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Müntz and of Warington on nitrification, and state the conditions necessary for the success of the process.

828. What are the constituents of gunpowder, and how is it made?

829. Mention the chief gaseous and solid products obtained by the explosion of gunpowder. How is the formation of each accounted for?

830. Taking the composition of gunpowder as 75 nitre, 10 sulphur, and 15 charcoal in 100 parts, and assuming that all the carbon is converted into carbon dioxide, and all the nitrogen obtained in the free state, find the volume of these gases at N.T.P. which should be evolved by the explosion of one gramme of the powder.

831. Able and Noble found that I gramme of gunpowder yielded by explosion in a closed vessel 280 c.c. of gases at N.T.P. What volume would they occupy at 2200° C. which is the temperature at the moment of exploding?

832. A piece of potassium when thrown on water yielded enough potash to neutralize exactly 79 c.c. of a solution of sulphuric acid containing 98 grammes H2SO4 per litre. Find the weight of the potassium.

833. How are the nitrite and carbonate of potassium obtained, and what are their properties?

834. How could you prepare potassium carbonate from the bicarbonate, and vice versâ?

835. What weights of potassium carbonate and of bicarbonate would be required to yield when treated with acid I litre of carbon dioxide at N.T.P.?

836. How are the potassium salts distinguished from those of ammonium and sodium?

837. Discuss the reasons for supposing that the salts of ammonia contain a hypothetical metal "ammonium." What is the so-called ammonium amalgam?

838. Compare the salts of potassium with those of ammonium, and point out their analogies.

839. What is meant by dissociation? Describe an experiment which proves the dissociation of ammonium chloride.

840. Describe the preparation of the carbonates and sulphides of ammonium.


841. Give a short account of Bunsen's discovery of rubidium and caesium, and give reasons for classing them with the alkali metals.

842. How is rubidium chloride obtained from lepidolite?

843 How is the metal rubidium prepared, and what are its properties?

844. Give the derivation of the names rubidium and caesium.

845. How may caesium and rubidium salts be separated?

846. What is the formula for caesium alum? can pure caesium sulphate be obtained from it?



847. How is silver extracted from its ores (a) in Mexico, (b) in Freiberg?

848. Describe the processes for the extraction of silver known as Ziervogel's, Augustin's, and Von Patera's. Explain the chemical reactions involved in each process.

849. What is the composition of English silver coin? How is the assay of an alloy of silver performed by the dry and wet methods?

850. How is silver extracted by the cupellation process? How is the "spitting" of silver in this process accounted for?

851. What occurs (a) when silver is heated to redness in air, (b) when steam is passed over melted silver, (c) when hydrochloric acid gas is passed over hot finely divided silver, (d) when chlorine is passed over heated silver?

852. How are the oxides, chloride and nitrate of silver prepared, and what are their properties?

853. Of what use are the silver salts in photography?


How is a negative taken, and how is a "print" obtained from it? State in each case how the result is rendered permanent.

854. Give a short historical sketch of the discovery of photography, and state the improvements due to Wedgwood, Niépce, Daguerre, Fox Talbot, Herschell, and Archer.

855. How is silver nitrate used in the analysis of chlorides, and how would you determine the amount of silver in a coin?

856. 2.971 grammes of a metallic chloride on precipitation with a silver salt yielded 4098 grammes silver chloride. Find the per cent. of chlorine in the salt, and its formula.

857. What happens when pure hydrogen is left in contact with solution of silver nitrate?

858. Russell found that 105.3 c.c. of hydrogen at N.T.P. precipitated 10089 gramme silver from a solution of silver nitrate. Calculate from this result the combining weight of silver.

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