1What is conductor? give some examples and a reason for it.
substances that conduct electricity are called conductors. They have delocalised electrons. Eg: All metals and carbon ( graphite ), copper, aluminium
2What is insulator? give some examples and a reason for it
Substances that do not conduct electricity are called insulators. They do not have delocalised electrons. Eg: non-metals, Woods, plastics, rubber, ceramic
3State copper's uses and properties
electric wires. properties: good electrical insulators, ductile
4state aluminium uses and properties
overhead wire cables with steel core. properties: good electrical conductors, resists corrosion, low density
5state plastics uses and properties
insulation for wires. properties: poor electrical conductors, water proof
6state ceramics uses and properties
making pylons. propeeties: poor electrical conductor, high melting point
7What is electrolysis?
Electrolysis is the break down of molten or aqueous solution of ionic compound by a passage of electricity.
8state things needed for Electrolysis
Electrolyte, electrode, DC battery, bulb, beaker, wire
9Properties of inert electrode and give examples
do not take part in electrolysis ( unreactive ), conduct electricity, high melting point. Eg: graphite,platinum
10What is electrolyte
It is a molten or aqueous solution of ionic compound that conduct electricity by movement of ions.
11What is electrode?
It is a metal or graphite rod that conduct electricity by the movement of electrons.
12What is Cathode?
A negative electrode that attracts cations from the electrolyte.
13What is anode?
A positive electrode that attracts anions from the electrolyte.
14What is decomposition?
A breakdown of compound with different types of energy ( thermal, electrical, light, chemical )
15What reaction occurs at cathode?
Reduction because it gains electrons.
16What reaction occurs at anode??
Oxidation because it loses electrons.
17state observations of colors of metals ( most metals, copper, gold )
most metals--> silvery/ light grey liquid Copper--> pinkish brown. Gold--> yellow
18state the observations of colors of gases ( Chlorine, bromine, iodine, hydrogen and oxygen )
chlorine--> bubbles of green gas bromine--> bubbles of reddish brown iodine--> bubbles of purple gas hydrogen and oxygen--> bubbles of colorless gas
19Common name of aluminium ore
Bauxite or pure alumina
20Which solution is used to purify the pure alumina and why?
NaOH ( sodium oxide ) 1. to reduce melting point of Al2O3 ( 2)to decrease operating/ working temperature (3) to increase electrical conductivity of electrolyte
21state the temperature of the electrolyte: a mixture of alumina and molten cryolite
900°c
22Which will discharge between more reactive metal ions and hydrogen ion at the cathode? And why?
Hydrogen ions because less reactive ions are easier to discharge
23Which will discharge between less reactive metal ions and hydrogen ions at the cathode?
Less reactive metal ions ( Cu2+ , Ag+ , Au3+ )
24Which will discharge between Halide ions and hydroxide ion at the anode?
Halide ions
25Which will discharge between So4 2- or No3- and hydroxide ion at the anode?
hydroxide ion
26Which will discharge in a dilite solution?
Hydroxide ion
27State the electrolyte in a electrolysis of brine solution
brine solution or concentrated sodium chloride solution
28State the uses of hydrogen gas
1. As a fuel 2.making margarine from vegetable oils 3.making ammonia
29State the uses of Chlorine gas
1. purification of water 2. making bleach solution 3. making hydrochloric acid
30State the uses of sodium hydroxide solution
1. making soap 2. making bleach solution 3. purification of bauxite