

NTSE SAT Chemistry - Atoms and Molecules
Exam Duration: 45 Mins Total Questions : 30
The number of Na atoms present in 23 g Na metal is
- (a)
23
- (b)
22 x 6.022 x 1023
- (c)
6.022 x 1023
- (d)
0.5 x 6.022 x 1023
How many moles of carbon dioxide are there in 44g CO2
- (a)
44
- (b)
22
- (c)
1
- (d)
4.4
80 g of NaOH is dissolved in 1 litre of water. The molarity of NaOH solution is
- (a)
0.1 M
- (b)
0.2 M
- (c)
1 M
- (d)
2 M
An atom of an element is 40 times heavier than 1/12th of the mass of 12C isotope. The atomic mass of the element is
- (a)
10 U
- (b)
12 U
- (c)
40 U
- (d)
20 U
The symbols for ferric ion and ammonium ion are respectively
- (a)
Fe2+, NH3
- (b)
Fe2+, NH4+
- (c)
Fe3+, NH4+
- (d)
Fe3+, NH2-
The symbol of manganese element is
- (a)
Mg
- (b)
Mo
- (c)
Mn
- (d)
Ma
In which of the following pairs the magnitude positive charge of the cation is equal to the negative charge of the anion
- (a)
Cupric ion and hydroxide ion
- (b)
Ferrous ion and hydroxide ion
- (c)
Cuprous ion and chloride ion
- (d)
Ferrous ion and chloride ion
Which of the following is a trivalent ion?
- (a)
Sulphide
- (b)
Carbide
- (c)
Oxide
- (d)
Nitride
Almost the entire mass of an atom is concentrated in the ____________
- (a)
proton
- (b)
electrons
- (c)
nucleus
- (d)
neutrons
The absolute charge of an electron is ________________
- (a)
1.6 x 10-19C
- (b)
+ 1.6 X 10-19C
- (c)
1.6 x 10-19C
- (d)
16 x 10-19C
Chadwick got the Nobel Prize for the discovery of _____________
- (a)
protons
- (b)
neutrons
- (c)
electrons
- (d)
mesons
Mass number is equal to the ____________
- (a)
number of protons + number of electrons
- (b)
number of protons + number of neutrons
- (c)
number of neutrons + number of electron
- (d)
number of electrons
The fixed circular paths around the nucleus are called ___________
- (a)
orbits
- (b)
orbitals
- (c)
nucleous
- (d)
mesons
An example of a tri-atomic molecule is _____________
- (a)
Ozone
- (b)
Nitrogen
- (c)
Carbon monoxide
- (d)
Hydrogen
The quantity of matter present in an object is called its ___________
- (a)
Mass
- (b)
Volume
- (c)
Density
- (d)
Vapour pressure
Indivisibility of an atom was proposed by ___________
- (a)
Dalton
- (b)
Rutherford
- (c)
Thomson
- (d)
Bohr
The value of Avogadro constant is _____________
- (a)
6.022X1024
- (b)
60.22 X 1022
- (c)
60.222 X 1023
- (d)
6.022 X 1023
The atomic mass of sodium is 23. The number of moles in 46 g of sodium is ____________ .
- (a)
2
- (b)
1
- (c)
4
- (d)
0
The molecular formula of potassium nitrate is ____________
- (a)
KNO
- (b)
KNO3
- (c)
KNO2
- (d)
KON
The molecular mass of ammonia is _____________
- (a)
17 grams
- (b)
31 grams
- (c)
20 grams
- (d)
25 grams
Atomic mass of calcium is 40. The mass of2.5 gram atoms of calcium is _____________.
- (a)
40 g
- (b)
2.5 g
- (c)
100 g
- (d)
80 g
The number of atoms in a molecule of the elementary substance is called ___________
- (a)
Atomic number
- (b)
Avogadro number
- (c)
Atomic number
- (d)
Atomicity
The number of moles in 5 grams of calcium is ___________.
- (a)
0.125 mole
- (b)
5 mole
- (c)
1.25 mole
- (d)
12.5 mole
When 5 g of Calcium is burnt in 2 g of Oxygen then 7 g of Calcium oxide is produced. What mass of calcium oxide will be produced when 5 g of calcium reacts with 20 g of oxygen?
- (a)
7g
- (b)
2g
- (c)
25g
- (d)
4g
Which postulate of Dalton's atomic theory explains the law of constant proportion?
- (a)
Atoms cannot be divided
- (b)
All the matter is made up of very small particles called atoms.
- (c)
Elements consist of atoms combined in a fixed ratio.
- (d)
Atoms can neither be created nor be destroyed
Which of the following set of ions is present in potassium sulphate (K2SO4)?
- (a)
K4, SO4-2
- (b)
K+4, SO2
- (c)
K+4, SO4-
- (d)
K+, SO4-
Two elements A (atm wt 75) and B (atm wt. 165) combine to yield a compound.the percentage by weight of A in the compound was found to be 75.08.The formula of the compound is
- (a)
AB
- (b)
AB2
- (c)
A2B
- (d)
A2B3
number of carbon atoms in 1 g of CaCO3 is
- (a)
6.023 x 1023
- (b)
6.023 x 1021
- (c)
3.0125 x 1022
- (d)
1.204 x 1023
The volume of one mole of a gas at normal temperature and pressure
- (a)
11.2 litres
- (b)
22.4litres
- (c)
100litres
- (d)
None of these
The number of gram atoms in 8 g of e are
- (a)
2
- (b)
1.204 x 1024
- (c)
3.1 x 1023
- (d)
None of these