed in the flask; therefore the Sulphuric Acid will be placed in the flask of this titration.

     As the sulphuric acid is thought to be between 0.05 and 0.015 mol dm-3, it will be sensible to use a 0.1 mol dm-3 of Sodium Carbonate, as it is half way between the predicted concentration of 0.05 and 0.015 mol dm-3.

    A standard solution has to be produced from the Sodium Carbonate, it is important to produce the standard solution as a 0.1 molar concentration.

    When producing a standard solution, the correct mass of powdered Sodium Carbonate has to be diluted with distilled water. Therefore it is important to calculate the mass of Sodium Carbonate that is going to be used to create the 0.1 molar concentration of the standard solution.

Quantity of Standard Solution

1dm3 of 2C3(aq) is 0.1 molar concentration

250cm3 is (0.1/4) = 0.025 moles

Mass = Mr × Moles

Mass = 106 × 0.025

Mass = 2.65 grams of 23

From the calculation above, 2.65 grams of 23 will be required to produce the standard solution.

Quantity of Sulphuric Acid

To gain a consistent result, the same amount of Sulphuric acid will be added to the beaker. To make the calculation more accurate and the result in standard figures I will add 10cm3 of Sulphuric acid. When coming onto the calculations it will be easier to calculate as this is a sensible figure.

 

Indicators

A chemical indicator is a compound which can change colour to indicate that the endpoint of a titration has been reached. The colour of an indicator changes because it is affected by the concentrations of ions in the solution.

Example

Strong acid - Weak base titration
HCl(aq) + NH
3(aq) -----> NH4Cl(aq)
NH
4Cl is the salt of a strong acid and a weak base, so a solution of NH4Cl will have a pH < 7 (NH4+ is a weak acid)
A suitable indicator would be
methyl orange (pH range 3.1 - 4.4) or methyl red (pH range 4.4 - 6.0)

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Sulphuric acid, is a strong acid and Sodium Carbonate is a weak base therefore it is now clear that a methyl orange indicator will be used to identify the neutralisation of the Sulphuric acid.

Apparatus

Methyl Orange Indicator

Sulphuric Acid (solution)

Sodium Carbonate (powdered)

Burette 50cm3

Retort stand, clamp and boss

White tile

Weighing boat

Graduated glass pipette 10cm3

Pipette Filler

250 cm3 Conical Flask  

Glass rod

Funnel   

Spatula

Two Decimal Place Balance

250 cm3 Standard Flask

Method

The first procedure of this investigation will be to make the standard solution of the 0.1 ...

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