Volumetric Analysis: Acid-Base Concentrations

A titration is used to determine the concentration of a solution by adding a measured volume of another solution until the reaction is complete.

A volumetric flask is designed to contain a definite volume of solution and has an engraved graduation mark on its neck.

Rinsing a graduated cylinder with deionised water removes contaminants and ensures accurate measurement of liquids.

<p>A pipette is filled by drawing the solution into it by suction, going above the etched graduation mark and then allowing it to settle.</p> Signup and view all the answers

<p>After filling the volumetric flask to the mark, it should be inverted about 20 times to ensure a well-mixed, homogenous solution.</p> Signup and view all the answers

<p>14.625 grams NaCl per litre</p> Signup and view all the answers

<p>0.092 M NaOH solution</p> Signup and view all the answers

<p>0.014 moles NaOH</p> Signup and view all the answers

<p>0.6 g magnesium</p> Signup and view all the answers

<p>No. of moles = (Volume_dil x M_dil) / 1000.</p> Signup and view all the answers

<p>125 cm³ of 12 M HCl solution</p> Signup and view all the answers

<p>40 g/mol</p> Signup and view all the answers

<p>One mole of H₂SO₄ reacts with one mole of Mg.</p> Signup and view all the answers

<p>To remove any contaminants and ensure that the pipette is clean.</p> Signup and view all the answers

<p>To remove any drop that may be adhering to the tip, ensuring an accurate measurement.</p> Signup and view all the answers

<p>The meniscus represents the true level of the liquid and should be at eye level to ensure accuracy.</p> Signup and view all the answers

<p>Rinse the burette with deionised water, then with the hydrochloric acid solution before filling it above the zero mark.</p> Signup and view all the answers

<p>The tap at the base should be opened to allow the liquid to flow until the air bubble is cleared.</p> Signup and view all the answers

<p>Rinsing with the solution could lead to dilution and inaccurate results.</p> Signup and view all the answers

<p>Methyl orange indicator helps visualize the endpoint of the titration by changing color.</p> Signup and view all the answers

<p>The conical flask is used for mixing the reagents and allows for swirling without spillage.</p> Signup and view all the answers

<p>A solution is a completely perfect mixture of a solute and a solvent, where particles of the solute are uniformly distributed throughout the solvent.</p> Signup and view all the answers

<p>Weight per weight (w/w) is expressed as grams of solute per 100 grams of solution.</p> Signup and view all the answers

<p>To ensure that the concentration of acetic acid is within a measurable range for accurate titration results.</p> Signup and view all the answers

<p>A 0.85% w/v solution of NaCl indicates that there are 0.85 grams of NaCl per 100 cm^3 of solution.</p> Signup and view all the answers

<p>It changes from pink to colourless.</p> Signup and view all the answers

<p>Parts per million (ppm) is used for very dilute solutions and indicates 1 mg of solute per litre of solution.</p> Signup and view all the answers

<p>Molarity is the number of moles of solute per litre of solution.</p> Signup and view all the answers

<p>To prevent contamination that could affect the accuracy of the titration results.</p> Signup and view all the answers

<p>By using the volume and concentration of sodium hydroxide used to reach the endpoint in the titration.</p> Signup and view all the answers

<p>To convert, multiply the molarity (0.25 M) by the molar mass of NaCl (approximately 58.44 g/mol).</p> Signup and view all the answers

<p>Invert the flask several times to ensure a homogeneous solution.</p> Signup and view all the answers

<p>A 10% v/v ethanol solution means it contains 10 cm^3 of ethanol per 100 cm^3 of solution.</p> Signup and view all the answers

<p>The formula is: mass = (concentration w/v) x (volume in cm^3)/100.</p> Signup and view all the answers

<p>It refers to the water molecules that are chemically bound within the crystalline structure of the compound.</p> Signup and view all the answers

<p>It ensures the accuracy and reliability of the titration results.</p> Signup and view all the answers

<p>The indicator changes from yellow to red/pink.</p> Signup and view all the answers

<p>A standardised solution is one whose concentration is exactly known and used as a reference for titration.</p> Signup and view all the answers

<p>Dissolve the weighed sample in deionised water, stir until fully dissolved, then transfer to a volumetric flask, rinsing the beaker and bring the solution to the mark.</p> Signup and view all the answers

<p>Add the titrant drop by drop to avoid overshooting the endpoint, ensuring accurate determination of titration end point.</p> Signup and view all the answers

<p>Methyl orange is a suitable indicator, which changes from yellow to pink at the endpoint.</p> Signup and view all the answers

<p>The concentration of sodium carbonate in the original solution is 0.0432 moles/L.</p> Signup and view all the answers

<p>The concentration of sodium carbonate is 4.58 g/L.</p> Signup and view all the answers

<p>Calculate the mass of water in the hydrated compound, then divide by the total mass of the hydrate and multiply by 100 for the percentage; x is determined based on the molar ratio between sodium carbonate and water.</p> Signup and view all the answers

<p>Thorough dissolution ensures that all solute particles are in solution for accurate and consistent titration results.</p> Signup and view all the answers