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The haber process

World food production depends on nitrogen fertilisers. These fertilisers are made from ammonia. which is made by the haber process.

The word equation for the haber process is;


the balanced symbol equation for the haber process is;

The optimum conditions for the haber process are to;

-use an iron catalyst;- raise the temperature to about 450degrees C; - use high pressure ( about 200 atmospheres);- recycle any unreacted nitrogen and hydrogen

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the haber process

The conditions used in the haber process are designed to make th process efficient as possible

-the iron catalyst increases the reaction rate but not the percentage yield.

-High pressure increases the percentage yield of ammonia

- a high temperature increases the reaction rate

- the optimum temperature is around 450degrees C. Although the percentage yield is not very high, the rate is fairly quick.

This is the best compramise or 'best of bad balance'

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What effects the cost of chemical manufacture?

Costs increase when the pressure is raised (increasing the plant costs) and the temperature is raised (increasing the energy costs).

costs decrease when catalysts are used, unreacted starting materials are recycled and automation is used (reducing wage bills).

These economin=c considerations determine the conditions used to manufacture a chemical.

-both the reaction rate and the percentage yield must be high enough to give a sufficient daily yield of product.

-a low percentage yield can be accepted if the reaction can be repeated many times with recycled starting materials.

-optimum conditions give the lowest cost, rather than the fattest rate or highest yields.

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acids, bases, alkalis and neutralisation

Metal oxides and metal hydroxides are bases. A few bases are soluble in water, and are called alkelis, e.g sodium hydroxide and calcium hyrdroxide.

Neautralisation takes place when an acid and a base react to make salt and water. The word equation for neautralisation is; acid+base=salt+water

some indicators show a sudden colour change at one pH value. Universal indicator shows a gradual range of colour changes, as it contains a mixture of different indicators.

In solution, all acids contain H+ irons (hydrogen ions). The pH of an acid is determined by the concentration of H+ ions - the higher the concentration the lower the pH. Neutralisation leaves no free H+ ions.

Alkalis contain OH- ions (hydroxide ions)

Neutalisation involves this reaction;

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Acids react with bases and metal carbonates to form salts. The word equations for making salt are; acid+base=salt+water OR acid+metal carbonate=salt+water+carbon dioxide

Salt names have two parts- the second part of the name shows which acid it has been made from for example; common acid is sulfuric and second part of the salt name would be sulfate.

Some common chemical equations for the neutralisation of acids by a base or metal carbonate can be constructed using;- sulfuric acid,nitric acid, hyrdrochloric acide; - ammonia, potassium hydroxide, sodium hydroxide and copper oxide; - sodium carbonate and calcium carbonate

The word equation for the reaction between hyrdrochloric acid and copper carbonate is; hydrochloric acid+copper carbonate=copper chloride+water+carbon dioxide

The symbol equation for the reaction is;

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