Atoms And Molecules Test

Result

Atoms And Molecules Test - 1

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

H₂O, obtained from different sources, always contains hydrogen and oxygen atoms in the respective ratio of 2 : 1. This is in accordance with which of the following?

A
Law of Multiple Proportions

B
Law of Reciprocal Proportions

C
Law of Definite Proportions

D
Law of Conservation of Energy

Solution

Law of definite proportions states that elements combine in a fixed proportion by mass to form compounds. Hence, the mass as well as the number of atoms of each element in the molecule of a compound is fixed.
Question 2
1 / -0

Which among the following illustrate the law of reciprocal proportions?

A
H₂O and H₂O₂

B
SO₂ and SO₃

C
CH₄, CO₂ and H₂O

D
None of these

Solution

In CH₄ and CO₂, the masses of hydrogen and oxygen that react with 12 g of carbon are in respective ratios of 4 : 32 or 1 : 8.

In H₂O, ratio of mass of hydrogen to mass of oxygen = 1 : 8

Hence, the law of reciprocal proportions is being illustrated by CH₄, CO₂ and H₂O.

H₂O and H₂O₂ illustrate the law of multiple proportions.

SO₂and SO₃ also illustrate the law of multiple proportions.

Question 3

1 / -0

Nitrogen and oxygen form three oxides.

In oxide I, 1.00 g of nitrogen combines with 0.57 g of oxygen.
In oxide II, 2.00 g of nitrogen combines with 2.24 g of oxygen.
In oxide III, 3.00 g of nitrogen combines with 5.11 g of oxygen.

These results are in accordance with which of the following?

Law of Definite Proportions

Law of conservation of mass

Law of Reciprocal Proportions

Law of Multiple Proportions

Solution

Compound	Mass of nitrogen	Mass of oxygen	Mass of oxygen that reacts with 1 g of nitrogen	Ratio of the mass of oxygen to the mass of oxygen that reacts with 1 g of nitrogen
Oxide I	1 g	0.57 g	0.57 g	1
Oxide II	2 g	2.24 g	1.12 g	1.96 ≈ 2
Oxide III	3 g	5. 11 g	1.70 g	2.988 ≈ 3

Hence, the data illustrates the law of multiple proportions.

Question 4
1 / -0

Nitrogen and hydrogen react to form ammonia, as shown below:

N₂ (g) + 3H₂ (g) → 2NH₃ (g)

The volume of hydrogen required to react completely with 10 L of N2 and the volume of NH3 produced, respectively, are

A
10 L and 10 L

B
30 L and 15 L

C
30 L and 20 L

D
20 L and 10 L

Solution

The balanced equation shows:

n(N₂) : n(H₂) : n(NH₃) = 1 : 3 : 2

According to the Avogadro's law:

Volume ratio = Molar ratio

V(N₂) : V(H₂) : V(NH₃) = 1 : 3 : 2

Therefore, the volume of H₂ required is 30 L and the volume of NH₃ produced is 20 L.
Question 5
1 / -0

According to Dalton's theory, which of the following particles is indivisible and cannot be created or destroyed in a chemical reaction?

A
Proton

B
Electron

C
Atom

D
Neutron

Solution

According to Dalton's theory, an atom is the constituent particle of all matter and cannot be created or destroyed during any physical or chemical change.

The sub-atomic particles - electrons, protons and neutrons - were not known at the time when Dalton gave his theory.
Question 6
1 / -0

Which of the following statements contradict Dalton's atomic theory?

(A) A chemical change involves rearrangement of atoms.
(B) Atoms form ions by gain or loss of electrons.
(C) The number of atoms may change when a substance changes from solid to gaseous state.
(D) The total number of atoms during a chemical change remains unaltered.

A
A and B only

B
B and C only

C
C and D only

D
A and C only

Solution

Statement B contradicts Dalton's atomic theory because the theory proposes that atoms are indivisible and it does not talk of sub-atomic particles.

