• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Explain the need for primary and secondary standards in analysis

Extracts from this document...

Introduction

´╗┐Ardit Cenalia Unit 19 | M1 Explain the need for primary and secondary standards in analysis What is primary standard? A primary standard is a solution of which a concentrated is made from a primary standard. I.E. the substance available in a sufficiently pure from which requires no determination of concentration. A primary standard is one that can be determined to a high level of precision, and reliability. For instance, a typical acid-base titration can be done to determine the concentration of an unknown HCl solution. ...read more.

Middle

Potassium permanganate is an example of a secondary standard. It has to be standardised first, but then it can be used for quantitative analysis, A primary standard substance will not always be used in standardisation; this is because primary standard is a reagent which is very pure, representative of the number of moles the substance contains and easily weighed. For example sodium chloride is used as a primary standard for silver nitrate reaction. For example potassium hydrogen phthalate is used as a primary standard but because weak acid, wouldn?t be used to standardise a weak alkaline, like ammonia solution. ...read more.

Conclusion

Consequence of not having a standard substance. In a reaction between sulphate acid and sodium hydroxide, it is important to know the concentration of one of the reactants in order to determine the concentration of the unknown , base also on mole ration. NaOH+H2SO4ï Na2SO4+2H2O If the volume of sodium hydroxide is known = 25xm3, titre value of acid = 12.80cm3, concentration of sodium hydroxide = 0.5 mole. Number of mole of NaOH = (0.5X25)/1000 =0.0125 moles. Number of moles of H2SO4 = 0.0125/2 = 0.00625 Concentration of H2SO4 = (0.00625X1000)/12.80 = 0.48828125mol/dm3 It is important to know the standard substance by finding its concentration and the use this to find the know concentration. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Physical Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Physical Chemistry essays

  1. Investigating the Rate of the Reaction between Bromide and Bromate Ions in Acid Solution

    I will look at the potential for error in my investigation, and evaluate whether my method could have been improved. 4.1 Evaluation of Method Overall, I believe that the majority of the method that I used was successful. I believe I took the correct steps to ensure that my results were accurate.

  2. Methods of analysis and detection

    35 Chlorine - 37 3:1 M+4 Bromine - 79 Bromine - 81 1:1 In mass spectra, we will be also to be able to work out the number of carbon inside a compound. (Values will be given in the exam)

  1. Investigating how concentration affects rate of reaction

    Contact with eyes Pain. Redness. Permanent loss of vision. Severe deep burns. Face shield, or eye protection in combination with breathing protection. First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor. Ingestion Corrosive. Abdominal pain. Convulsions. Diarrhoea. Shock or collapse.

  2. Alkaloids are the most diverse group of secondary metabolites and over 5000 compounds are ...

    a number of compounds are also derived from: * Anthranilic acid * Nicotinic acid This classification however, fails to include the alkaloids derived from a polyketide or a terpenoid, with the incorporation of a nitrogen atom, ultimately from ammonia. Examples are Conine and batrachotoxin which are often known as 'pseudoalkaloids'.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work