Q16 of 27 Page 1

(a) Write the steps involved in the extraction of pure metals in the middle of the activity series from their carbonate ores.

(b) How is copper extracted from its sulphide ore? Explain the various steps supported by chemical equations. Draw labelled diagram for the electrolytic refining of copper.


a) Pure metals are extracted from their carbonate ores through the following steps:


1. Concentration of ore:


Gangue or matrix first needs to be removed from the ore keeping in mind the differences in physical and chemical properties of gangue and ore.


2. Calcination:


The carbonate ores must be heated strongly in absence of air to convert them into metal ores.


For example:


3. Reduction:


Next, reduction is carried out using a more reactive metal or carbon.


For example:


This happens because carbon has a greater binding affinity for oxygen than Zinc does.


Finally, the obtained metal is refined by electrolysis of their salt solutions.


b) Copper glance is the ore of copper sulphide. It is first roasted and then the remaining Cu2O is reduced using Cu2S in the tank.






This way, copper metal is extracted.



Electrolytic refining of copper: The electrolyte is a solution of acidified copper sulphate. The anode is impure copper, whereas, the cathode is a strip of pure copper. On passing electric current, pure copper is deposited on the cathode.


More from this chapter

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14

Students in a school listened to the news read in the morning assembly that the mountain of garbage in Delhi, suddenly exploded and various vehicles got buried under it. Several people were also injured and there was traffic jam all around. In the brain storming session the teacher also discussed this issue and asked the students to find out a solution to the problem of garbage. Finally they arrived at two main points– one is self management of the garbage we produce and the second is to generate less garbage at individual level.

(a) Suggest two measures to manage the garbage we produce.


(b) As an individual, what can we do to generate the least garbage? Give two points.


(c) List two values the teacher instilled in his students in this episode.


 15

What is a dam? Why do we seek to build large dams? While building large dams, which three main problems should particularly be addressed to maintain peace among local people? Mention them.

 17

(a) The modern periodic table has been evolved through the early attempts of Dobereiner, Newland and Mendeleev. List one advantage and one limitation of all the three attempts.

(b) Name the scientist who first of all showed that atomic number of an element is a more fundamental property than its atomic mass.


(c) State Modern periodic law.


 18

(a) Mention any two components of blood.

(b) Trace the movement of oxygenated blood in the body.


(c) Write the function of valves present in between atria and ventricles.


(d) Write one structural difference between the composition of artery and veins.


OR


(a) Define excretion.


(b) Name the basic filtration unit present in the kidney.


(c) and label the following organs of


excretory system which perform following functions :


(i) form urine.


(ii) is a long tube which collects urine from kidney.


(iii) store urine until it is passed out.