1997 - WAEC Chemistry Past Questions and Answers - page 3
21
How much heat will be liberated if 8g of hydrogen burns in excess oxygen according to the following equation? 2H2 + O2→ 2H2O,∆H = -571.7KJ (H = 1)
A
1.42.9KJ
B
571.7KJ
C
1143.4KJ
D
285.9KJ
correct option: c
Users' Answers & Comments22
The position of equilibrium in a reversible reaction is affected by
A
particle size of the reactants
B
change in concentration of the reactants
C
change in size of the reaction vessel
D
vigorous stirring of the reaction mixture
correct option: b
Users' Answers & Comments23
Separation of mixture of solids by physical methods can be based on differences in the following except
A
melting point
B
solubility
C
particle size
D
molar mass
correct option: d
Users' Answers & Comments24
Ethene undergoes mainly addition reactions because it is
A
a gas
B
a hydrocarbon
C
unsaturated
D
easily polymerized
correct option: c
Users' Answers & Comments25
The reaction between alkanoic acids and alkanols in the presence of a mineral acid is known as
A
saponification
B
hydrolysis
C
polymerization
D
esterification
correct option: d
Users' Answers & Comments26
Which of the following is the relative molecular mass of a compound which has empirical formula CH\(_2\)O? (H = 1; C = 12; O = 16)
A
42
B
45
C
126
D
180
correct option: d
Empirical formula = CH\(_2\)O
= 12 + (2 x 1) + 16
= 30
Molecular formula = (CH\(_2\)O)\(_n\), where n is a whole number.
= 30n
\(\therefore\) From the options, only 180 is a multiple of 30. Hence, that is the only likely molecular mass with respect to CH\(_2\)O.
27
The by-product of the fermentation of sugar to ethanol is
A
propane -1,2,3-triol
B
ethyl ethanoate
C
ethanedioc acid
D
propanol
correct option: e
Users' Answers & Comments28
Alkanes react with the halogens mainly by
A
oxidation
B
polymerization
C
addition
D
reduction
correct option: e
Users' Answers & Comments29
Which of the following is used widely in the manufacture of flavours and perfumes?
A
Alkanoates
B
Alkanones
C
Alkanes
D
Complex sugars
correct option: a
Users' Answers & Comments30
The use of diamond in abrasives is due ti its
A
high melting point
B
durability
C
lustre
D
hardness
correct option: d
Users' Answers & Comments