Statement C contradicts Dalton's atomic theory, which states that atom is indestructible.
Question 7
1 / -0

Two elements, X and Y, have 5 and 7 valence electrons, respectively. What will be the most probable formula of the compound formed by them?

A
X₇Y₅

B
X₅Y₇

C
X₃Y

D
XY₃

Solution

Both X and Y are non-metals and will associate through covalent bonds.
X has 5 valence electrons and its valency is 3.
Y has 7 valence electrons and its valency is 1.

Therefore, the formula of the compound will be: XY₃.
Question 8
1 / -0

The atomic numbers of four elements - A, B, C and D - are 6, 8, 10 and 12, respectively. The two elements which can react to form an ionic bond are

A
A and D

B
B and C

C
A and C

D
B and D

Solution

A (Z = 6) is carbon and its electronic configuration is: 2, 4.
B (Z = 8) is oxygen and its electronic configuration is: 2, 6.
C (Z = 10) is neon and its electronic configuration is: 2, 8.
D (Z = 12) is magnesium and its electronic configuration is: 2, 8, 2.

Magnesium is a metal and oxygen is a non-metal and they react to form an ionic oxide.
Neon is a noble gas and does not react, whereas carbon forms covalent compounds.
Question 9
1 / -0

The gaseous hydrocarbon acetylene, C₂H₂,used in welder's torches, releases 1300 KJ when 1 mole of C₂H₂undergoes combustion. Which of the following statements is not true?

A
Combustion of acetylene is an exothermic reaction.

B
The balanced chemical reaction of combustion of acetylene is: C₂H₂ + 5O₂→ 2CO₂ + H₂O.

C
Two moles of water are produced when two moles of acetylene react.

D
44 g of CO₂isproduced when 13 g of acetylene reacts.

Solution

Balanced chemical reaction: 2C₂H₂ + 5O₂ → 4CO₂ + 2H₂O

Hence, option (2) is incorrect.

Since heat is liberated, the reaction is exothermic. Hence, option (1) is correct.

It is evident from the balanced reaction that 2 moles of water are produced when 2 moles of acetylene react.

Hence, option (3) is correct.

It is also evident that the number of moles of CO₂produced is twice the number of moles of C₂H₂ reacted.

Hence, combustion of 13 g (0.5 mole) of C₂H₂ would produce 44 g (1 mole) of CO₂. Hence, option (4) is correct.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Atoms And Molecules Test - 1

Result

Atoms And Molecules Test - 1

Score

-

Rank

-

SHARING IS CARING

Question 1

Law of Multiple Proportions

Law of Reciprocal Proportions

Law of Definite Proportions

Law of Conservation of Energy

Solution

Question 2

H2O and H2O2

SO2 and SO3

CH4, CO2 and H2O

None of these

Solution

Question 3

Law of Definite Proportions

Law of conservation of mass

Law of Reciprocal Proportions

Law of Multiple Proportions

Solution

Question 4

10 L and 10 L

30 L and 15 L

30 L and 20 L

20 L and 10 L

Solution

Question 5

Proton

Electron

Atom

Neutron

Solution

Question 6

A and B only

B and C only

C and D only

A and C only

Solution

Question 7

X7Y5

X5Y7

X3Y

XY3

Solution

Question 8

A and D

B and C

A and C

B and D

Solution

Question 9

Combustion of acetylene is an exothermic reaction.

The balanced chemical reaction of combustion of acetylene is: C2H2 + 5O2 → 2CO2 + H2O.

Two moles of water are produced when two moles of acetylene react.

44 g of CO2 is produced when 13 g of acetylene reacts.

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.

H₂O and H₂O₂

SO₂ and SO₃

CH₄, CO₂ and H₂O

X₇Y₅

X₅Y₇

X₃Y

XY₃

The balanced chemical reaction of combustion of acetylene is: C₂H₂ + 5O₂→ 2CO₂ + H₂O.

44 g of CO₂isproduced when 13 g of acetylene reacts.