Chemical Effects of Electric Current Flashcards
Why is it dangerous to touch an electrical appliance with wet hands?
Water is a good conductor of electricity and it may have us if touched with wet hands.
Why is it preferable to classify materials as good conductors and poor conductors instead of classifying as conductors and insulators?
Under certain conditions most materials can conduct that is why it is preferable. For example air is a poor conductor of electricity but during lightning an electric current passes through air.
How can we test liquids whether they are a good conductor or poor conductor?
We can make a circuit with open ends which we will use to dip in liquids and test them. If the liquid between the two ends of the tester allows the electric current to pass the circuit becomes complete, the current flows in the circuit and the bulb glows. When the liquid does not allow the electric current pass the circuit of the tester is not complete and the bulb. In this way we can say that liquids are which conductors.
Give an example of heating effect of electric current.
Due to the heating effect of electric current, the filament of the bulb gets heated to a high temperature and it starts glowing.
Sometimes even if the liquid is conducting the bulb doesn’t glow. How can we make another tester to detect a week current?
We can use the magnetic effect of electric current in which we take a compass instead of bulb and if the liquid is conducting a weak current the compass needle will still deflect due to the magnetic field of electric current.
Why is distilled water not a good conductor of electricity? How can we make it conducting
The water that we get from sources such as taps, hand pumps, Wells and ponds is not pure. It may contain several salts dissolved in it. Small amounts of mineral salts are naturally present in it. This water is a good conductor of electricity, on the other hand distilled water is free of salts and a poor conductor.
We can make it conducting by dissolving salt, vinegar or lemon juice.
What are ions?
Ions are molecules that carry electricity. They are the components which make a liquid conducting. There are two types of ions : anions ( negetive ) and cations ( positive ). Example of ions are NACL ( salt ).
Name the liquids which conduct electricity?
Most liquids that conduct electricity are solutions of acids, bases and salts.
What are electrodes?
Electrodes are conductors of electricity which carry electricity into non metals. There are two types of electrodes : anode ( positive )and cathode ( negetive ).
What did William Nicholson do ?
In 1800, a British chemist, William Nicholson had shown that if electrodes were immersed in water, and current was passed, bubbles of oxygen were found on the positive terminal and hydrogen bubbles were found on the negative terminal.
What are the chemical effects caused seen in a conducting solution when passed electricity ? The reaction would depend on what?
The passage of an electric current through a conducting solution causes chemical reaction such as:
- bubbles of gas may be formed on electrodes
-deposits of metal may be seen on the electrodes
-changes of colour of solution may occur
The reaction would depend on what solution and electrodes are used.
What is electroplating? how is it done? Why is it done? Why is it done ?
The process of depositing a layer of any desired metal on another Material by means of electricity is called electroplating.
First we must take a solution with the component present for example copper sulphate and we must take two electrodes one with the desired metal and one with the metal we want to cover. The desired metal here is copper, we will put it on the positive terminal and the metal we want to cover ( carbon ) on the negetive terminal. When electricity will be passed the liquid taken ( copper sulphate) will divide itself into copper and sulphate from which the copper would get deposited upon the carbon ( negetive terminal) and the loss of copper from the solution would get recovered by the copper rod ( positive terminal). So it means that copper from one electrode is deposited on another electrode.
The layer of material deposited has some desired property, which the other electrode lacks.It can be done due to the following reasons :
- for making it look beautiful.
- for protecting it from corrosion.
- to make harmful objects not harmful.
Name some examples of objects which are usually electroplated and also tell why.
Chromium is electroplated upon many objects such as car parts, bath taps, kichen gas burners, bicycle handlebars, wheel rims, etc. It is done as chromium has a shiny appearance, It does not corrode and it also resists scratches but chromium is expensive may not be economical to make the whole object out of chromium. So, the object is made from a cheaper metal and only a coating of chromium over it is deposited.
Jewellery makers electroplate silver and gold on less expensive metals as these ornaments have the appearance of them but are made from much less expensive metals.
Tin cans used for storing food are made by electroplating tin onto iron, as tin is less reactive than iron. Thus, food does not come into contact with iron and is protected from getting spoilt.
Iron is used in bridges and automobiles provides strength however iron tends to corrode and rust, so, a coating of zinc is deposited on iron to protect it from corrosion and formation of rust.
What is an electrolyte and electrolysis?
A substance which conducts electricity in the liquid state or when dissolved in water and breaks up chemically in the process is called an electrolyte.
The process of breaking of an electrolyte chemically on passing an electric current through it is called electrolysis.
What are electrons and what is the opposite of it?
Electrons are the negatively charged particles which are light and contain negetive charge.
Protons are the positively charged particles which are light and contain positive charge.
