Chemistry Obj
1-10: ABDCBCABAC
11-20:DACBBACCAA
21-30: CBCDCDAAAB
31-40: AABACBABAA
41-50: DBBDCBCCDB
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THEORY ANSWERS
NO 1
1ai)
Fermentation is the process in which a
substance breaks down into a simpler
substance. Microorganisms like yeast and
bacteria usually play a role in
thefermentation process, creating beer,
wine, bread, kimchi, yogurt and other
foods. Fermentation comes from the Latin
word fermentare, meaning “to leaven.
(1aii)
Zymase
1bi). daltons law of partial pressure tates
in a mixture of non-reacting gases, the
total pressureexerted is equal to the sum of
thepartial pressures of the individual gases.
(1b)
-The strength of an acid
-The PH of the solution
(1c)
Fe+H2SO4->FESO4 + H2
H2SO4=10cm^3
Concentration=1mol/dm^3
Amount=Vol * Concentration
=10/100*1
=0.01mol
1mol=56g
0.01mol=56*0.01
=0.56g
Mass of unreacted=5-0.056
=4.44g
1di)
copper(ii) tetraoxsulphate(iv)
1dii). dyes
1e) A catalyst increases the rate of reaction
by lowering the activation energy of the
reaction
1fi) CH3COOH + NH3 → CH3COONH2 +
H2(g)
fii)
Ethanamide
(1g)
(a) It doesn't corrode easily.
(b) it doesn't react with contain inside.
(c) It can stand for a long period of time.
(1h)
(a) Sweet production industries
(b) perfume industries.
(1i)
(a) Evaporation
(b)seedling
(1j)
(a) it increases the volume water in ocean
and seas.
(b) It causes increase in rainfall and also
corrode painted surfaces
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Section B
NO 2
2a. The collision theory states that when
suitable particles of the reactant hit each
other, only a certain percentage of the
collisions cause any noticeable or
significant chemical change; these
successful changes are called successful
collisions. The successful collisions must
have enough energy, also known as
activation energy , at the moment of impact
to break the preexisting bonds and form all
new bonds. This results in the products of
the reaction. Increasing the concentration
of the reactant particles or raising the
temperature, thus bringing about more
collisions and therefore many more
successful collisions, increases the rate of
reaction.
(2aii)
When the rate of collision increases, the
rate at which molecules collide with each
other will also increase thereby making the
kinetic energy of the molecules to also
increase. The temperature will also
increase because temperature is a measure
of average kinetic energy.
(2bi)
Draw your diagram
(2bii)
C2H5OH + 3O2 ---->2CO2 + 3H2O
1mole of ethanol = 3moles of O2
2.5moles of ethanol will require 3 × 2.5/1 =
7.5moles of O2.
but 1 mole of gas = 22.4dm3
7.5moles = 7.5 × 22.4 = 168dm3 of O2.
2ci)
Esterification can be defined as the
reaction between ethanol and ethanoic acid
to form a reversible reaction of ethyl esters
CH3COOH + C2H5OH →← CH2COOC2H5 +
H2O
2Cii)
- it is used as anti-freeze in automobile
radiation
- it is used as fuel
(2ciii)
Sodium Ethanoate
(2di)
Tin
(2dii )
This is because the galvanized plate is
corrosion-resistant. It has a protective
coating which prevents further oxidation of
the metal.
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NO 4
4aii)
Na2SO3(aq) + 2HCl(aq)----->2Nacl(aq)+H2O
(s)+SO2(q)
4aiii)
dry the gas evolved by passing it through
H2SO4 and collect it by downward delivery
4aiv)
because it is denser than air
4bi)
Dalton's law of partial pressure states that
in a mixture of gases, which do not react
chemically together, a gas will exert a
partial pressure, which is the pressure, it
will exert if it is kept alone in the vessel.
4bii)
T1=12degree = 285k
P1=690mm Hg
V1=30cm^3
T2=273k
P2=760mmhg
V2=?
Using the general gas law
V1P1/T1 = V2P2/T2
V2=30*690*273/285*760
V2=261cm^3
V2=26cm^3
4ci)
Cl2(q)+H2O(i)------>HCL(aq)+HOCL(aq)
4cii)
litmus turn red because of the presence of
the acid HCL
4di)
chlorine bromine iodine/increasing boiling
point
4dii)
because water has two(2)ion pairs of
electrons as compared to ammonia which
has one
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