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I am attaching the science chemical effects notes and the math revision worksheet.
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I am attaching the science chemical effects notes and the math revision worksheet.
get the science notes below...
Maths notes will be uploaded in the mail
Chemical Effects Of
Electric Currents
Electrolyte: An aqueous solution of a chemical compound, which
conducts electric current and at the same time undergoes a chemical change is
called electrolyte.
Eg:Aqueous solutions of acids Hcl ,HNO3,H2SO4
aqueous solutions of alkalies as NaOH,KOH
Aqueous solution of soluble salts such as NaCl, CuSO4,NaNO3
Non Electrolyte:Eg: Petrol,Kerosene,diesel,vegetable oil,
Chloroform,alcohol,distilled water.
Electrolysis:When electricity is passed through certain solutions,they
decomposes into charged atoms.This process is called electrolysis.
Electrodes: The metal wires/plates/rods through which the
current enters or leaves an elecrolyte are called electrodes.The electrode connected to the negative terminal of
a cell/battery is called cathode.
The electrode connected to the positive terminal of a cell/battery is anode.
Electroplating:
It is the process of coating a metal object with a thin layer of another
metalby means of electrolysis.
In electroplating ,the object to be electroplated is made the cathode by
connecting it to the negative terminal of the battery. The metal which has to
be deposited is made the anode by connecting it to the positive terminal of a
battery. The electrolyte is an ionic compound of metal which has to be
deposited.
image for reference: http://www.ncert.nic.in/html/learning_basket/electricity/images/effects%20of%20current/electrolysis.gif
Uses of electrolysis:
· Electroplating is one of
the uses of electrolysis.
· Used to obtain pure metals
from the impure metals.
·
Used in the extraction of aluminium metal from its ore.
Q1.Is it safe for the electrician to carry out electrical
repairs outdoors during heavy downpour ? Explain.
Ans: It is never safe for the wireman to carryout electrical repairs
during heavy downpour.Because during heavy downpour there is a high risk of
electrocution.
Q2.A child staying in a coastal region tests the drinking
water and also the seawater with his tester. He finds that the compass needle
deflects more in the case of seawater. Can you explain the reason.
Ans: Seawater contains higher amounts of salts in compare to drinking
water hence sea water is a better conductor of heat. This is the reason that
the compass needle deflects more in case of sea water.
Q3.When the free ends of a tester are dipped into a solution, the
magnetic needle shows deflection. Can you explain the reason.
Ans: The deflection in the compass needle shows that current is flowing
through the circuit. The circuit is complete since free ends of the tester are
dipped in a solution. The solution is certainly a conducting solution. This is
the reason why the compass needle shows a deflection.
