EXAM QUESTIONS WITH VERIFIED
ANSWERS(NEWEST RELEASE).
What is a composite material? - CorreCt Answers -A material made up of
two materials with different properties
What is a composite material made up of? - CorreCt Answers -A material
made from two components, a matrix or binder surrounding and binding
fibres or fragments of the other material, which is called the reinforcement
Give four examples of composite materials - CorreCt Answers -Reinforced
steel (reinforcement:steel, matrix:concrete), Fibreglass (glass fibres,
polymer resin), carbon fibre (carbon fibres, polymer resin), chipboard (
wood chips, resin glue)
What is the Haber process used to manufacture? - CorreCt Answers -
Ammonia
What is ammonia used to make? - CorreCt Answers -Nitrogen-based
fertilisers
What are the raw materials for the Haber process - CorreCt Answers -
Nitrogen from the air and hydrogen from natural gas
What is the symbol equation for the Haber process? - CorreCt Answers -N2
(g) + 3H2 (g) D 2NH3 (g)
,Describe the Haber process (reversible reaction) - CorreCt Answers -
Purified gases are passed over a catalyst at 450°C and 200 atmospheres.
Some of the hydrogen and nitrogen react to form ammonia which on
cooling liquifies and is removed. The remaining hydrogen and nitrogen are
recycled.
Which conditions would produce the highest yield of ammonia? - CorreCt
Answers -Low temperature, high pressure
Why does a low temperature produce a higher yield of ammonia? - CorreCt
Answers -The forward reaction is exothermic so a lower temperature moves
the equilibrium to the right to increase the temperature making more
products
Why does a high pressure increase the yield of ammonia? - CorreCt
Answers -There are fewer molecules on the right hand side of the reaction
so the equilibrium will shift to the right to reduce the pressure
Why is a temperature of 450°C used in the Haber process? - CorreCt
Answers -It is a compromised temperature to produce a reasonable yield of
ammonia at a suitable rate
Why is a pressure of 200 atmosphere used in the Haber process? - CorreCt
Answers -To increase the yield of ammonia without incurring the very high
energy and equipment costs for achieving very high pressures
,What effect does using a catalyst have on the yield of ammonia in the Haber
process? - CorreCt Answers -None. It just reduces the time for the system to
reach equilibrium.
What types of compounds are used in artificial fertilisers? - CorreCt
Answers -Compounds of nitrogen, phosphorus and potassium are used to
make NPK fertilisers
What are NPK fertilizers? - CorreCt Answers -Formulations of various salts
containing appropriate percentages of the elements (nitrogen, phosphorus
and potassium)
Name the salts that are used to provide nitrogen, phosphorus and
potassium in fertilisers - CorreCt Answers -Ammonium nitrate (NH4NO3),
ammonium sulfate ((NH4)2SO4), ammonium phosphate ((NH3)3
PO3),potassium nitrate (KNO3)
What is ammonia used to manufacture? - CorreCt Answers -Ammonium
salts and nitric acid
Where are potassium salts obtained from for fertilisers? - CorreCt Answers
-By mining
Where is phosphate rock obtained from for fertilisers? - CorreCt Answers -
By mining
What does phosphate rock have to be treated with before it can be used as a
fertiliser? - CorreCt Answers -Acid
, What is produced when phosphate rock is treated with nitric acid? -
CorreCt Answers -Calcium nitrate and phosphoric acid
What is produced when phosphate rock is treated with sulfuric acid? -
CorreCt Answers -Single superphosphate (a mixture of calcium sulfate and
calcium phosphate)
What is produced when phosphate rock is treated with phosphoric acid? -
CorreCt Answers -Triple superphosphate (calcium phosphate)What theory
can we use to explain how various factors affect the rate of a reaction? -
CorreCt Answers -Collision theory
What is collision theory? - CorreCt Answers -Chemical reactions can occur
only when reacting particles collide with each other and with sufficient
energy
What is the activation energy of a reaction? - CorreCt Answers -The
minimum amount of energy that particles must have to react
How do you increase the surface area of a solid reactant? - CorreCt
Answers -Grind it into a powder that has smaller particle size
What effect does increasing the temperature of a reaction by 10°C have on
the rate of a reaction? - CorreCt Answers -It doubles it
What is a catalyst? - CorreCt Answers -A chemical that changes the rate of a
chemical reaction but is not used up in the reaction