1a) A Standard Hydrogen Electrode (SHE) is an electrode that scientists use for reference on all half-cell potential reactions.
1b) metal have a strong tendency to lose electrons and act as good reducing agents. The reducing character increases from sodium to caesium. However lithium is the strongest reducing agent.
1ci)
1. Diamond is used in jewellery because, when cut by experts, it will sparkle and reflect light in an attractive way.
2. Diamond's hardness and high melting point make it useful for cutting tools, such as the diamond-tipped discs used to cut bricks and concrete.
1cii)
Because diamonds are very hard (ten on the Mohs scale) they are often used as an abrasive.
No1di)
Chemical change: this is a change which is irreversible and new substances are formed. They are mainly in form of chemical reaction.
(1dii)example of chemical change.
(I)rusting of iron
(II)reaction of acid and Base to form salt and water
(No1e)isotope: these are elements with the same atomic number but different mass number or atomic mass.
(No1f)
a weak acid is a substance which does not ionize or dissociate completely in solution. While a dilute acid is an acid with lower concentration, a dilute acid is formed when water is added to concentrated acid
(1g)
PH: this is the negative logarithm to the base ten(10) of hydrogen concentration
Ph= -log10^H+
(1h)
1. It causes formation of acid rain
2. It causes photochemical smog and ozone layer depletion
(1i)
Cl2 + Mgbr2 -> MgCl2 + Br2
(1fi)
By simple diffusion
(1fii)
Oxidation of the ethanol can be prevented by the removal of oxidizing agent such as Kmno4 or K2Cr2 or by the addition of lithium tetrahydrido aluminate(iii)
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NO2)
Functional group is a group of atoms responsible for the characteristic reactions of a particular compound.
no4a)The law of conservation of mass or principle of mass conservation states that for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as system mass cannot change quantity if it is not added or removed.
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4a ii)
1. The molecules themselves are small compared to the distances between the molecules.
2. Molecules are in constant random motion
3. There are frequent collisions between the molecules.
4b
i- producer gas
ii- water gas
iii-C(g) + H2O(g)----------= CO(g) +H20(g)
4ei
1....Production of hydrogen by electrolysis of water
2.... The metals like K, Mg, Al, etc., are obtained by electrolysis of Fused electrolytes...
3....In this method pure metal is deposited at cathode from a solution containing the metal ions
5a
chlorine
/ammonia
/hydrogen-
chloride gas/carbon(II) oxide/sulphur(IV)oxide/nitrogen(IV) oxide
5aibecause they are poisonous/
have offensive smell
/are dangerous to
health
5aii
1 Fused Calcium chloride is used in the manufacturing of plastics
2 Fused calcium chloride and the production of calcium salt. It is used in the production of concrete..
3 Fused Calcium chloride accelerates the curing (drying) speed of poured concrete.
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