Both diamond and graphite have giant atomic structures. Explain why diamond is hard while graphite is soft.

Answer:

- In diamond each carbon atom is covalently bonded to four other carbon atoms
in a rigid giant atomic structure while in graphite each carbon atom is covalently
bounded to three other carbon atoms in layers. The layers are held together by weak
Vander Waal

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in an experiment, soap solution was added to three separate samples of water. The table below shows the volumes of the soap solutions required to form lather with #1000cm^3# of each sample of water before and after boiling. a) Which water sample is likely to be soft? Explain. (b) Name the cause of change in the volume of soap solution used in sample III (Answered)
in an experiment, soap solution was added to three separate samples of water. The table below shows the volumes of the soap solutions required to form lather with #1000cm^3# of each sample of water before and after boiling. a) Which water sample is likely to be soft? Explain. (b) Name the cause of change in the volume of soap solution used in sample III .
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A sample of water drawn from a river passing through an agricultural district was divided into two portions. The first portion gave a white precipitate when acidified barium chloride was added. The second portion when warmed with aqueous sodium hydroxide gave a colourless gas which turned a moist red litmus paper blue. (a) Identify the ions present in the river water. (b) Suggest the possible (Answered)
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The column below was used to soften hard water (i) Explain how hard water was soften as it passed through the column. (ii) After sometime the material in the column is not able to soften hard water. How can the material be reactivated? (b) Give one advantage of using hard water for domestic purposes. (Answered)
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The following tests were carried out on three separate portions of a colourless solution R. (a) From the information in test (i), name a cation which is not present in solution (b) Identify a cation, which is likely to be present in solution S (c) Write an ionic equation for the reaction which takes place in test(ii) (Answered)
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