2014 - JAMB Chemistry Past Questions and Answers - page 1
1
A mixture is different from a compound because
A
the properties of a compound are those of its individual constituents while those of a mixture differ from its constituents
B
a mixture is always homogeneous while a compound is not
C
the constituent of a compound are chemically bound together while those of a mixture are not
D
a mixture can be represented by a chemical formula while a compound cannot
correct option: c
Users' Answers & Comments2
What is the percentage of sulphur in sulphur (IV) oxide?
A
66%
B
25%
C
40%
D
50%
3
A gas X diffuses twice as fast as gas Y. if the relative molecular mass of X is 32, calculate the relative molecular mass of Y.
A
128
B
8
C
16
D
64
correct option: a
\(\frac{RY}{RX}\) = \(\frac{\sqrt{My}}{\sqrt{My}}\) 1/2 = \(\frac{\sqrt{32}}{\sqrt{y}}\) \(\frac{32}{y}\) = 1/4
Y = \(\frac{32x4}{1}\) = 128
Users' Answers & CommentsY = \(\frac{32x4}{1}\) = 128
4
200 cm3 of a gas at 25oC exerts a pressure of 700 mmHg. Calculate its pressure if its volume increase 350 cm3 at 75oC.
A
342.53 mmHg
B
1430.54 mmHg
C
467.11 mmHg
D
400.00 mmHg
correct option: c
\(\frac{p 1V 1}T 1\) = \(\frac{P 2V 2}{T 2}\) \(\frac{700x200}{298}\) = \(\frac{P2X 350}{348}\) P2 = \(\frac{700x200x348}{298x350}\) = 467.11mmHg
Users' Answers & Comments5
An element X has electron configuration 1s2 2s2 2p6 3s2 3p5. Which of the following statements is correct about the element?
A
lt has a completely filled p-orbital
B
lt has 5 electrons in its outermost shell.
C
lt belongs to group ll on the periodic table
D
lt is a halogen
correct option: d
Users' Answers & Comments6
Beryllium and aluminium have similar properties because they
A
are both metals
B
belong to the same group
C
belong to the same period
D
are positioned diagonally to each other
correct option: d
At the beginning of periods 2 and 3 of the Periodic Table, there are several cases where an element at the top of one group has some similarities with an element in the next group.
For example, boron is a non-metal with some properties rather like silicon. Unlike the rest of Group 2, beryllium has some properties resembling aluminium. And lithium has some properties which differ from the other elements in Group 1, and in some ways resembles magnesium.
There is said to be a diagonal relationship between these elements.
There are several reasons for this, but each depends on the way atomic properties like electronegativity vary around the Periodic Table.
Users' Answers & CommentsFor example, boron is a non-metal with some properties rather like silicon. Unlike the rest of Group 2, beryllium has some properties resembling aluminium. And lithium has some properties which differ from the other elements in Group 1, and in some ways resembles magnesium.
There is said to be a diagonal relationship between these elements.
There are several reasons for this, but each depends on the way atomic properties like electronegativity vary around the Periodic Table.
7
If the difference in electronegativity of elements P and Q is 3.0. The bond that will be formed between them is
A
metallic
B
covalent
C
co-ordinate
D
ionic
correct option: d
Users' Answers & Comments8
How many protons, neutrons and electrons respectively are present in the element 60/27 Co?
A
27, 33 and 33
B
33, 27 and 27
C
27, 33, and 27
D
60, 33 and 60
correct option: c
Users' Answers & Comments9
The radio active radiation used in studying the arrangement of particles in giant organic molecules is
A
\(\gamma\)- rays
B
\(\alpha\)- particles
C
X-rays
D
\(\beta\) - particles
correct option: c
Users' Answers & Comments10
A silicon -containing ore has 92% 28Si, 5% 29Si and 3% 30Si. Calculate the relative atomic mass of the silicon.
A
14.00
B
29.00
C
28.11
D
28.00
correct option: c
(\(\frac{92}{100}\) x 28) + (\(\frac{5}{100}\) x 29) + (\(\frac{3}{100}\) x 230) = 28.11
Users' Answers & Comments