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OTI365 - NTSE - X Standard
NTSE SAT Chemistry - Atoms and Molecules Model Questions

NTSE SAT Chemistry - Atoms and Molecules

Exam Duration: 45 Mins Total Questions : 30

1 )

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

2 )

How many moles of carbon dioxide are there in 44g CO₂

(a)
44
(b)
22
(c)
1
(d)
4.4

3 )

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

4 )

An atom of an element is 40 times heavier than 1/12^th 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

5 )

The symbols for ferric ion and ammonium ion are respectively

(a)
Fe²⁺, NH₃
(b)
Fe²⁺, NH₄⁺
(c)
Fe³⁺, NH₄⁺
(d)
Fe³⁺, NH₂^-

6 )

The symbol of manganese element is

(a)
Mg
(b)
Mo
(c)
Mn
(d)
Ma

7 )

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

8 )

Which of the following is a trivalent ion?

(a)
Sulphide
(b)
Carbide
(c)
Oxide
(d)
Nitride

9 )

Almost the entire mass of an atom is concentrated in the ____________

(a)
proton
(b)
electrons
(c)
nucleus
(d)
neutrons

10 )

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

11 )

Chadwick got the Nobel Prize for the discovery of _____________

(a)
protons
(b)
neutrons
(c)
electrons
(d)
mesons

12 )

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

13 )

The fixed circular paths around the nucleus are called ___________

(a)
orbits
(b)
orbitals
(c)
nucleous
(d)
mesons

14 )

An example of a tri-atomic molecule is _____________

(a)
Ozone
(b)
Nitrogen
(c)
Carbon monoxide
(d)
Hydrogen

15 )

The quantity of matter present in an object is called its ___________

(a)
Mass
(b)
Volume
(c)
Density
(d)
Vapour pressure

16 )

Indivisibility of an atom was proposed by ___________

(a)
Dalton
(b)
Rutherford
(c)
Thomson
(d)
Bohr

17 )

The value of Avogadro constant is _____________

(a)
6.022X10²⁴
(b)
60.22 X 10²²
(c)
60.222 X 10²³
(d)
6.022 X 10²³

18 )

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

19 )

The molecular formula of potassium nitrate is ____________

(a)
KNO
(b)
KNO₃
(c)
KNO₂
(d)
KON

20 )

The molecular mass of ammonia is _____________

(a)
17 grams
(b)
31 grams
(c)
20 grams
(d)
25 grams

21 )

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

22 )

The number of atoms in a molecule of the elementary substance is called ___________

(a)
Atomic number
(b)
Avogadro number
(c)
Atomic number
(d)
Atomicity

23 )

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

24 )

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

25 )

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

26 )

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^-

27 )

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